Characteristics of heat transfer and flow of Newtonian and non-Newtonian fluids through porous walls and in porous media are studied due to their wide range of applications including geothermal reservoirs,heat exchang...Characteristics of heat transfer and flow of Newtonian and non-Newtonian fluids through porous walls and in porous media are studied due to their wide range of applications including geothermal reservoirs,heat exchangers,marine propulsion,and aerodynamics.The current study investigates the characteristics of heat transport in a reactive third-grade fluid,moving through permeable parallel plates,with uniform suction/injection velocity.The two permeable,parallel plates are maintained at the same,constant temperature.After being transformed into its dimensionless equivalent,governing equations are solved by employing the Least Squares Method(LSM).The LSM results are further validated with numerical solutions for temperature and velocity.The impact of cross-flow Reynolds number,Peclet number,heat generation parameter,non-Newtonian parameter,and Brinkman number on entropy generation,velocity,temperature,and Bejan number are investigated.Theresults indicate that temperature distribution is significantly influenced by the third-grade fluid parameter.The maximum temperature drops from almost 0.12 to 0.10 as the third-grade fluid parameter increases from0.05 to 0.4.When the cross-flow Reynolds number is raised from 0.05 to 3,the maximum temperature drops from 0.12 to around 0.09.Temperature is strongly influenced by the heat generation parameter.A greater understanding of the thermal characteristics necessary for the design of a variety of systems,such as heat exchangers,marine propulsion,aerodynamic systems,etc.,may be gained from the findings of the current study.展开更多
This paper introduces the effect of heat absorption(generation)and suction(injection)on magnetohydrodynamic(MHD)boundary-layer flow of Casson nanofluid(CNF)via a non-linear stretching surface with the viscous dissipat...This paper introduces the effect of heat absorption(generation)and suction(injection)on magnetohydrodynamic(MHD)boundary-layer flow of Casson nanofluid(CNF)via a non-linear stretching surface with the viscous dissipation in two dimensions.By utilizing the similarity transformations,the leading PDEs are transformed into a set of ODEs with adequate boundary conditions and then resolved numerically by(4–5)^(th)-order Runge-Kutta Fehlberg procedure based on the shooting technique.Numerical computations are carried out by Maple 15 software.With the support of graphs,the impact of dimensionless control parameters on the nanoparticle concentration profiles,the temperature,and the flow velocity are studied.Other parameters of interest,such as the skin friction coefficient,heat,and mass transport at the diverse situation and dependency of various parameters are inspected through tables and graphs.Additionally,it is verified that the numerical computations with the reported earlier studies are in an excellent approval.It is found that the heat and mass transmit rates are enhanced with the increasing values of the power-index and the suction(blowing)parameter,whilst are reduced with the boosting Casson and the heat absorption(generation)parameters.Also,the drag force coefficient is an increasing function of the powerindex and a reduction function of Casson parameter.展开更多
Several new techniques in the field of heat transfer in fluids have opened new avenues for studying the heat transfer effects in nanofluids and thermodynamic flow parameters, leading to novel applications. There have ...Several new techniques in the field of heat transfer in fluids have opened new avenues for studying the heat transfer effects in nanofluids and thermodynamic flow parameters, leading to novel applications. There have been studies on nanofluids, including metal, ceramic and magnetic nanoparticles mixed with base fluids such as Water, Kerosene, and Ethylene glycol. However, research on fluids employing semiconductor nanoparticles as supplements to base fluids to generate nanofluids and hybrid nanofluids is limited. For the investigation, Gallium nitrite, a binary semiconductor with excellent heat convection, is together with Cu metal nanoparticles and Al<sub>2</sub>O<sub>3</sub> ceramic nanoparticles separately in the base fluid Ethylene glycol (EG) to form hybrid nanofluids. The effects of convective boundary conditions, thermal radiation, heat source/sink, suction/injection, and activation energy on three-dimensional Williamson MHD hybrid nanofluid flow of Cu + GaN + EG, Al<sub>2</sub>O<sub>3</sub> + GaN + EG, and Cu + Al<sub>2</sub>O<sub>3</sub> + EG are investigated on a stretched sheet with porosity. A similarity transformation is performed on the governing equations to transform them into dimensionless ordinary differential equations ODEs. Numerical analysis is carried out in MATLAB utilizing bvp5c and the shooting technique. The variations of velocity, temperature, and concentration profiles as a function of different physical effects are presented graphically with dimensionless parameters and explained the variations scientifically. As varied with different parameters, the values of the Skin-friction coefficient, Nusselt number, and Sherwood number are mentioned in the table.展开更多
The aim of this work is to study the effect of non-uniform single and double slot suction/injection into a steady mixed convection boundary layer flow over a vertical cone, while the axis of the cone is inline with th...The aim of this work is to study the effect of non-uniform single and double slot suction/injection into a steady mixed convection boundary layer flow over a vertical cone, while the axis of the cone is inline with the flow. The governing boundary layer equations are transformed into a non-dimensional form by a group of non-similar trans- formations. The resulting coupled non-linear partial differential equations are solved nu- merically by employing the quasi-linearization technique and an implicit finite-difference scheme. Numerical computations are performed for different values of the dimensionless parameters to display the velocity and temperature profiles graphically. Also, numerical results are presented for the skin friction and heat transfer coefficients. Results indicate that the skin friction and heat transfer coefficients increase with non-uniform slot suction, but the effect of non-uniform slot injection is just opposite.展开更多
The work presented herein investigates the velocity, heat transfer, Nusselt number and skin friction profiles involved in boundary layer flow past a moving vertical porous plate. Similarity transformations are employe...The work presented herein investigates the velocity, heat transfer, Nusselt number and skin friction profiles involved in boundary layer flow past a moving vertical porous plate. Similarity transformations are employed to convert the governing nonlinear unsteady momentum and energy equations from their partial differential equation forms to boundary value ordinary differential equations. The resulting equations are then solved numerically by the Runge-Kutta fourth order method with the help of a shooting technique. Several features of the flow and heat transfer characteristics for different values of problem parameters are analyzed and discussed. These include the effects of the radiation parameter (R), suction and injection parameter (c), Grashof (Gr) and Prandtl (Pr) numbers on the flow and heat profiles. Numerical results show the impact of blowing and sucking as well as radation on boundary layer flows of this type. Both the skin frictions as well as the heat transfer rate are also significantly related to the radiation parameter. For all these cases;the numerical results are found to be in agreement with the physics of the problem.展开更多
In this paper,an investigation is made to study the effects of radiation and heat source/sink on the unsteady boundary layerflow and heat transfer past a shrinking sheet with suction/injection.Theflow is permeated by an...In this paper,an investigation is made to study the effects of radiation and heat source/sink on the unsteady boundary layerflow and heat transfer past a shrinking sheet with suction/injection.Theflow is permeated by an externally applied magneticfield normal to the plane offlow.The self-similar equations correspond-ing to the velocity and temperaturefields are obtained,and then solved numerically byfinite difference method using quasilinearization technique.The study reveals that the momentum boundary layer thickness increases with increasing unsteadiness and decreases with magneticfield.The thermal boundary layer thickness decreases with Prandtl number,radiation parameter and heat sink parameter,but it increases with heat source parameter.Moreover,increasing unsteadiness,magneticfield strength,radiation and heat sink strength boost the heat transfer.展开更多
The present study reveals the effect of nonlinear thermal radiation and magnetic field on a boundary layer flow of a viscous fluid over a nonlinear stretching sheet with suction or an injection. Using suitable similar...The present study reveals the effect of nonlinear thermal radiation and magnetic field on a boundary layer flow of a viscous fluid over a nonlinear stretching sheet with suction or an injection. Using suitable similarity transformations, governing partial differential equations were reduced to higher order ordinary differential equations and further these are solved numerically using of Keller-Box method. Effect of flow controlling parameter on velocity, temperature and nanoparticle fluid concentration, local skin friction coefficient, local Nusselt number and local Sherwood numbers are discussed. It is found that the dimensionless velocity decreases and temperature, concentration are increased with the increasing of magnetic parameter. The temperature profile is an increasing function of thermal radiation when it is increasing.展开更多
The magnetohydrodynamic(MHD)boundary layer slipflow and solute transfer over a porous plate in the presence of a chemical reaction are investigated.The governing equations were transformed into self-similar ordinary di...The magnetohydrodynamic(MHD)boundary layer slipflow and solute transfer over a porous plate in the presence of a chemical reaction are investigated.The governing equations were transformed into self-similar ordinary differential equations by adopting the similarity transformation technique.Then the numerical solutions are obtained by a shooting technique using the fourth order Runge-Kutta method.The study reveals that due to the increase in the boundary slip,the concentration decreases and the velocity increases.On the other hand,with an increase in the magneticfield and mass suction,both boundary layer thicknesses decreased.As the Schmidt number and the reaction rate parameter increases,the concentration decreases and the mass transfer increases.展开更多
Combined heat and mass transfer on free, forced, and mixed convection flow along a porous wedge with magnetic effect in the presence of chemical reaction is investigated. The flow field characteristics are analyzed by...Combined heat and mass transfer on free, forced, and mixed convection flow along a porous wedge with magnetic effect in the presence of chemical reaction is investigated. The flow field characteristics are analyzed by the Runge-Kutta-Gill scheme with the shooting method as well as the local non-similarity method up to the third level of truncation, which are used to reduce the governing partial differential equations into nine ordinary differential equations. The governing boundary layer equations are converted to a dimensionless form by Falkner-Skan transformations. Because of the effect of suction/injection on the wall of the wedge with buoyancy force and variable wall temperature, the flow field is locally non-similar. Numerical calculations up to the third order level of truncation are carried out as a special case for different values of dimensionless parameters. Effects of the magnetic field strength in the presence of chemical reaction with variable wall temperature and concentration on the dimensionless velocity, temperature and concentration profiles are shown graphically.展开更多
An analysis is performed to study the heat transfer characteristics of steady two-dimensional boundary layer flow past a moving permeable flat plate in a nanofluid. The effects of uniform suction and injection on the ...An analysis is performed to study the heat transfer characteristics of steady two-dimensional boundary layer flow past a moving permeable flat plate in a nanofluid. The effects of uniform suction and injection on the flow field and heat transfer characteristics are numerically studied by using an implicit finite difference method. It is found that dual solutions exist when the plate and the free stream move in the opposite directions. The results indicate that suction delays the boundary layer separation, while injection accelerates it.展开更多
Hydrogen displays the potential to partially replace pulverized coal injection(PCI)in the blast furnace,and it can reduce CO_(2)emissions.In this paper,a three-dimensional mathematical model of hydrogen and pulverized...Hydrogen displays the potential to partially replace pulverized coal injection(PCI)in the blast furnace,and it can reduce CO_(2)emissions.In this paper,a three-dimensional mathematical model of hydrogen and pulverized coal co-injection in blast furnace tuyere was established through numerical simulation,and the effect of hydrogen injection and oxygen enrichment interaction on pulverized coal combustion and raceway smelting was investigated.The simulation results indicate that when the coal injection rate decreased from 36 to 30t/h and the hydrogen injection increased from 0 to 3600 m^(3)/h,the CO_(2)emissions decreased from 1860 to 1551 kg/t,which represents a16.6%reduction,and the pulverized coal burnout decreased from 70.1%to 63.7%.The heat released from hydrogen combustion can not only promote the volatilization of pulverized coal but also affect the combustion reaction between volatilization and oxygen,which resulted in a decrease in the temperature at the end of the raceway.Co-injection of hydrogen with PCI increased the wall temperature near the upper half part of the raceway and at the outlet of the tuyere,which required a high cooling efficiency to extend the service life of the blast furnace.The increase in oxygen level compensated for the decreased average temperature in the raceway due to hydrogen injection.The increase in the oxygen content by 3%while maintaining constant hydrogen and PCI injection rates increased the burnout and average raceway temperature by 4.2%and 43 K,respectively.The mole fraction of CO and H_(2) production increased by 0.04 and 0.02,respectively.Burnout can be improved through optimization of the particle size distribution of pulverized coal.展开更多
BACKGROUND A total of 100 patients diagnosed with mixed hemorrhoids from October 2022 to September 2023 in our hospital were randomly divided into groups by dice rolling and compared with the efficacy of different tre...BACKGROUND A total of 100 patients diagnosed with mixed hemorrhoids from October 2022 to September 2023 in our hospital were randomly divided into groups by dice rolling and compared with the efficacy of different treatment options.AIM To analyze the clinical effect and prognosis of mixed hemorrhoids treated with polidocanol injection combined with automatic elastic thread ligation operation(RPH).METHODS A total of 100 patients with mixed hemorrhoids who visited our hospital from October 2022 to September 2023 were selected and randomly divided into the control group(n=50)and the treatment group(n=50)by rolling the dice.The procedure for prolapse and hemorrhoids(PPH)was adopted in the control group,while polidocanol foam injection+RPH was adopted in the treatment group.The therapeutic effects,operation time,wound healing time,hospital stay,pain situation(24 hours post-operative pain score,first defecation pain score),quality of life(QOL),incidence of complications(post-operative hemorrhage,edema,infection),incidence of anal stenosis 3 months post-operatively and recurrence rate 1 year post-operatively of the two groups were compared.RESULTS Compared with the control group,the total effective rate of treatment group was higher,and the difference was significant(P<0.05).The operation time/wound healing time/hospital stay in the treatment group were shorter than those in the control group(P<0.05).The pain scores at 24 hours after operation/first defecation pain score of the treatment group was significantly lower than those in the control group(P<0.05).After surgery,the QOL scores of the two groups decreased,with the treatment group having higher scores than that of the control group(P<0.05).Compared with the control group,the incidence of postoperative complications in the treatment group was lower,and the difference was significant(P<0.05);However,there was no significant difference in the incidence of postoperative bleeding between the two groups(P>0.05);There was no significant difference in the incidence of anal stenosis 3 months after operation and the recurrence rate 1 year after operation between the two groups(P>0.05).CONCLUSION For patients with mixed hemorrhoids,the therapeutic effect achieved by using polidocanol injection combined with RPH was better.The wounds of the patients healed faster,the postoperative pain was milder,QOL improved,and the incidence of complications was lower,and the short-term and long-term prognosis was good.展开更多
This study proposes and systematically evaluates an optimized integration of warm surface seawater injection with depressurization for the long-term exploitation of marine natural gas hydrates.By employing comprehensi...This study proposes and systematically evaluates an optimized integration of warm surface seawater injection with depressurization for the long-term exploitation of marine natural gas hydrates.By employing comprehensive multiphysics simulations guided by field data from hydrate production tests in the South China Sea,we pinpoint key operational parameters—such as injection rates,depths,and timings—that notably enhance production efficiency.The results indicate that a 3-phase hydrate reservoir transitions from a free-gas-dominated production stage to a hydrate-decomposition-dominated stage.Moderate warm seawater injection supplies additional heat during the hydrate decomposition phase,thereby enhancing stable production;however,excessively high injection rates can impede the depressurization process.Only injection at an appropriate depth simultaneously balances thermal supplementation and the pressure gradient,leading to higher overall productivity.A“depressurization-driven sensible-heat supply window”is introduced,highlighting that timely seawater injection following initial depressurization prolongs reservoir dissociation dynamics.In this study area,commencing seawater injection at 170 d of depressurization proved optimal.This optimized integration leverages clean and renewable thermal energy,providing essential insights into thermal supplementation strategies with significant implications for sustainable,economically feasible,and efficient commercial-scale hydrate production.展开更多
During high-speed rotation,the surface of aeronautic spiral bevel gears will generate significant pressure and viscous forces,which will cause a certain amount of windage power loss and reduce the efficiency of the tr...During high-speed rotation,the surface of aeronautic spiral bevel gears will generate significant pressure and viscous forces,which will cause a certain amount of windage power loss and reduce the efficiency of the transmission system.Based on the computational fluid dynamics,this paper analyzes the windage power loss of a single spiral bevel gear and a spiral bevel gear pair under oil injection lubrication.In addition,the shroud is used to suppress gear windage loss,and the clearance size and opening angle of the designed shroud are optimized.Finally,by comparing and analyzing the experimental results,the following conclusions were obtained:(1)For a single gear,the speed is the most important factor affecting windage loss,followed by the hand of spiral,and rotation direction;(2)For gear pairs,under oil injection lubrication,the input speed has the greatest impact on windage power loss,followed by the influence of oil injection port speed,temperature and oil injection port pressure;(3)Installing a shroud is an effective method to reduce windage power loss;(4)In the pure air phase,the smaller the clearance between the shroud and the gear surface,and the smaller the radial direction between the shroud and the shaft,the better the effect of reducing windage;(5)In the two-phase flow of oil and gas,it is necessary to design oil drainage holes on the shroud to ensure the smooth discharge of lubricating oil and improve the drag reduction effect.展开更多
BACKGROUND Although gastroscopy is a commonly used diagnostic and therapeutic technique,postoperative gastrointestinal dysfunction is prone to occur.Traditional Chinese medicine theory suggests that postoperative gast...BACKGROUND Although gastroscopy is a commonly used diagnostic and therapeutic technique,postoperative gastrointestinal dysfunction is prone to occur.Traditional Chinese medicine theory suggests that postoperative gastrointestinal disorders are related to spleen and stomach weakness.This study hypothesizes that the combination of acupoint application at the Ziwu Liuzhu acupoint and percutaneous acupoint electrical stimulation can promote postoperative gastrointestinal function recovery and alleviate stress reactions.AIM To investigate the effects of acupoint application of Ziwu Liuzhu combined with percutaneous acupoint electrical stimulation on postoperative gastrointestinal function recovery and stress response in patients undergoing gastrointestinal endoscopy surgery.METHODS A total of 120 patients who underwent gastroscopy surgery were selected and treated between October 2024 and January 2025.This study used a stratified block randomization method,and then allocated groups using computer-generated random number sequences(SAS 9.4 software).The groups were divided into two groups:A control group of 60 patients who received routine postoperative intervention measures,and an observation group of 60 patients who received acupuncture point application combined with transcutaneous acupoint electrical CONCLUSION The combination of percutaneous acupoint electrical stimulation in gastroscopy patients has been demonstrated to be both highly safe and effective.The benefits of this approach include the promotion of postoperative gastrointestinal function,the reduction of stress response,the attainment of optimal results,and the enhancement of patient satisfaction.展开更多
In the scenario of a steam generator tube rupture accident in a lead-cooled fast reactor,secondary circuit subcooled water under high pressure is injected into an ordinary-pressure primary vessel,where a molten lead-b...In the scenario of a steam generator tube rupture accident in a lead-cooled fast reactor,secondary circuit subcooled water under high pressure is injected into an ordinary-pressure primary vessel,where a molten lead-based alloy(typically pure lead or lead-bismuth eutectic(LBE))is used as the coolant.To clarify the pressure build-up characteristics under water-jet injection,this study conducted several experiments by injecting pressurized water into a molten LBE pool at Sun Yat-sen University.To obtain a further understanding,several new experimental parameters were adopted,including the melt temperature,water subcooling,injection pressure,injection duration,and nozzle diameter.Through detailed analyses,it was found that the pressure and temperature during the water-melt interaction exhibited a consistent variation trend with our previous water-droplet injection mode LBE experiment.Similarly,the existence of a steam explosion was confirmed,which typically results in a much stronger pressure build-up.For the non-explosion cases,increasing the injection pressure,melt-pool temperature,nozzle diameter,and water subcooling promoted pressure build-up in the melt pool.However,a limited enhancement effect was observed when increasing the injection duration,which may be owing to the continually rising pressure in the interaction vessel or the isolation effect of the generated steam cavity.Regardless of whether a steam explosion occurred,the calculated mechanical and kinetic energy conversion efficiencies of the melt were relatively small(not exceeding 4.1%and 0.7%,respectively).Moreover,the range of the conversion efficiency was similar to that of previous water-droplet experiments,although the upper limit of the jet mode was slightly lower.展开更多
BACKGROUND Intramuscular corticosteroid injection may cause adverse effects such as dermal and/or subcutaneous atrophy,alopecia,hypopigmentation,and hyperpigmentation.Although cutaneous atrophy can spontaneously resol...BACKGROUND Intramuscular corticosteroid injection may cause adverse effects such as dermal and/or subcutaneous atrophy,alopecia,hypopigmentation,and hyperpigmentation.Although cutaneous atrophy can spontaneously resolve,several treatment options have been suggested for this condition.CASE SUMMARY In this paper,we report a case of corticosteroid injection induced lipoatrophy treated with autologous whole blood(AWB)injection,as the condition had been unresponsive to fractional laser therapy.A 29-year-old female patient visited the dermatology clinic complaining of skin depression on her right buttock area,which had appeared six months earlier.There had been only subtle improvement at the margins after fractional CO_(2) laser treatment;therefore,after obtaining informed consent from the patient,AWB treatment was initiated.One month after the first AWB injection,the size and depth of the lesion had noticeably improved,and a slight improvement was also observed in discoloration.CONCLUSION Close observation is the initial treatment of choice for steroid induced skin atrophy;however,for patients in need of immediate cosmetic improvement,AWB injection may be a safe and cost-effective alternative.展开更多
Chronic migraine is a potentially debilitating condition that can be detrimental to someone’s quality of life. Clinical data has proven OnabotulinumtoxinA (BoNT-A) to be an effective prophylactic treatment for chroni...Chronic migraine is a potentially debilitating condition that can be detrimental to someone’s quality of life. Clinical data has proven OnabotulinumtoxinA (BoNT-A) to be an effective prophylactic treatment for chronic headache types, and it is now regularly employed by headache treatment centers. The PREEMPT injection protocol has become the standard treatment regimen surrounding Botox injections for chronic migraine treatment since it was granted approval by the FDA in 2010. This retrospective chart review of patients treated for chronic migraine at Maine Comprehensive Pain Management in Scarborough, Maine, presents an alteration to the standard PREEMPT injection paradigm that reinforces the efficacy of Botox for chronic migraine treatment. We will discuss our Modified PREEMPT injection paradigm, which yields a positive clinical response rate of 95% of patients achieving at least 50% improvement in their migraine headaches. This appears to be the highest established response rate in the literature to date.展开更多
Using natural gas(NG)as the primary fuel helps alleviate the fossil fuel crisis while reducing engine soot and nitrogen oxide(NO_(X))emissions.In this paper,the influences of a novel split injection concept on an NG h...Using natural gas(NG)as the primary fuel helps alleviate the fossil fuel crisis while reducing engine soot and nitrogen oxide(NO_(X))emissions.In this paper,the influences of a novel split injection concept on an NG high pressure direct injection(HPDI)engine are examined.Four typical split injection strategies,namely split pre-injection of pilot diesel(PD)and NG,split post-injection of PD and NG,split pre-injection of NG,and split post-injection of PD,were developed to investigate the influences on combustion and emissions.Results revealed that split pre injection of NG enhanced the atomization of PD,whereas the split post-injection of NG lowered the temperature in the core region of the PD spray,resulting in the deterioration of combustion.The effect of the split injection strategy on indicated thermal efficiency exceeded 7.5%.Split pre-injection was favorable to enhancing thermal efficiency,whereas split post-injection was not.Ignition delay,combustion duration,and premixed combustion time proportion were affected by injection strategies by 3.8%,50%,and 19.7%,respectively.Split pre-injection increased CH_(4) emission in the exhaust.Split post-injection,especially split post-injection of PD and NG,reduced the unburned CH_(4) emission by approximately 30%.When the split post-injection ratio was less than 30%,the trade-off between NO_(X) and soot was interrupted.The distribution range of hydroxyl radicals was expanded by pre-injection,and NO_(X) was generated in the region where the NG jet hit the wall.This paper provides valuable insights into the optimization of HPDI injection parameters.展开更多
A novel cooperative injection and suction jet was employed in this work to improve the power extraction characteristics of a semi-active flapping airfoil(S-AFA).The combined Taguchi method and numerical simulations wa...A novel cooperative injection and suction jet was employed in this work to improve the power extraction characteristics of a semi-active flapping airfoil(S-AFA).The combined Taguchi method and numerical simulations was used to optimize the characteristic parameters of the cooperative injection and suction jet that affect the power extraction characteristics of the S-AFA.Under the Reynolds number of 6×10^(4)and the pitching axis location at the center of the ellipse airfoil,the effects of jet position,jet width,jet coefficient as well as phase difference between the cooperative injection and suction jet and the active pitching motion on the power extraction characteristics of the S-AFA are systematically examined.It is concluded that the power extraction characteristics of the S-AFA can be enhanced by employing cooperative injection and suction jet.Compared to the S-AFA without jet,the maximum efficiency is increased 11.06%for the S-AFA with optimized cooperative injection and suction jet.The flow structure behavior analysis shows that the vortex strength,the low pressure range in the suction surface of the airfoil as well as the pressure value in the pressure surface of the airfoil are increased due to the cooperative injection and suction jet,and it is why the power extraction characteristics of S-AFA can be improved.展开更多
文摘Characteristics of heat transfer and flow of Newtonian and non-Newtonian fluids through porous walls and in porous media are studied due to their wide range of applications including geothermal reservoirs,heat exchangers,marine propulsion,and aerodynamics.The current study investigates the characteristics of heat transport in a reactive third-grade fluid,moving through permeable parallel plates,with uniform suction/injection velocity.The two permeable,parallel plates are maintained at the same,constant temperature.After being transformed into its dimensionless equivalent,governing equations are solved by employing the Least Squares Method(LSM).The LSM results are further validated with numerical solutions for temperature and velocity.The impact of cross-flow Reynolds number,Peclet number,heat generation parameter,non-Newtonian parameter,and Brinkman number on entropy generation,velocity,temperature,and Bejan number are investigated.Theresults indicate that temperature distribution is significantly influenced by the third-grade fluid parameter.The maximum temperature drops from almost 0.12 to 0.10 as the third-grade fluid parameter increases from0.05 to 0.4.When the cross-flow Reynolds number is raised from 0.05 to 3,the maximum temperature drops from 0.12 to around 0.09.Temperature is strongly influenced by the heat generation parameter.A greater understanding of the thermal characteristics necessary for the design of a variety of systems,such as heat exchangers,marine propulsion,aerodynamic systems,etc.,may be gained from the findings of the current study.
基金the Deanship of Scientific Research,Taif University,KSA[Research Project Number 0-440-6166].
文摘This paper introduces the effect of heat absorption(generation)and suction(injection)on magnetohydrodynamic(MHD)boundary-layer flow of Casson nanofluid(CNF)via a non-linear stretching surface with the viscous dissipation in two dimensions.By utilizing the similarity transformations,the leading PDEs are transformed into a set of ODEs with adequate boundary conditions and then resolved numerically by(4–5)^(th)-order Runge-Kutta Fehlberg procedure based on the shooting technique.Numerical computations are carried out by Maple 15 software.With the support of graphs,the impact of dimensionless control parameters on the nanoparticle concentration profiles,the temperature,and the flow velocity are studied.Other parameters of interest,such as the skin friction coefficient,heat,and mass transport at the diverse situation and dependency of various parameters are inspected through tables and graphs.Additionally,it is verified that the numerical computations with the reported earlier studies are in an excellent approval.It is found that the heat and mass transmit rates are enhanced with the increasing values of the power-index and the suction(blowing)parameter,whilst are reduced with the boosting Casson and the heat absorption(generation)parameters.Also,the drag force coefficient is an increasing function of the powerindex and a reduction function of Casson parameter.
文摘Several new techniques in the field of heat transfer in fluids have opened new avenues for studying the heat transfer effects in nanofluids and thermodynamic flow parameters, leading to novel applications. There have been studies on nanofluids, including metal, ceramic and magnetic nanoparticles mixed with base fluids such as Water, Kerosene, and Ethylene glycol. However, research on fluids employing semiconductor nanoparticles as supplements to base fluids to generate nanofluids and hybrid nanofluids is limited. For the investigation, Gallium nitrite, a binary semiconductor with excellent heat convection, is together with Cu metal nanoparticles and Al<sub>2</sub>O<sub>3</sub> ceramic nanoparticles separately in the base fluid Ethylene glycol (EG) to form hybrid nanofluids. The effects of convective boundary conditions, thermal radiation, heat source/sink, suction/injection, and activation energy on three-dimensional Williamson MHD hybrid nanofluid flow of Cu + GaN + EG, Al<sub>2</sub>O<sub>3</sub> + GaN + EG, and Cu + Al<sub>2</sub>O<sub>3</sub> + EG are investigated on a stretched sheet with porosity. A similarity transformation is performed on the governing equations to transform them into dimensionless ordinary differential equations ODEs. Numerical analysis is carried out in MATLAB utilizing bvp5c and the shooting technique. The variations of velocity, temperature, and concentration profiles as a function of different physical effects are presented graphically with dimensionless parameters and explained the variations scientifically. As varied with different parameters, the values of the Skin-friction coefficient, Nusselt number, and Sherwood number are mentioned in the table.
文摘The aim of this work is to study the effect of non-uniform single and double slot suction/injection into a steady mixed convection boundary layer flow over a vertical cone, while the axis of the cone is inline with the flow. The governing boundary layer equations are transformed into a non-dimensional form by a group of non-similar trans- formations. The resulting coupled non-linear partial differential equations are solved nu- merically by employing the quasi-linearization technique and an implicit finite-difference scheme. Numerical computations are performed for different values of the dimensionless parameters to display the velocity and temperature profiles graphically. Also, numerical results are presented for the skin friction and heat transfer coefficients. Results indicate that the skin friction and heat transfer coefficients increase with non-uniform slot suction, but the effect of non-uniform slot injection is just opposite.
文摘The work presented herein investigates the velocity, heat transfer, Nusselt number and skin friction profiles involved in boundary layer flow past a moving vertical porous plate. Similarity transformations are employed to convert the governing nonlinear unsteady momentum and energy equations from their partial differential equation forms to boundary value ordinary differential equations. The resulting equations are then solved numerically by the Runge-Kutta fourth order method with the help of a shooting technique. Several features of the flow and heat transfer characteristics for different values of problem parameters are analyzed and discussed. These include the effects of the radiation parameter (R), suction and injection parameter (c), Grashof (Gr) and Prandtl (Pr) numbers on the flow and heat profiles. Numerical results show the impact of blowing and sucking as well as radation on boundary layer flows of this type. Both the skin frictions as well as the heat transfer rate are also significantly related to the radiation parameter. For all these cases;the numerical results are found to be in agreement with the physics of the problem.
基金the financial support of National Board for Higher Mathematics(NBHM),DAE,Mumbai,India for pursuing this work.
文摘In this paper,an investigation is made to study the effects of radiation and heat source/sink on the unsteady boundary layerflow and heat transfer past a shrinking sheet with suction/injection.Theflow is permeated by an externally applied magneticfield normal to the plane offlow.The self-similar equations correspond-ing to the velocity and temperaturefields are obtained,and then solved numerically byfinite difference method using quasilinearization technique.The study reveals that the momentum boundary layer thickness increases with increasing unsteadiness and decreases with magneticfield.The thermal boundary layer thickness decreases with Prandtl number,radiation parameter and heat sink parameter,but it increases with heat source parameter.Moreover,increasing unsteadiness,magneticfield strength,radiation and heat sink strength boost the heat transfer.
文摘The present study reveals the effect of nonlinear thermal radiation and magnetic field on a boundary layer flow of a viscous fluid over a nonlinear stretching sheet with suction or an injection. Using suitable similarity transformations, governing partial differential equations were reduced to higher order ordinary differential equations and further these are solved numerically using of Keller-Box method. Effect of flow controlling parameter on velocity, temperature and nanoparticle fluid concentration, local skin friction coefficient, local Nusselt number and local Sherwood numbers are discussed. It is found that the dimensionless velocity decreases and temperature, concentration are increased with the increasing of magnetic parameter. The temperature profile is an increasing function of thermal radiation when it is increasing.
基金gratefully acknowledges the financial support from the National Board for Higher Mathematics(NBHM),DAE,Mumbai,India to pursue this work.
文摘The magnetohydrodynamic(MHD)boundary layer slipflow and solute transfer over a porous plate in the presence of a chemical reaction are investigated.The governing equations were transformed into self-similar ordinary differential equations by adopting the similarity transformation technique.Then the numerical solutions are obtained by a shooting technique using the fourth order Runge-Kutta method.The study reveals that due to the increase in the boundary slip,the concentration decreases and the velocity increases.On the other hand,with an increase in the magneticfield and mass suction,both boundary layer thicknesses decreased.As the Schmidt number and the reaction rate parameter increases,the concentration decreases and the mass transfer increases.
文摘Combined heat and mass transfer on free, forced, and mixed convection flow along a porous wedge with magnetic effect in the presence of chemical reaction is investigated. The flow field characteristics are analyzed by the Runge-Kutta-Gill scheme with the shooting method as well as the local non-similarity method up to the third level of truncation, which are used to reduce the governing partial differential equations into nine ordinary differential equations. The governing boundary layer equations are converted to a dimensionless form by Falkner-Skan transformations. Because of the effect of suction/injection on the wall of the wedge with buoyancy force and variable wall temperature, the flow field is locally non-similar. Numerical calculations up to the third order level of truncation are carried out as a special case for different values of dimensionless parameters. Effects of the magnetic field strength in the presence of chemical reaction with variable wall temperature and concentration on the dimensionless velocity, temperature and concentration profiles are shown graphically.
基金supported by a research grant from the Universiti Kebangsaan Malaysia (Project Code: UKM-GGPM-NBT-080-2010)
文摘An analysis is performed to study the heat transfer characteristics of steady two-dimensional boundary layer flow past a moving permeable flat plate in a nanofluid. The effects of uniform suction and injection on the flow field and heat transfer characteristics are numerically studied by using an implicit finite difference method. It is found that dual solutions exist when the plate and the free stream move in the opposite directions. The results indicate that suction delays the boundary layer separation, while injection accelerates it.
基金financially supported by the National Natural Science Foundation of China(No.51904026)the Fundamental Research Funds for the Central Universities(No.06500108)。
文摘Hydrogen displays the potential to partially replace pulverized coal injection(PCI)in the blast furnace,and it can reduce CO_(2)emissions.In this paper,a three-dimensional mathematical model of hydrogen and pulverized coal co-injection in blast furnace tuyere was established through numerical simulation,and the effect of hydrogen injection and oxygen enrichment interaction on pulverized coal combustion and raceway smelting was investigated.The simulation results indicate that when the coal injection rate decreased from 36 to 30t/h and the hydrogen injection increased from 0 to 3600 m^(3)/h,the CO_(2)emissions decreased from 1860 to 1551 kg/t,which represents a16.6%reduction,and the pulverized coal burnout decreased from 70.1%to 63.7%.The heat released from hydrogen combustion can not only promote the volatilization of pulverized coal but also affect the combustion reaction between volatilization and oxygen,which resulted in a decrease in the temperature at the end of the raceway.Co-injection of hydrogen with PCI increased the wall temperature near the upper half part of the raceway and at the outlet of the tuyere,which required a high cooling efficiency to extend the service life of the blast furnace.The increase in oxygen level compensated for the decreased average temperature in the raceway due to hydrogen injection.The increase in the oxygen content by 3%while maintaining constant hydrogen and PCI injection rates increased the burnout and average raceway temperature by 4.2%and 43 K,respectively.The mole fraction of CO and H_(2) production increased by 0.04 and 0.02,respectively.Burnout can be improved through optimization of the particle size distribution of pulverized coal.
文摘BACKGROUND A total of 100 patients diagnosed with mixed hemorrhoids from October 2022 to September 2023 in our hospital were randomly divided into groups by dice rolling and compared with the efficacy of different treatment options.AIM To analyze the clinical effect and prognosis of mixed hemorrhoids treated with polidocanol injection combined with automatic elastic thread ligation operation(RPH).METHODS A total of 100 patients with mixed hemorrhoids who visited our hospital from October 2022 to September 2023 were selected and randomly divided into the control group(n=50)and the treatment group(n=50)by rolling the dice.The procedure for prolapse and hemorrhoids(PPH)was adopted in the control group,while polidocanol foam injection+RPH was adopted in the treatment group.The therapeutic effects,operation time,wound healing time,hospital stay,pain situation(24 hours post-operative pain score,first defecation pain score),quality of life(QOL),incidence of complications(post-operative hemorrhage,edema,infection),incidence of anal stenosis 3 months post-operatively and recurrence rate 1 year post-operatively of the two groups were compared.RESULTS Compared with the control group,the total effective rate of treatment group was higher,and the difference was significant(P<0.05).The operation time/wound healing time/hospital stay in the treatment group were shorter than those in the control group(P<0.05).The pain scores at 24 hours after operation/first defecation pain score of the treatment group was significantly lower than those in the control group(P<0.05).After surgery,the QOL scores of the two groups decreased,with the treatment group having higher scores than that of the control group(P<0.05).Compared with the control group,the incidence of postoperative complications in the treatment group was lower,and the difference was significant(P<0.05);However,there was no significant difference in the incidence of postoperative bleeding between the two groups(P>0.05);There was no significant difference in the incidence of anal stenosis 3 months after operation and the recurrence rate 1 year after operation between the two groups(P>0.05).CONCLUSION For patients with mixed hemorrhoids,the therapeutic effect achieved by using polidocanol injection combined with RPH was better.The wounds of the patients healed faster,the postoperative pain was milder,QOL improved,and the incidence of complications was lower,and the short-term and long-term prognosis was good.
基金supported by the National Key R&D Program of China(No.2024YFB4206700)the Joint Geological Funds of the National Natural Science Foundation of China(No.U2244223)+5 种基金the China Scholarship Council Program(No.202404910533)the Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030003)the China Geological Survey Project(No.DD20211350)the Key Deployment Program of Chinese Academy of Sciences(Nos.YJKYYQ20190043,ZDBS-LY-DQC003,KFZD-SW-422,and ZDRW-ZS-2021-3-1)the Scientific Research and Technology Development Project of China National Petroleum Corporation(No.2022DJ5503)the Supercomputing Laboratory,IGGCAS.
文摘This study proposes and systematically evaluates an optimized integration of warm surface seawater injection with depressurization for the long-term exploitation of marine natural gas hydrates.By employing comprehensive multiphysics simulations guided by field data from hydrate production tests in the South China Sea,we pinpoint key operational parameters—such as injection rates,depths,and timings—that notably enhance production efficiency.The results indicate that a 3-phase hydrate reservoir transitions from a free-gas-dominated production stage to a hydrate-decomposition-dominated stage.Moderate warm seawater injection supplies additional heat during the hydrate decomposition phase,thereby enhancing stable production;however,excessively high injection rates can impede the depressurization process.Only injection at an appropriate depth simultaneously balances thermal supplementation and the pressure gradient,leading to higher overall productivity.A“depressurization-driven sensible-heat supply window”is introduced,highlighting that timely seawater injection following initial depressurization prolongs reservoir dissociation dynamics.In this study area,commencing seawater injection at 170 d of depressurization proved optimal.This optimized integration leverages clean and renewable thermal energy,providing essential insights into thermal supplementation strategies with significant implications for sustainable,economically feasible,and efficient commercial-scale hydrate production.
基金Supported by National Natural Science Foundation of China(Grant Nos.51175422,61973011)Shaanxi Provincial Natural Science Basic Research Plan of China(Grant No.2022JM-195)+1 种基金Fundamental Research Funds for the Central Universities of Chinathe Research Start-up Funds of Hangzhou International Innovation Institute of Beihang University(Grant No.2024KQ036)。
文摘During high-speed rotation,the surface of aeronautic spiral bevel gears will generate significant pressure and viscous forces,which will cause a certain amount of windage power loss and reduce the efficiency of the transmission system.Based on the computational fluid dynamics,this paper analyzes the windage power loss of a single spiral bevel gear and a spiral bevel gear pair under oil injection lubrication.In addition,the shroud is used to suppress gear windage loss,and the clearance size and opening angle of the designed shroud are optimized.Finally,by comparing and analyzing the experimental results,the following conclusions were obtained:(1)For a single gear,the speed is the most important factor affecting windage loss,followed by the hand of spiral,and rotation direction;(2)For gear pairs,under oil injection lubrication,the input speed has the greatest impact on windage power loss,followed by the influence of oil injection port speed,temperature and oil injection port pressure;(3)Installing a shroud is an effective method to reduce windage power loss;(4)In the pure air phase,the smaller the clearance between the shroud and the gear surface,and the smaller the radial direction between the shroud and the shaft,the better the effect of reducing windage;(5)In the two-phase flow of oil and gas,it is necessary to design oil drainage holes on the shroud to ensure the smooth discharge of lubricating oil and improve the drag reduction effect.
基金Supported by Zhejiang Province Traditional Chinese Medicine Science and Technology Plan Project,No.2023ZL230。
文摘BACKGROUND Although gastroscopy is a commonly used diagnostic and therapeutic technique,postoperative gastrointestinal dysfunction is prone to occur.Traditional Chinese medicine theory suggests that postoperative gastrointestinal disorders are related to spleen and stomach weakness.This study hypothesizes that the combination of acupoint application at the Ziwu Liuzhu acupoint and percutaneous acupoint electrical stimulation can promote postoperative gastrointestinal function recovery and alleviate stress reactions.AIM To investigate the effects of acupoint application of Ziwu Liuzhu combined with percutaneous acupoint electrical stimulation on postoperative gastrointestinal function recovery and stress response in patients undergoing gastrointestinal endoscopy surgery.METHODS A total of 120 patients who underwent gastroscopy surgery were selected and treated between October 2024 and January 2025.This study used a stratified block randomization method,and then allocated groups using computer-generated random number sequences(SAS 9.4 software).The groups were divided into two groups:A control group of 60 patients who received routine postoperative intervention measures,and an observation group of 60 patients who received acupuncture point application combined with transcutaneous acupoint electrical CONCLUSION The combination of percutaneous acupoint electrical stimulation in gastroscopy patients has been demonstrated to be both highly safe and effective.The benefits of this approach include the promotion of postoperative gastrointestinal function,the reduction of stress response,the attainment of optimal results,and the enhancement of patient satisfaction.
基金supported by Basic and Applied Basic research foundation of Guangdong province(Nos.2021A1515010343 and 2022A1515011582)the Science and Technology Program of Guangdong Province(Nos.2021A0505030026 and 2022A0505050029).
文摘In the scenario of a steam generator tube rupture accident in a lead-cooled fast reactor,secondary circuit subcooled water under high pressure is injected into an ordinary-pressure primary vessel,where a molten lead-based alloy(typically pure lead or lead-bismuth eutectic(LBE))is used as the coolant.To clarify the pressure build-up characteristics under water-jet injection,this study conducted several experiments by injecting pressurized water into a molten LBE pool at Sun Yat-sen University.To obtain a further understanding,several new experimental parameters were adopted,including the melt temperature,water subcooling,injection pressure,injection duration,and nozzle diameter.Through detailed analyses,it was found that the pressure and temperature during the water-melt interaction exhibited a consistent variation trend with our previous water-droplet injection mode LBE experiment.Similarly,the existence of a steam explosion was confirmed,which typically results in a much stronger pressure build-up.For the non-explosion cases,increasing the injection pressure,melt-pool temperature,nozzle diameter,and water subcooling promoted pressure build-up in the melt pool.However,a limited enhancement effect was observed when increasing the injection duration,which may be owing to the continually rising pressure in the interaction vessel or the isolation effect of the generated steam cavity.Regardless of whether a steam explosion occurred,the calculated mechanical and kinetic energy conversion efficiencies of the melt were relatively small(not exceeding 4.1%and 0.7%,respectively).Moreover,the range of the conversion efficiency was similar to that of previous water-droplet experiments,although the upper limit of the jet mode was slightly lower.
基金Supported by The New Faculty Research Grant of Pusan National University,2023The Research Grant of the Chungbuk National University in 2023.
文摘BACKGROUND Intramuscular corticosteroid injection may cause adverse effects such as dermal and/or subcutaneous atrophy,alopecia,hypopigmentation,and hyperpigmentation.Although cutaneous atrophy can spontaneously resolve,several treatment options have been suggested for this condition.CASE SUMMARY In this paper,we report a case of corticosteroid injection induced lipoatrophy treated with autologous whole blood(AWB)injection,as the condition had been unresponsive to fractional laser therapy.A 29-year-old female patient visited the dermatology clinic complaining of skin depression on her right buttock area,which had appeared six months earlier.There had been only subtle improvement at the margins after fractional CO_(2) laser treatment;therefore,after obtaining informed consent from the patient,AWB treatment was initiated.One month after the first AWB injection,the size and depth of the lesion had noticeably improved,and a slight improvement was also observed in discoloration.CONCLUSION Close observation is the initial treatment of choice for steroid induced skin atrophy;however,for patients in need of immediate cosmetic improvement,AWB injection may be a safe and cost-effective alternative.
文摘Chronic migraine is a potentially debilitating condition that can be detrimental to someone’s quality of life. Clinical data has proven OnabotulinumtoxinA (BoNT-A) to be an effective prophylactic treatment for chronic headache types, and it is now regularly employed by headache treatment centers. The PREEMPT injection protocol has become the standard treatment regimen surrounding Botox injections for chronic migraine treatment since it was granted approval by the FDA in 2010. This retrospective chart review of patients treated for chronic migraine at Maine Comprehensive Pain Management in Scarborough, Maine, presents an alteration to the standard PREEMPT injection paradigm that reinforces the efficacy of Botox for chronic migraine treatment. We will discuss our Modified PREEMPT injection paradigm, which yields a positive clinical response rate of 95% of patients achieving at least 50% improvement in their migraine headaches. This appears to be the highest established response rate in the literature to date.
基金Supported by the National Natural Science Foundation of China(No.51909154)Shanghai Engineering Research Center of Ship Intelligent Maintenance and Energy Efficiency(No.20DZ2252300).
文摘Using natural gas(NG)as the primary fuel helps alleviate the fossil fuel crisis while reducing engine soot and nitrogen oxide(NO_(X))emissions.In this paper,the influences of a novel split injection concept on an NG high pressure direct injection(HPDI)engine are examined.Four typical split injection strategies,namely split pre-injection of pilot diesel(PD)and NG,split post-injection of PD and NG,split pre-injection of NG,and split post-injection of PD,were developed to investigate the influences on combustion and emissions.Results revealed that split pre injection of NG enhanced the atomization of PD,whereas the split post-injection of NG lowered the temperature in the core region of the PD spray,resulting in the deterioration of combustion.The effect of the split injection strategy on indicated thermal efficiency exceeded 7.5%.Split pre-injection was favorable to enhancing thermal efficiency,whereas split post-injection was not.Ignition delay,combustion duration,and premixed combustion time proportion were affected by injection strategies by 3.8%,50%,and 19.7%,respectively.Split pre-injection increased CH_(4) emission in the exhaust.Split post-injection,especially split post-injection of PD and NG,reduced the unburned CH_(4) emission by approximately 30%.When the split post-injection ratio was less than 30%,the trade-off between NO_(X) and soot was interrupted.The distribution range of hydroxyl radicals was expanded by pre-injection,and NO_(X) was generated in the region where the NG jet hit the wall.This paper provides valuable insights into the optimization of HPDI injection parameters.
基金This work was supported by the National Natural Science Foundation of China(Grants 51975429 and 51705380)the Wuhan Application Foundation Frontier Project(Grant 2019010701011404).
文摘A novel cooperative injection and suction jet was employed in this work to improve the power extraction characteristics of a semi-active flapping airfoil(S-AFA).The combined Taguchi method and numerical simulations was used to optimize the characteristic parameters of the cooperative injection and suction jet that affect the power extraction characteristics of the S-AFA.Under the Reynolds number of 6×10^(4)and the pitching axis location at the center of the ellipse airfoil,the effects of jet position,jet width,jet coefficient as well as phase difference between the cooperative injection and suction jet and the active pitching motion on the power extraction characteristics of the S-AFA are systematically examined.It is concluded that the power extraction characteristics of the S-AFA can be enhanced by employing cooperative injection and suction jet.Compared to the S-AFA without jet,the maximum efficiency is increased 11.06%for the S-AFA with optimized cooperative injection and suction jet.The flow structure behavior analysis shows that the vortex strength,the low pressure range in the suction surface of the airfoil as well as the pressure value in the pressure surface of the airfoil are increased due to the cooperative injection and suction jet,and it is why the power extraction characteristics of S-AFA can be improved.
