In this study,Computational Fluid Dynamics(CFD)together with a component transport model are exploited to investigate the influence of dimensionless parameters,involving the height of the rectifier grid and the instal...In this study,Computational Fluid Dynamics(CFD)together with a component transport model are exploited to investigate the influence of dimensionless parameters,involving the height of the rectifier grid and the installation height of the first catalyst layer,on the flow field and the overall denitration efficiency of a cement kiln’s SCR(Selective catalytic reduction)denitrification reactor.It is shown that accurate numerical results can be obtained by fitting the particle size distribution function to the actual cement kiln fly ash and implementing a non-uniform particle inlet boundary condition.The relative error between denitration efficiency derived from experimental data,numerical simulation,and real-time system pressure drop ranges from 4%to 9%.Optimization of the SCR reactor is achieved when the rectifier grid thickness ratio k/H≥0.030,the rectifier grid height ratio h/H=0.04,and the spacing between the rectifier grid and the first catalyst layer l/H=0.10.Under these conditions,airflow distribution and particle dispersion upstream of the catalyst result in increased denitration efficiencies of 3.21%,3.43%,and 3.27%,respectively,compared to the least favorable operating conditions.展开更多
The rotary gas-gas heat exchanger(GGH)is a vital component in waste heat recovery systems,partic-ularly for Selective Catalytic Reduction(SCR)processes employed in cement kiln operations.This study investigates the th...The rotary gas-gas heat exchanger(GGH)is a vital component in waste heat recovery systems,partic-ularly for Selective Catalytic Reduction(SCR)processes employed in cement kiln operations.This study investigates the thermal performance of a rotary GGH in medium-and low-temperature denitrification systems,using a simplified porous medium model based on its actual internal structure.A porous medium representation is developed from the structural characteristics of the most efficient heat transfer element,and a local thermal non-equilibrium(LTNE)model is employed to capture the distinct thermal behaviors of the solid matrix and gas phase.To account for the rotational dynamics of the system,the multiple reference frame(MRF)approach is adopted.Numerical simulation results exhibit an average error of less than 5%,demonstrating the model’s reliability and predictive accuracy.The temperature distributions of both the metallic heat exchange surfaces and the flue gas are systematically analyzed.Results indicate that the solid and gas phases exhibit significant non-equilibrium thermal behavior.Notably,the circumferential temperature fluctuations of both the heat exchange surfaces and flue gas vary markedly with changes in rotational speed.At low rotational speeds,the temperature non-uniformity coefficient reaches 4.296,while at high speeds it decreases to 0.4813-indicating that lower speeds lead to more pronounced temperature fluctuations.The simulated temperature field patterns are consistent with experimental observations,validating the effectiveness of the modeling approach.展开更多
Pulsed-jet cleaning is recognized as the most efficient method to regenerate bag dust collectors traditionally used in industrial processes to control the emission of particulates.In this study,non-woven needle felt f...Pulsed-jet cleaning is recognized as the most efficient method to regenerate bag dust collectors traditionally used in industrial processes to control the emission of particulates.In this study,non-woven needle felt filter bags with and without a film coating material have been analyzed considering different geometries(different number N of pairs of pleated filter bag sides)in the frame of dedicated low-pressure pulsed-jet cleaning experiments.The flow structure inside the bag and the response characteristics of its wall have also been analyzed numerically through a computational fluid-dynamics/structural-dynamics(CFD-CSD)unidirectional fluid-solid coupling method.As shown by the experiments,the peak pressure(P_(0))on the wall of the filter bag with N=8 and 12 is higher,which indicates dust can be removed more effectively in these cases.The peak pressure on the wall increases first and then decreases along the direction of the bag length,while the peak pressure of the pleated filter bag with nonwoven needled felt film coating is greater than that without film coating.A comprehensive analysis of the time variation of acceleration,deformation,strain,stress and other factors,has led to the conclusion that the pleated filter bag with N=12 would be the optimal choice.展开更多
If a person comes into contact with pathogens on public facilities,there is a threat of contact(skin/wound)infections.More urgently,there are also reports about COVID-19 coronavirus contact infection,which once again ...If a person comes into contact with pathogens on public facilities,there is a threat of contact(skin/wound)infections.More urgently,there are also reports about COVID-19 coronavirus contact infection,which once again reminds that contact infection is a very easily overlooked disease exposure route.Herein,we propose an innovative implantation strategy to fabricate a multi-walled carbon nanotube/polyvinyl alcohol(MWCNT/PVA,MCP)interpenetrating interface to achieve flexibility,anti-damage,and non-contact sensing electronic skin(E-skin).Interestingly,the MCP E-skin had a fascinating non-contact sensing function,which can respond to the finger approaching 0−20 mm through the spatial weak field.This non-contact sensing can be applied urgently to human–machine interactions in public facilities to block pathogen.The scratches of the fruit knife did not damage the MCP E-skin,and can resist chemical corrosion after hydrophobic treatment.In addition,the MCP E-skin was developed to real-time monitor the respiratory and cough for exercise detection and disease diagnosis.Notably,the MCP E-skin has great potential for emergency applications in times of infectious disease pandemics.展开更多
Sphericity is an important indicator of particle flow properties in rotary granulation. Here, a dynamic simulation approach is proposed to study the formation of particle sphericity during agglomeration by investigati...Sphericity is an important indicator of particle flow properties in rotary granulation. Here, a dynamic simulation approach is proposed to study the formation of particle sphericity during agglomeration by investigating both the orbit and attitude of non-spherical particles in a rotary drum. First, geometric crite- ria are presented to substitute a dual-sphere particle model for the commonly encountered ellipsoidal particle model assuming the long radius of the dual-sphere particle is equal to that of the ellipsoidal particle. Next, a discrete element method is applied to calculate the positions and orientations of dual- sphere particles during granulation. The relationship between shape and attitude in the dual-sphere model is then analyzed by comparing the obtained orientation angle-oblateness curves. A conclusion can be drawn that the particle orientation angle decreases with increasing particle oblateness within a certain range.展开更多
In the building environment,PM2.5 seriously affects people’s health and quality of life,so it is necessary to study the particle deposition characteristics.In addition,it is essential for a thorough investigation of ...In the building environment,PM2.5 seriously affects people’s health and quality of life,so it is necessary to study the particle deposition characteristics.In addition,it is essential for a thorough investigation of the dust removal mechanism to understand the non-spherical particles deposition characteristics.The stacking angle experiment was used to calibrate the discrete element simulation parameters.And four simulation methods(CFD-DPM,CFD-DEM,API interface loading drag model based on EDEM software and EDEM simulation)were used to numerically simulate the non-spherical particles deposition characteristics.The optimal simulation method EDEM was applied to study the non-spherical particles deposition characteristics in filter media,which saves the calculation time obviously.On this basis,the particle parameters on the particle deposition characteristics of filter media were investigated.The results show that the deposition rate of non-spherical(special shape)particles with the same volume is basically consistent on the filter media,hence it is more realistic that the dust actual shape is simplified into the triangular-shaped particles.As the particle size increases,the number of deposited particles on the filter media decreases.And the larger the particle size,the more dispersed the distribution.It has a significant impact on the number of particles deposited on the filter media when the particle velocity is 0.1 m/s.The particle deposits to the lower part of the filter media in the form of a parabola and deviates from the outlet seriously at 0.1 m/s.Moreover,it has little effect on the number of particle deposition at the other velocities,and most particles are deposited on the upper part of the filter media with the increase of particle velocity.展开更多
Advanced energy and sensor devices with novel applications(e.g.,mobile equipment,electric vehicles,and medical-healthcare systems)are one of the important foundations of modern intelligent life.However,there are still...Advanced energy and sensor devices with novel applications(e.g.,mobile equipment,electric vehicles,and medical-healthcare systems)are one of the important foundations of modern intelligent life.However,there are still some scientific issues that seriously hinder the further development of devices,including unsustainability,high material cost,complex fabrication process,safety issues,and unsatisfactory performance.Nanocellulose has aroused tremendous attention in recent decades,because of its abundant resources,renewability,degradability,low-cost,and unique physical/chemical properties.These merits make nanocellulose as matrix materials to fabricate advanced functional composites for use in energy-related fields extremely competitive.Here,we comprehensively discuss the recent progress of nanocellulose for emerging energy storage/harvesting and sensor applications.The preparation methodologies of nanocellulose combined with conductive materials are firstly highlighted,including carbon materials,conductive polymers,metal/metal oxide nanoparticles,metal-organic frameworks(MOFs),and covalent organic frameworks(COFs).We then focus on the nanocellulose-based advanced materials for the application in the areas of supercapacitors,lithium-ion batteries,solar cells,triboelectric nanogenerators,moisture-enabled electric generators,and sensors.Lastly,the future research directions of nanocellulose-based functional materials in energy-related devices are presented.展开更多
基金Anhui Province Key Research and Development Plan of the Ecological Environment Project(No.202104i07020016).
文摘In this study,Computational Fluid Dynamics(CFD)together with a component transport model are exploited to investigate the influence of dimensionless parameters,involving the height of the rectifier grid and the installation height of the first catalyst layer,on the flow field and the overall denitration efficiency of a cement kiln’s SCR(Selective catalytic reduction)denitrification reactor.It is shown that accurate numerical results can be obtained by fitting the particle size distribution function to the actual cement kiln fly ash and implementing a non-uniform particle inlet boundary condition.The relative error between denitration efficiency derived from experimental data,numerical simulation,and real-time system pressure drop ranges from 4%to 9%.Optimization of the SCR reactor is achieved when the rectifier grid thickness ratio k/H≥0.030,the rectifier grid height ratio h/H=0.04,and the spacing between the rectifier grid and the first catalyst layer l/H=0.10.Under these conditions,airflow distribution and particle dispersion upstream of the catalyst result in increased denitration efficiencies of 3.21%,3.43%,and 3.27%,respectively,compared to the least favorable operating conditions.
基金supported the Eco-Environment Project of the Key Research and Development Program of Anhui Province(No.202104i07020016).
文摘The rotary gas-gas heat exchanger(GGH)is a vital component in waste heat recovery systems,partic-ularly for Selective Catalytic Reduction(SCR)processes employed in cement kiln operations.This study investigates the thermal performance of a rotary GGH in medium-and low-temperature denitrification systems,using a simplified porous medium model based on its actual internal structure.A porous medium representation is developed from the structural characteristics of the most efficient heat transfer element,and a local thermal non-equilibrium(LTNE)model is employed to capture the distinct thermal behaviors of the solid matrix and gas phase.To account for the rotational dynamics of the system,the multiple reference frame(MRF)approach is adopted.Numerical simulation results exhibit an average error of less than 5%,demonstrating the model’s reliability and predictive accuracy.The temperature distributions of both the metallic heat exchange surfaces and the flue gas are systematically analyzed.Results indicate that the solid and gas phases exhibit significant non-equilibrium thermal behavior.Notably,the circumferential temperature fluctuations of both the heat exchange surfaces and flue gas vary markedly with changes in rotational speed.At low rotational speeds,the temperature non-uniformity coefficient reaches 4.296,while at high speeds it decreases to 0.4813-indicating that lower speeds lead to more pronounced temperature fluctuations.The simulated temperature field patterns are consistent with experimental observations,validating the effectiveness of the modeling approach.
基金This study was financially supported by Anhui Provincial Scientific and Technological Major Project(Grant No.18030801109).
文摘Pulsed-jet cleaning is recognized as the most efficient method to regenerate bag dust collectors traditionally used in industrial processes to control the emission of particulates.In this study,non-woven needle felt filter bags with and without a film coating material have been analyzed considering different geometries(different number N of pairs of pleated filter bag sides)in the frame of dedicated low-pressure pulsed-jet cleaning experiments.The flow structure inside the bag and the response characteristics of its wall have also been analyzed numerically through a computational fluid-dynamics/structural-dynamics(CFD-CSD)unidirectional fluid-solid coupling method.As shown by the experiments,the peak pressure(P_(0))on the wall of the filter bag with N=8 and 12 is higher,which indicates dust can be removed more effectively in these cases.The peak pressure on the wall increases first and then decreases along the direction of the bag length,while the peak pressure of the pleated filter bag with nonwoven needled felt film coating is greater than that without film coating.A comprehensive analysis of the time variation of acceleration,deformation,strain,stress and other factors,has led to the conclusion that the pleated filter bag with N=12 would be the optimal choice.
基金Zhejiang Provincial Natural Science Key Foundation of China(No.LZ20E030003)National Science Foundation of China(No.51673121)+1 种基金Candidates of Young and Middle Aged Academic Leader of Zhejiang Province,the Young Elite Scientists Sponsorship Program by CAST(No.2018QNRC001)Excellent Doctoral Thesis Cultivation Fund(No.2019D01).
文摘If a person comes into contact with pathogens on public facilities,there is a threat of contact(skin/wound)infections.More urgently,there are also reports about COVID-19 coronavirus contact infection,which once again reminds that contact infection is a very easily overlooked disease exposure route.Herein,we propose an innovative implantation strategy to fabricate a multi-walled carbon nanotube/polyvinyl alcohol(MWCNT/PVA,MCP)interpenetrating interface to achieve flexibility,anti-damage,and non-contact sensing electronic skin(E-skin).Interestingly,the MCP E-skin had a fascinating non-contact sensing function,which can respond to the finger approaching 0−20 mm through the spatial weak field.This non-contact sensing can be applied urgently to human–machine interactions in public facilities to block pathogen.The scratches of the fruit knife did not damage the MCP E-skin,and can resist chemical corrosion after hydrophobic treatment.In addition,the MCP E-skin was developed to real-time monitor the respiratory and cough for exercise detection and disease diagnosis.Notably,the MCP E-skin has great potential for emergency applications in times of infectious disease pandemics.
文摘Sphericity is an important indicator of particle flow properties in rotary granulation. Here, a dynamic simulation approach is proposed to study the formation of particle sphericity during agglomeration by investigating both the orbit and attitude of non-spherical particles in a rotary drum. First, geometric crite- ria are presented to substitute a dual-sphere particle model for the commonly encountered ellipsoidal particle model assuming the long radius of the dual-sphere particle is equal to that of the ellipsoidal particle. Next, a discrete element method is applied to calculate the positions and orientations of dual- sphere particles during granulation. The relationship between shape and attitude in the dual-sphere model is then analyzed by comparing the obtained orientation angle-oblateness curves. A conclusion can be drawn that the particle orientation angle decreases with increasing particle oblateness within a certain range.
基金financially supported by Anhui Provincial Scientific and Technological Major Project (No.18030801109).
文摘In the building environment,PM2.5 seriously affects people’s health and quality of life,so it is necessary to study the particle deposition characteristics.In addition,it is essential for a thorough investigation of the dust removal mechanism to understand the non-spherical particles deposition characteristics.The stacking angle experiment was used to calibrate the discrete element simulation parameters.And four simulation methods(CFD-DPM,CFD-DEM,API interface loading drag model based on EDEM software and EDEM simulation)were used to numerically simulate the non-spherical particles deposition characteristics.The optimal simulation method EDEM was applied to study the non-spherical particles deposition characteristics in filter media,which saves the calculation time obviously.On this basis,the particle parameters on the particle deposition characteristics of filter media were investigated.The results show that the deposition rate of non-spherical(special shape)particles with the same volume is basically consistent on the filter media,hence it is more realistic that the dust actual shape is simplified into the triangular-shaped particles.As the particle size increases,the number of deposited particles on the filter media decreases.And the larger the particle size,the more dispersed the distribution.It has a significant impact on the number of particles deposited on the filter media when the particle velocity is 0.1 m/s.The particle deposits to the lower part of the filter media in the form of a parabola and deviates from the outlet seriously at 0.1 m/s.Moreover,it has little effect on the number of particle deposition at the other velocities,and most particles are deposited on the upper part of the filter media with the increase of particle velocity.
基金the Outstanding Youth Project of Zhejiang Provincial Natural Science Foundation(No.LR22E030002)Zhejiang Provincial Natural Science Key Foundation of China(Nos.LZ20E030003 and LY21E030020).
文摘Advanced energy and sensor devices with novel applications(e.g.,mobile equipment,electric vehicles,and medical-healthcare systems)are one of the important foundations of modern intelligent life.However,there are still some scientific issues that seriously hinder the further development of devices,including unsustainability,high material cost,complex fabrication process,safety issues,and unsatisfactory performance.Nanocellulose has aroused tremendous attention in recent decades,because of its abundant resources,renewability,degradability,low-cost,and unique physical/chemical properties.These merits make nanocellulose as matrix materials to fabricate advanced functional composites for use in energy-related fields extremely competitive.Here,we comprehensively discuss the recent progress of nanocellulose for emerging energy storage/harvesting and sensor applications.The preparation methodologies of nanocellulose combined with conductive materials are firstly highlighted,including carbon materials,conductive polymers,metal/metal oxide nanoparticles,metal-organic frameworks(MOFs),and covalent organic frameworks(COFs).We then focus on the nanocellulose-based advanced materials for the application in the areas of supercapacitors,lithium-ion batteries,solar cells,triboelectric nanogenerators,moisture-enabled electric generators,and sensors.Lastly,the future research directions of nanocellulose-based functional materials in energy-related devices are presented.
