Recent research on deterministic methods for circulating cooling water systems optimization has been well developed. However, the actual operating conditions of the system are mostly variable, so the system obtained u...Recent research on deterministic methods for circulating cooling water systems optimization has been well developed. However, the actual operating conditions of the system are mostly variable, so the system obtained under deterministic conditions may not be stable and economical. This paper studies the optimization of circulating cooling water systems under uncertain circumstance. To improve the reliability of the system and reduce the water and energy consumption, the influence of different uncertain parameters is taken into consideration. The chance constrained programming method is used to build a model under uncertain conditions, where the confidence level indicates the degree of constraint violation. Probability distribution functions are used to describe the form of uncertain parameters. The objective is to minimize the total cost and obtain the optimal cooling network configuration simultaneously.An algorithm based on Monte Carlo method is proposed, and GAMS software is used to solve the mixed integer nonlinear programming model. A case is optimized to verify the validity of the model. Compared with the deterministic optimization method, the results show that when considering the different types of uncertain parameters, a system with better economy and reliability can be obtained(total cost can be reduced at least 2%).展开更多
A combined process was developed to inhibit the corrosion both in the pipeline of reclaimed water supplies（PRWS） and in downstream recirculating cooling water systems（RCWS）using the reclaimed water as makeup. Hydr...A combined process was developed to inhibit the corrosion both in the pipeline of reclaimed water supplies（PRWS） and in downstream recirculating cooling water systems（RCWS）using the reclaimed water as makeup. Hydroxyl carboxylate-based corrosion inhibitors（e.g.,gluconate, citrate, tartrate） and zinc sulfate heptahydrate, which provided Zn^2＋ as a synergistic corrosion inhibition additive, were added prior to the PRWS when the phosphate（which could be utilized as a corrosion inhibitor） content in the reclaimed water was below 1.7 mg/L, and no additional corrosion inhibitors were required for the downstream RCWS.Satisfactory corrosion inhibition was achieved even if the RCWS was operated under the condition of high numbers of concentration cycles. The corrosion inhibition requirement was also met by the appropriate combination of PO4^3- and Zn^2＋ when the phosphate content in the reclaimed water was more than 1.7 mg/L. The process integrated not only water reclamation and reuse, and the operation of a highly concentrated RCWS, but also the comprehensive utilization of phosphate in reclaimed water and the application of non-phosphorus corrosion inhibitors. The proposed process reduced the operating cost of the PRWS and the RCWS, and lowered the environmental hazard caused by the excessive discharge of phosphate. Furthermore, larger amounts of water resources could be conserved as a result.展开更多
Mesoporous SiO_2 microspheres were synthesized using the sol-gel method and were characterized by TEM, FT-IR and BET techniques. The diameter of the microspheres is about 100—150 nm, and the average mesopore diameter...Mesoporous SiO_2 microspheres were synthesized using the sol-gel method and were characterized by TEM, FT-IR and BET techniques. The diameter of the microspheres is about 100—150 nm, and the average mesopore diameter is 2.55 nm, while the specific surface area is 1 088.9 m2/g. Mesoporous SiO_2 microspheres adsorb glutaraldehyde and immobilize laccase by means of the aldehyde group in glutaral which can react with the amidogen of laccase. The immobilization conditions were optimized at a glutaraldehyde concentration of 0.75%, a crosslinking time of 8 h, a laccase concentration of 0.04 L/L and an immobilization time of 10 h. When diesel leakage concentration was 80 mg/L, the highest corrosion inhibition efficiency of immobilized laccase reached 49.23%, which was slightly lower than the corrosion inhibition efficiency of free laccase(59%). The diesel degradation ratio could reach up to 45%. It has been proved that the immobilized laccase could degrade diesel to inhibit corrosion.展开更多
A series of orthogonal array experiments were conducted using carbon source,ammonia nitrogen and total phosphorus(TP)as major influencing factors to investigate the effects of nutrients on biofouling formation and pre...A series of orthogonal array experiments were conducted using carbon source,ammonia nitrogen and total phosphorus(TP)as major influencing factors to investigate the effects of nutrients on biofouling formation and preponderant bacteria diversity in the recirculatiug cooling water system.Carbon source was demonstrated to be the most significant determinant affecting the biofouling formation.A minimum biofouling outcome was obtained when BOD2,NHa+-N and TP were 25,10,and 1 mg/L,respectively.Then the preponderant bacteria strains in biofouling mass under two typical culture conditions(negative and favorable)were identified applying both traditional biochemical methods and further molecular biology technology with phylogenetic affiliation analysis,which indicated that Enterobacteriaceae Enterobacter,Micrococcaceae Staphylococcus,Bacillaceae Bacillus,Enterobacteriaceae Proteus,Neisseriaceae Neisseria and Pseudomonadaceae Pseudomonas were dominant under negative condition,while Enterobacteriaceae Klebsiella,Enterobacteriaceae Enterobacter and Microbacterium-under favorable one.展开更多
Traditional open circulating cooling water systems use a lot of water and electricity to remove waste heat.In coastal areas,closed seawater circulating cooling water systems have been used as an alternative to improve...Traditional open circulating cooling water systems use a lot of water and electricity to remove waste heat.In coastal areas,closed seawater circulating cooling water systems have been used as an alternative to improve cooling efficiency.However,a comprehensive comparison of the design and advantages of the two types of cooling systems is lacking.Also,the best way to match and optimize the seawater system with the circulating water system in the closed seawater circulating cooling water system has not been fully explored.In this paper,a closed seawater cooling system under multiperiod is constructed,taking into account monthly changes in environmental factors.The mixed integer nonlinear programming model is solved by using GAMS software to evaluate and compare the economics and operability of the two cooling schemes.Meanwhile,the matching relationship of the internal subsystems of the closed seawater circulating cooling water system after coupling the air coolers is studied in depth,and the cooling load is allocated reasonably.The cases show that seawater cooling saves 9.22%of circulating water and reduces the total cost by 8.93%compared with cooling tower.The cost of the closed seawater cooling system can be reduced by 24.37%after coupling air coolers,and there is a direct corresponding matching relationship between circulating water and seawater.展开更多
Deep Q Network(DQN)is an efficient model-free optimization method,and has the potential to be used in building cooling water systems.However,due to the high dimension of actions,this method requires a complex neural n...Deep Q Network(DQN)is an efficient model-free optimization method,and has the potential to be used in building cooling water systems.However,due to the high dimension of actions,this method requires a complex neural network.Therefore,both the required number of training samples and the length of convergence period are barriers for real application.Furthermore,penalty function based exploration may lead to unsafe actions,causing the application of this optimization method even more difficult.To solve these problems,an approach to limit the action space within a safe area is proposed in this paper.First of all,the action space for cooling towers and pumps are separated into two sub-regions.Secondly,for each type of equipment,the action space is further divided into safe and unsafe regions.As a result,the convergence speed is significantly improved.Compared with the traditional DQN method in a simulation environment validated by real data,the proposed method is able to save the convergence time by 1 episode(one cooling season).The results in this paper suggest that,the proposed DQN method can achieve a much quicker learning speed without any undesired consequences,and therefore is more suitable to be used in projects without pre-learning stage.展开更多
Cooling water systems(CWSs)are extensively utilized in various industries to eliminate the excess heat and converse energy.Studies on CWSs mainly concentrated on finding the optimal cooler network structure.In additio...Cooling water systems(CWSs)are extensively utilized in various industries to eliminate the excess heat and converse energy.Studies on CWSs mainly concentrated on finding the optimal cooler network structure.In addition,some works also considered the optimal design under varied operation conditions.However,in these works,once the optimal design of the cooler's network is determined,its arrangement remains fixed and cannot be adapted to accommodate diverse operating conditions.In this work,a flexible topology network concept is proposed to make the adjustment of network structure possible under different operation conditions.The CWS with integrated air cooler and flexible topology network has better overall performance,represented by a mixed integer nonlinear programming(MINLP)model that require advanced tools such as GAMS software.Case studies revealed that the proposed methodology can realize better energy-saving performance,and improve the economic performance under varied operation conditions.The impact of critical flexible nodes on system configuration and economy is achieved by sensitivity analysis.展开更多
A novel environmentally friendly type of calcium carbonate, zinc （Ⅱ） and iron （Ⅲ） scale inhibitor Acrylic acidallylpolyethoxy carboxylate copolymer （AA- APEL） was synthesized. The anti-scale property of the AA...A novel environmentally friendly type of calcium carbonate, zinc （Ⅱ） and iron （Ⅲ） scale inhibitor Acrylic acidallylpolyethoxy carboxylate copolymer （AA- APEL） was synthesized. The anti-scale property of the AA-APEL toward CaCO3, zinc （Ⅱ） and iron （Ⅲ） in the artificial cooling water was studied through static scale inhibition tests. The observation shows that both calcium carbonate, zinc （Ⅱ） and iron （Ⅲ） inhibition increase with increasing the dosage of AA-APEL. The effect on formation of CaCO3 was investigated with combination of scanning electronic microscopy （SEM）, transmission electron microscopy （TEM）, X-ray powder diffraction （XRD） analysis and fourier transform infrared spectrometer, respectively. The results showed that the AA-APEL copolymer not only influenced calcium carbonate crystal morphology and crystal size but also the crystallinity. The crystallization of CaCO3 in the absence of inhibitor was rhombohedral calcite crystal, whereas a mixture of calcite with vaterite crystals was found in the presence of the AA- APEL copolymer. Inhibition mechanism is proposed that the interactions between calcium or iron ions and polyethylene glycol （PEG） are the fundamental impetus to restrain the formation of the scale in cooling water systems.展开更多
The water curtain spray system of the ship helps reduce surface thermal load and lowers thermal infrared radiation, notably enhancing the stealth and survivability of naval ships. The performance of the water curtain ...The water curtain spray system of the ship helps reduce surface thermal load and lowers thermal infrared radiation, notably enhancing the stealth and survivability of naval ships. The performance of the water curtain spray system is largely influenced by the density of the nozzles and their installation height. Therefore, a test platform was established to investigate these critical influencing factors, employing an orthogonal design methodology for the experimental study. Specifically, the study evaluated the effects of varying distances to the steel plate target and different injection heights on the cooling performance of the system. Results demonstrate that using one nozzle per 4 square meters of the ship's surface area effectively lowers the surface temperature, bringing it closer to the ambient background temperature. This nozzle configuration creates irregular infrared heat patterns, which complicate the task for infrared detectors to discern the ship's outline, thus enhancing its infrared stealth. Additionally, maintaining the nozzle installation height within 0.6 m to prevent the temperature difference between the steel plate and the background temperature from exceeding 4 K. Moreover, as the infrared imaging distance increases from 3 to 9 m, the temperature difference measured by the thermocouple and the infrared imager increases by 141.27%. Furthermore, with the increase in infrared imaging distance, the infrared temperature of the target steel plate approaches the background temperature, indicating improved detectability. These findings have significantly enhanced the stealth capabilities of naval ships, maximizing their immunity to infrared-guided weapon attacks. Moreover, their importance in improving the survivability of ships on the water surface cannot be underestimated.展开更多
Since the treatment of circulating water will directly affect the discharge of chemical enterprises, the treatment of circulating water is an important link in the development of chemical enterprises, and the cooling ...Since the treatment of circulating water will directly affect the discharge of chemical enterprises, the treatment of circulating water is an important link in the development of chemical enterprises, and the cooling tower is the decisive factor to determine the temperature of circulating water. Therefore, it is necessary to analyze the problems existing in the cooling tower, and put forward corresponding countermeasures for the problems existing in the operation of circulating water cooling tower, so as to explore a reasonable solution.展开更多
3-mm-thick 5083Al-H19 rolled plates were friction stir welded(FSW) at tool rotation rates of 800 and200 rpm with and without additional water cooling. With decreasing the rotation rate and applying water cooling, soft...3-mm-thick 5083Al-H19 rolled plates were friction stir welded(FSW) at tool rotation rates of 800 and200 rpm with and without additional water cooling. With decreasing the rotation rate and applying water cooling, softening in the FSW joint was significantly reduced. At a low rotation rate of 200 rpm with additional water cooling, almost no obvious softening was observed in the FSW joint, and therefore a FSW5083Al-H19 joint with nearly equal strength to the base material(BM) was obtained. Furthermore, the grains in the nugget zone were considerably refined with reducing the heat input and ultrafine equiaxed grains of about 800 nm were obtained in the lowest heat input condition. This work provides an effective method to achieve high property FSW joints of precipitate-hardened and work-hardened Al alloys.展开更多
The effect of Cl^- on the 316L stainless steel in simulated cooling water has been studied using polarization curves, electrochemical impedance spectroscopy （EIS）, Mott- Schottky plot and scanning electron microsco...The effect of Cl^- on the 316L stainless steel in simulated cooling water has been studied using polarization curves, electrochemical impedance spectroscopy （EIS）, Mott- Schottky plot and scanning electron microscopy （SEM） techniques. Cl^- concentrations vary from 200 to 900 mg/L. Results reveal that the corrosion resistance increases with the decrease of Cl^- concentration in simulated cooling water. The increase of Cl^- concentration leads to the shift of the corrosion potential towards the positive direction. Mott-Schottky curves show that in the passive film, Cr2Oa and FeO at the inner layer exhibit P-type but Fe2O3 and CrOa （CrO4^2-） N-type semiconductive properties. The SEM/EDX data demonstrate that elements such as Fe, O, C, Si and Cl as well as the presence of calcium and aluminum are presented on the surface of the metal.展开更多
The influence of temperature, chloride ions and sulfide ions on the anticorrosion behavior of 316L stainless steel in simulated cooling water was studied by electrochemical impedance spectroscopy and anodic polarizati...The influence of temperature, chloride ions and sulfide ions on the anticorrosion behavior of 316L stainless steel in simulated cooling water was studied by electrochemical impedance spectroscopy and anodic polarization curves. The results show that the film resistance increases with the solution temperature but decreases after 8 days’ immersion, which indicates that the film formed at higher temperature has inferior anticorrosion behavior; Chloride ions and sulfide ions have remarkable effects on the electrochemical property of 316L stainless steel in simulated cooling water and the pitting potential declines with the concentration of chloride ions; the passivation current has no obvious effect; the rise of the concentration of sulfide ions obviously increases the passivation current, but the pitting potential changes little, which indicates that the two types of ions may have different effects on destructing passive film of stainless steel. The critical concentration of chloride ions causing anodic potential curve’s change in simulated cooling water is 250 mg/L for 316 L stainless. The effect of sulfide ions on the corrosion resistance behavior of stainless steel is increasing the passivation current density Ip. The addition of 6 mg/L sulfide ions to the solution makes Ip of 316 L increase by 0.5 times.展开更多
A water cooling treatment was applied in the coal-based reduction of high-chromium vanadium and titanium （V-Ti-Cr） iron ore from the Hongge region of Panzhihua, China. Its effects on the metallization ratio （η）, ...A water cooling treatment was applied in the coal-based reduction of high-chromium vanadium and titanium （V-Ti-Cr） iron ore from the Hongge region of Panzhihua, China. Its effects on the metallization ratio （η）, S removal ratio （Rs）, and P removal ratio （Rp） were studied and analyzed on the basis of chemical composition determined via inductively coupled plasma optical emission spectroscopy. The metallic iron particle size and the element distribution of Fe, V, Cr, and Ti in a reduced briquette after water cooling treatment at 1350℃ were determined and observed via scanning electron microscopy. The results show that the water cooling treatment improved the η, Rs, and Rp in the coal-based reduction of V-Ti-Cr iron ore compared to those obtained with a furnace cooling treatment. Meanwhile, the particle size of metallic iron obtained via the water cooling treatment was smaller than that of metallic iron obtained via the furnace cooling treatment; however, the particle size reached 70 μm at 1350℃, which is substantially larger than the minimum particle size required （20 μm） for magnetic separation. Therefore, the water cooling treatment described in this work is a good method for improving the quality of metallic iron in coal-based reduction and it could be applied in the coal-based reduction of V-Ti-Cr iron ore followed by magnetic separation.展开更多
The controlled runout table cooling is essential in determining the final mechanical properties and flatness of steel strip.The heat of a hot steel strip is mainly extracted by cooling water during runout.In order to ...The controlled runout table cooling is essential in determining the final mechanical properties and flatness of steel strip.The heat of a hot steel strip is mainly extracted by cooling water during runout.In order to study the heat transfer by water jet impingement boiling during runout,apilot facility was constructed at the University of British Columbia.On this pilot facility,the water jet impingement tests were carried out under various cooling conditions to investigate the effect of processing parameters,such as cooling water temperature,water jet impingement velocity,initial strip temperature,water flow rate,water nozzle diameter and array of water nozzles,on the heat transfer of heated strip.The results obtained contribute to the optimization of cooling water during runout.展开更多
The STAR-CCM+software is used to investigate the flow inside a cooling water jacket of an in-line six-cylinder diesel engine.The results show that the average flow velocity of the cooling water inside the jacket is 1....The STAR-CCM+software is used to investigate the flow inside a cooling water jacket of an in-line six-cylinder diesel engine.The results show that the average flow velocity of the cooling water inside the jacket is 1.669 m/s while the flow velocity distribution is not uniform for each cylinder.Moreover,the fluid velocity in proximity to the cylinder head is too low,thereby affecting the cooling performances of the water jacket.Two corresponding structural optimization schemes are proposed to mitigate this issue and the post-optimization performances of the water jacket are discussed in detail.展开更多
The slight-alkalization of generator internal cooling water(GICW)is widely used to inhibit the corrosion of hollow copper conductor and thereby ensure the safe operation of the generator.CO_(2) inleakage is increasing...The slight-alkalization of generator internal cooling water(GICW)is widely used to inhibit the corrosion of hollow copper conductor and thereby ensure the safe operation of the generator.CO_(2) inleakage is increasingly identified as a potential security risk for GICW system.In this paper,the influence of CO_(2) inleakage on the slight-alkalization of GICW was theoretically discussed.Based on the equilibriums of the CO_(2)-NaOH-H_(2)O system,CO_(2) inleakage saturation was derived to quantify the amount of the dissolved CO_(2) in GICW.This parameter can be directly calculated with the measured conductivity and the[Na+]of GICW.The influence of CO_(2) inleakage on the slight-alkalization conditioning of GICW and the measurement of its water quality parameters were then analyzed.The more severe the inleakage,the narrower the water quality operation ranges of GICW,resulting in the more difficult the slight-alkalization conditioning of GICW.The temperature calibrations of the conductivity and the pH value of GICW show nonlinear correlations with the amount of CO_(2) inleakage and the NaOH dosage.This study provides insights into the influence of CO_(2) inleakage on the slight-alkalization of GICW,which can serve as the theoretical basis for the actual slight-alkalization when CO_(2) inleakage occurs.展开更多
To obtain the outlet temperature of combustor,a kind of high-temperature and water cooling thermocouple was designed.The main factors affecting the results of thermocouple measurement were analyzed after numerical sim...To obtain the outlet temperature of combustor,a kind of high-temperature and water cooling thermocouple was designed.The main factors affecting the results of thermocouple measurement were analyzed after numerical simulation.Results showed that the high-temperature water cooling thermocouple can achieve high temperature measurement under the condition of 2 400 K.With the increase of the distance between the water cooling structure and the stagnation cover,the temperature measurement result was more accurate,and the increase in the area ratio of the inlet and outlet of the stagnation cover within a reasonable range can make the measurement results more accurate.The surface emissivity of the measuring point had a great influence on the radiation error.The pressure and flow rate of cooling water can be effectively reduced after adding zirconia coating onto the surface of the rake body.展开更多
Hybrid excitation synchronous motor has the advantages of uniform and adjustable electromagnetic field, wide speed range and high power density. It has broad application prospects in new energy electric vehicles, wind...Hybrid excitation synchronous motor has the advantages of uniform and adjustable electromagnetic field, wide speed range and high power density. It has broad application prospects in new energy electric vehicles, wind power generation and other fields. This paper introduces the basic structure of hybrid excitation motor with modular stator, and analyzes the operation principle of hybrid excitation motor. The cooling structure of the water-cooled plate is designed, and the effects of the thickness of the water-cooled plate and the number of water channels in the water-cooled plate on the heat dissipation capacity of the water-cooled plate are analyzed by theoretical and computational fluid dynamics methods. The effects of different water cooling plate structures on water velocity, pressure drop, water pump power consumption and heat dissipation capacity were compared and analyzed. The influence of different inlet flow velocity on the maximum temperature rise of each part of the motor is analyzed, and the temperature of each part of the motor under the optimal water flow is analyzed. The influence of the traditional spiral water jacket cooling structure and the water-cooled plate cooling structure on the maximum temperature rise of the motor components is compared and analyzed. The results show that the water-cooled plate cooling structure is more suitable for the modular stator motor studied in this paper. Based on the water-cooled plate cooling structure, the air-water composite cooling structure is designed, and the effects of the air-water composite cooling structure and the water-cooled plate cooling structure on the maximum temperature rise of each component of the motor are compared and analyzed. The results show that the maximum temperature rise of each component of the motor is reduced under the air-water composite cooling structure.展开更多
Mathematical physics equations are often utilized to describe physical phenomena in various fields of science and engineering.One such equation is the Fourier equation,which is a commonly used and effective method for...Mathematical physics equations are often utilized to describe physical phenomena in various fields of science and engineering.One such equation is the Fourier equation,which is a commonly used and effective method for evaluating the effectiveness of temperature control measures for mass concrete.One important measure for temperature control in mass concrete is the use of cooling water pipes.However,the mismatch of grids between large-scale concrete models and small-scale cooling pipe models can result in a significant waste of calculation time when using the finite element method.Moreover,the temperature of the water in the cooling pipe needs to be iteratively calculated during the thermal transfer process.The substructure method can effectively solve this problem,and it has been validated by scholars.The Abaqus/Python secondary development technology provides engineers with enough flexibility to combine the substructure method with an iteration algorithm,which enables the creation of a parametric modeling calculation for cooling water pipes.This paper proposes such a method,which involves iterating the water pipe boundary and establishing the water pipe unit substructure to numerically simulate the concrete temperature field that contains a cooling water pipe.To verify the feasibility and accuracy of the proposed method,two classic numerical examples were analyzed.The results showed that this method has good applicability in cooling pipe calculations.When the value of the iteration parameterαis 0.4,the boundary temperature of the cooling water pipes can meet the accuracy requirements after 4∼5 iterations,effectively improving the computational efficiency.Overall,this approach provides a useful tool for engineers to analyze the temperature control measures accurately and efficiently for mass concrete,such as cooling water pipes,using Abaqus/Python secondary development.展开更多
基金Financial support from the National Natural Science Foundation of China (22022816, 22078358)。
文摘Recent research on deterministic methods for circulating cooling water systems optimization has been well developed. However, the actual operating conditions of the system are mostly variable, so the system obtained under deterministic conditions may not be stable and economical. This paper studies the optimization of circulating cooling water systems under uncertain circumstance. To improve the reliability of the system and reduce the water and energy consumption, the influence of different uncertain parameters is taken into consideration. The chance constrained programming method is used to build a model under uncertain conditions, where the confidence level indicates the degree of constraint violation. Probability distribution functions are used to describe the form of uncertain parameters. The objective is to minimize the total cost and obtain the optimal cooling network configuration simultaneously.An algorithm based on Monte Carlo method is proposed, and GAMS software is used to solve the mixed integer nonlinear programming model. A case is optimized to verify the validity of the model. Compared with the deterministic optimization method, the results show that when considering the different types of uncertain parameters, a system with better economy and reliability can be obtained(total cost can be reduced at least 2%).
基金supported by the Key Laboratory of Drinking Water Science and Technology, Chinese Academy of Sciences (No. 15Z01KLDWST)the National Natural Science Foundation of China (Nos. 51378491 and 51578533)
文摘A combined process was developed to inhibit the corrosion both in the pipeline of reclaimed water supplies（PRWS） and in downstream recirculating cooling water systems（RCWS）using the reclaimed water as makeup. Hydroxyl carboxylate-based corrosion inhibitors（e.g.,gluconate, citrate, tartrate） and zinc sulfate heptahydrate, which provided Zn^2＋ as a synergistic corrosion inhibition additive, were added prior to the PRWS when the phosphate（which could be utilized as a corrosion inhibitor） content in the reclaimed water was below 1.7 mg/L, and no additional corrosion inhibitors were required for the downstream RCWS.Satisfactory corrosion inhibition was achieved even if the RCWS was operated under the condition of high numbers of concentration cycles. The corrosion inhibition requirement was also met by the appropriate combination of PO4^3- and Zn^2＋ when the phosphate content in the reclaimed water was more than 1.7 mg/L. The process integrated not only water reclamation and reuse, and the operation of a highly concentrated RCWS, but also the comprehensive utilization of phosphate in reclaimed water and the application of non-phosphorus corrosion inhibitors. The proposed process reduced the operating cost of the PRWS and the RCWS, and lowered the environmental hazard caused by the excessive discharge of phosphate. Furthermore, larger amounts of water resources could be conserved as a result.
基金supported by the Foundation for Top Talents Program of China University of Petroleum
文摘Mesoporous SiO_2 microspheres were synthesized using the sol-gel method and were characterized by TEM, FT-IR and BET techniques. The diameter of the microspheres is about 100—150 nm, and the average mesopore diameter is 2.55 nm, while the specific surface area is 1 088.9 m2/g. Mesoporous SiO_2 microspheres adsorb glutaraldehyde and immobilize laccase by means of the aldehyde group in glutaral which can react with the amidogen of laccase. The immobilization conditions were optimized at a glutaraldehyde concentration of 0.75%, a crosslinking time of 8 h, a laccase concentration of 0.04 L/L and an immobilization time of 10 h. When diesel leakage concentration was 80 mg/L, the highest corrosion inhibition efficiency of immobilized laccase reached 49.23%, which was slightly lower than the corrosion inhibition efficiency of free laccase(59%). The diesel degradation ratio could reach up to 45%. It has been proved that the immobilized laccase could degrade diesel to inhibit corrosion.
基金supported by the National Natural Science Foundation of China(No.20707040)the State Key Laboratory of Pollution Control and Resource Reuse Foundation(No.PCRRF08002).
文摘A series of orthogonal array experiments were conducted using carbon source,ammonia nitrogen and total phosphorus(TP)as major influencing factors to investigate the effects of nutrients on biofouling formation and preponderant bacteria diversity in the recirculatiug cooling water system.Carbon source was demonstrated to be the most significant determinant affecting the biofouling formation.A minimum biofouling outcome was obtained when BOD2,NHa+-N and TP were 25,10,and 1 mg/L,respectively.Then the preponderant bacteria strains in biofouling mass under two typical culture conditions(negative and favorable)were identified applying both traditional biochemical methods and further molecular biology technology with phylogenetic affiliation analysis,which indicated that Enterobacteriaceae Enterobacter,Micrococcaceae Staphylococcus,Bacillaceae Bacillus,Enterobacteriaceae Proteus,Neisseriaceae Neisseria and Pseudomonadaceae Pseudomonas were dominant under negative condition,while Enterobacteriaceae Klebsiella,Enterobacteriaceae Enterobacter and Microbacterium-under favorable one.
基金support from the National Natural Science Foundation of China under Grant(Grant Nos.22393954 and 22078358)is gratefully acknowledged.
文摘Traditional open circulating cooling water systems use a lot of water and electricity to remove waste heat.In coastal areas,closed seawater circulating cooling water systems have been used as an alternative to improve cooling efficiency.However,a comprehensive comparison of the design and advantages of the two types of cooling systems is lacking.Also,the best way to match and optimize the seawater system with the circulating water system in the closed seawater circulating cooling water system has not been fully explored.In this paper,a closed seawater cooling system under multiperiod is constructed,taking into account monthly changes in environmental factors.The mixed integer nonlinear programming model is solved by using GAMS software to evaluate and compare the economics and operability of the two cooling schemes.Meanwhile,the matching relationship of the internal subsystems of the closed seawater circulating cooling water system after coupling the air coolers is studied in depth,and the cooling load is allocated reasonably.The cases show that seawater cooling saves 9.22%of circulating water and reduces the total cost by 8.93%compared with cooling tower.The cost of the closed seawater cooling system can be reduced by 24.37%after coupling air coolers,and there is a direct corresponding matching relationship between circulating water and seawater.
文摘Deep Q Network(DQN)is an efficient model-free optimization method,and has the potential to be used in building cooling water systems.However,due to the high dimension of actions,this method requires a complex neural network.Therefore,both the required number of training samples and the length of convergence period are barriers for real application.Furthermore,penalty function based exploration may lead to unsafe actions,causing the application of this optimization method even more difficult.To solve these problems,an approach to limit the action space within a safe area is proposed in this paper.First of all,the action space for cooling towers and pumps are separated into two sub-regions.Secondly,for each type of equipment,the action space is further divided into safe and unsafe regions.As a result,the convergence speed is significantly improved.Compared with the traditional DQN method in a simulation environment validated by real data,the proposed method is able to save the convergence time by 1 episode(one cooling season).The results in this paper suggest that,the proposed DQN method can achieve a much quicker learning speed without any undesired consequences,and therefore is more suitable to be used in projects without pre-learning stage.
基金Financial support from the National Natural Science Foundation of China under Grant(Nos.22022816 and 22078358)
文摘Cooling water systems(CWSs)are extensively utilized in various industries to eliminate the excess heat and converse energy.Studies on CWSs mainly concentrated on finding the optimal cooler network structure.In addition,some works also considered the optimal design under varied operation conditions.However,in these works,once the optimal design of the cooler's network is determined,its arrangement remains fixed and cannot be adapted to accommodate diverse operating conditions.In this work,a flexible topology network concept is proposed to make the adjustment of network structure possible under different operation conditions.The CWS with integrated air cooler and flexible topology network has better overall performance,represented by a mixed integer nonlinear programming(MINLP)model that require advanced tools such as GAMS software.Case studies revealed that the proposed methodology can realize better energy-saving performance,and improve the economic performance under varied operation conditions.The impact of critical flexible nodes on system configuration and economy is achieved by sensitivity analysis.
基金This work was supported by the Prospective Joint Research Project of Jiangsu Province （BY2012196） the National Natural Science Foundation of China （Grant No. 51077013）+3 种基金 Special funds for Jiangsu Province Scientific and Technological Achievements Projects of China （BA2011086） Program for Training of 333 High-Level Talent, Jiangsu Province of China （BRA2010033） Scientific Innovation Research Foundation of College Graduate in Jiangsu Province （CXLX-0134） and The Scientific Research Foundation of Graduate of South-east University （YBJJI110）.
文摘A novel environmentally friendly type of calcium carbonate, zinc （Ⅱ） and iron （Ⅲ） scale inhibitor Acrylic acidallylpolyethoxy carboxylate copolymer （AA- APEL） was synthesized. The anti-scale property of the AA-APEL toward CaCO3, zinc （Ⅱ） and iron （Ⅲ） in the artificial cooling water was studied through static scale inhibition tests. The observation shows that both calcium carbonate, zinc （Ⅱ） and iron （Ⅲ） inhibition increase with increasing the dosage of AA-APEL. The effect on formation of CaCO3 was investigated with combination of scanning electronic microscopy （SEM）, transmission electron microscopy （TEM）, X-ray powder diffraction （XRD） analysis and fourier transform infrared spectrometer, respectively. The results showed that the AA-APEL copolymer not only influenced calcium carbonate crystal morphology and crystal size but also the crystallinity. The crystallization of CaCO3 in the absence of inhibitor was rhombohedral calcite crystal, whereas a mixture of calcite with vaterite crystals was found in the presence of the AA- APEL copolymer. Inhibition mechanism is proposed that the interactions between calcium or iron ions and polyethylene glycol （PEG） are the fundamental impetus to restrain the formation of the scale in cooling water systems.
基金Supported by the Research Fund of Key Laboratory of Aircraft Environment Control and Life Support,MIIT,Nanjing University of Aeronautics and Astronautics (Grant No. KLAECLSE-202201)。
文摘The water curtain spray system of the ship helps reduce surface thermal load and lowers thermal infrared radiation, notably enhancing the stealth and survivability of naval ships. The performance of the water curtain spray system is largely influenced by the density of the nozzles and their installation height. Therefore, a test platform was established to investigate these critical influencing factors, employing an orthogonal design methodology for the experimental study. Specifically, the study evaluated the effects of varying distances to the steel plate target and different injection heights on the cooling performance of the system. Results demonstrate that using one nozzle per 4 square meters of the ship's surface area effectively lowers the surface temperature, bringing it closer to the ambient background temperature. This nozzle configuration creates irregular infrared heat patterns, which complicate the task for infrared detectors to discern the ship's outline, thus enhancing its infrared stealth. Additionally, maintaining the nozzle installation height within 0.6 m to prevent the temperature difference between the steel plate and the background temperature from exceeding 4 K. Moreover, as the infrared imaging distance increases from 3 to 9 m, the temperature difference measured by the thermocouple and the infrared imager increases by 141.27%. Furthermore, with the increase in infrared imaging distance, the infrared temperature of the target steel plate approaches the background temperature, indicating improved detectability. These findings have significantly enhanced the stealth capabilities of naval ships, maximizing their immunity to infrared-guided weapon attacks. Moreover, their importance in improving the survivability of ships on the water surface cannot be underestimated.
文摘Since the treatment of circulating water will directly affect the discharge of chemical enterprises, the treatment of circulating water is an important link in the development of chemical enterprises, and the cooling tower is the decisive factor to determine the temperature of circulating water. Therefore, it is necessary to analyze the problems existing in the cooling tower, and put forward corresponding countermeasures for the problems existing in the operation of circulating water cooling tower, so as to explore a reasonable solution.
基金supported by the National Natural Science Foundation of China under grant Nos. 51301178 and 51331008
文摘3-mm-thick 5083Al-H19 rolled plates were friction stir welded(FSW) at tool rotation rates of 800 and200 rpm with and without additional water cooling. With decreasing the rotation rate and applying water cooling, softening in the FSW joint was significantly reduced. At a low rotation rate of 200 rpm with additional water cooling, almost no obvious softening was observed in the FSW joint, and therefore a FSW5083Al-H19 joint with nearly equal strength to the base material(BM) was obtained. Furthermore, the grains in the nugget zone were considerably refined with reducing the heat input and ultrafine equiaxed grains of about 800 nm were obtained in the lowest heat input condition. This work provides an effective method to achieve high property FSW joints of precipitate-hardened and work-hardened Al alloys.
基金supported by the National Natural Science Foundation of China (No.50871020)Science & Technology Program of Beijing(No.D09030303790901)
文摘The effect of Cl^- on the 316L stainless steel in simulated cooling water has been studied using polarization curves, electrochemical impedance spectroscopy （EIS）, Mott- Schottky plot and scanning electron microscopy （SEM） techniques. Cl^- concentrations vary from 200 to 900 mg/L. Results reveal that the corrosion resistance increases with the decrease of Cl^- concentration in simulated cooling water. The increase of Cl^- concentration leads to the shift of the corrosion potential towards the positive direction. Mott-Schottky curves show that in the passive film, Cr2Oa and FeO at the inner layer exhibit P-type but Fe2O3 and CrOa （CrO4^2-） N-type semiconductive properties. The SEM/EDX data demonstrate that elements such as Fe, O, C, Si and Cl as well as the presence of calcium and aluminum are presented on the surface of the metal.
文摘The influence of temperature, chloride ions and sulfide ions on the anticorrosion behavior of 316L stainless steel in simulated cooling water was studied by electrochemical impedance spectroscopy and anodic polarization curves. The results show that the film resistance increases with the solution temperature but decreases after 8 days’ immersion, which indicates that the film formed at higher temperature has inferior anticorrosion behavior; Chloride ions and sulfide ions have remarkable effects on the electrochemical property of 316L stainless steel in simulated cooling water and the pitting potential declines with the concentration of chloride ions; the passivation current has no obvious effect; the rise of the concentration of sulfide ions obviously increases the passivation current, but the pitting potential changes little, which indicates that the two types of ions may have different effects on destructing passive film of stainless steel. The critical concentration of chloride ions causing anodic potential curve’s change in simulated cooling water is 250 mg/L for 316 L stainless. The effect of sulfide ions on the corrosion resistance behavior of stainless steel is increasing the passivation current density Ip. The addition of 6 mg/L sulfide ions to the solution makes Ip of 316 L increase by 0.5 times.
基金financially supported by the Programs of the National Natural Science Foundation of China(Nos.51604065,51090384,51674084,51174051,and 51574082)the National Basic Research Program of China(No.2013CB632603)+1 种基金the Fundamental Funds for the Central Universities(Nos.150203003 and 150202001)the National Key Technology Research and development Program(No.2015BAB19B02)
文摘A water cooling treatment was applied in the coal-based reduction of high-chromium vanadium and titanium （V-Ti-Cr） iron ore from the Hongge region of Panzhihua, China. Its effects on the metallization ratio （η）, S removal ratio （Rs）, and P removal ratio （Rp） were studied and analyzed on the basis of chemical composition determined via inductively coupled plasma optical emission spectroscopy. The metallic iron particle size and the element distribution of Fe, V, Cr, and Ti in a reduced briquette after water cooling treatment at 1350℃ were determined and observed via scanning electron microscopy. The results show that the water cooling treatment improved the η, Rs, and Rp in the coal-based reduction of V-Ti-Cr iron ore compared to those obtained with a furnace cooling treatment. Meanwhile, the particle size of metallic iron obtained via the water cooling treatment was smaller than that of metallic iron obtained via the furnace cooling treatment; however, the particle size reached 70 μm at 1350℃, which is substantially larger than the minimum particle size required （20 μm） for magnetic separation. Therefore, the water cooling treatment described in this work is a good method for improving the quality of metallic iron in coal-based reduction and it could be applied in the coal-based reduction of V-Ti-Cr iron ore followed by magnetic separation.
文摘The controlled runout table cooling is essential in determining the final mechanical properties and flatness of steel strip.The heat of a hot steel strip is mainly extracted by cooling water during runout.In order to study the heat transfer by water jet impingement boiling during runout,apilot facility was constructed at the University of British Columbia.On this pilot facility,the water jet impingement tests were carried out under various cooling conditions to investigate the effect of processing parameters,such as cooling water temperature,water jet impingement velocity,initial strip temperature,water flow rate,water nozzle diameter and array of water nozzles,on the heat transfer of heated strip.The results obtained contribute to the optimization of cooling water during runout.
文摘The STAR-CCM+software is used to investigate the flow inside a cooling water jacket of an in-line six-cylinder diesel engine.The results show that the average flow velocity of the cooling water inside the jacket is 1.669 m/s while the flow velocity distribution is not uniform for each cylinder.Moreover,the fluid velocity in proximity to the cylinder head is too low,thereby affecting the cooling performances of the water jacket.Two corresponding structural optimization schemes are proposed to mitigate this issue and the post-optimization performances of the water jacket are discussed in detail.
文摘The slight-alkalization of generator internal cooling water(GICW)is widely used to inhibit the corrosion of hollow copper conductor and thereby ensure the safe operation of the generator.CO_(2) inleakage is increasingly identified as a potential security risk for GICW system.In this paper,the influence of CO_(2) inleakage on the slight-alkalization of GICW was theoretically discussed.Based on the equilibriums of the CO_(2)-NaOH-H_(2)O system,CO_(2) inleakage saturation was derived to quantify the amount of the dissolved CO_(2) in GICW.This parameter can be directly calculated with the measured conductivity and the[Na+]of GICW.The influence of CO_(2) inleakage on the slight-alkalization conditioning of GICW and the measurement of its water quality parameters were then analyzed.The more severe the inleakage,the narrower the water quality operation ranges of GICW,resulting in the more difficult the slight-alkalization conditioning of GICW.The temperature calibrations of the conductivity and the pH value of GICW show nonlinear correlations with the amount of CO_(2) inleakage and the NaOH dosage.This study provides insights into the influence of CO_(2) inleakage on the slight-alkalization of GICW,which can serve as the theoretical basis for the actual slight-alkalization when CO_(2) inleakage occurs.
基金National Natural Science Foundation(9174110013) Aviation Power Fund(614B090310)
文摘To obtain the outlet temperature of combustor,a kind of high-temperature and water cooling thermocouple was designed.The main factors affecting the results of thermocouple measurement were analyzed after numerical simulation.Results showed that the high-temperature water cooling thermocouple can achieve high temperature measurement under the condition of 2 400 K.With the increase of the distance between the water cooling structure and the stagnation cover,the temperature measurement result was more accurate,and the increase in the area ratio of the inlet and outlet of the stagnation cover within a reasonable range can make the measurement results more accurate.The surface emissivity of the measuring point had a great influence on the radiation error.The pressure and flow rate of cooling water can be effectively reduced after adding zirconia coating onto the surface of the rake body.
基金supported by the National Natural Science Foundation of China (51907129)Project Supported by Department of Science and Technology of Liaoning Province (2021-MS-236)。
文摘Hybrid excitation synchronous motor has the advantages of uniform and adjustable electromagnetic field, wide speed range and high power density. It has broad application prospects in new energy electric vehicles, wind power generation and other fields. This paper introduces the basic structure of hybrid excitation motor with modular stator, and analyzes the operation principle of hybrid excitation motor. The cooling structure of the water-cooled plate is designed, and the effects of the thickness of the water-cooled plate and the number of water channels in the water-cooled plate on the heat dissipation capacity of the water-cooled plate are analyzed by theoretical and computational fluid dynamics methods. The effects of different water cooling plate structures on water velocity, pressure drop, water pump power consumption and heat dissipation capacity were compared and analyzed. The influence of different inlet flow velocity on the maximum temperature rise of each part of the motor is analyzed, and the temperature of each part of the motor under the optimal water flow is analyzed. The influence of the traditional spiral water jacket cooling structure and the water-cooled plate cooling structure on the maximum temperature rise of the motor components is compared and analyzed. The results show that the water-cooled plate cooling structure is more suitable for the modular stator motor studied in this paper. Based on the water-cooled plate cooling structure, the air-water composite cooling structure is designed, and the effects of the air-water composite cooling structure and the water-cooled plate cooling structure on the maximum temperature rise of each component of the motor are compared and analyzed. The results show that the maximum temperature rise of each component of the motor is reduced under the air-water composite cooling structure.
文摘Mathematical physics equations are often utilized to describe physical phenomena in various fields of science and engineering.One such equation is the Fourier equation,which is a commonly used and effective method for evaluating the effectiveness of temperature control measures for mass concrete.One important measure for temperature control in mass concrete is the use of cooling water pipes.However,the mismatch of grids between large-scale concrete models and small-scale cooling pipe models can result in a significant waste of calculation time when using the finite element method.Moreover,the temperature of the water in the cooling pipe needs to be iteratively calculated during the thermal transfer process.The substructure method can effectively solve this problem,and it has been validated by scholars.The Abaqus/Python secondary development technology provides engineers with enough flexibility to combine the substructure method with an iteration algorithm,which enables the creation of a parametric modeling calculation for cooling water pipes.This paper proposes such a method,which involves iterating the water pipe boundary and establishing the water pipe unit substructure to numerically simulate the concrete temperature field that contains a cooling water pipe.To verify the feasibility and accuracy of the proposed method,two classic numerical examples were analyzed.The results showed that this method has good applicability in cooling pipe calculations.When the value of the iteration parameterαis 0.4,the boundary temperature of the cooling water pipes can meet the accuracy requirements after 4∼5 iterations,effectively improving the computational efficiency.Overall,this approach provides a useful tool for engineers to analyze the temperature control measures accurately and efficiently for mass concrete,such as cooling water pipes,using Abaqus/Python secondary development.
