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| 1 | Optimization for entransy dissipation minimization in heat exchanger显示文摘A common of two-fluid flow heat exchanger, in which the heat transfer between highand low-temperature sides obeys Newton's law [q∝Δ(T)], is studied in this paper. By taking entransy dissipation minimization as optimization objective, the optimum parameter distributions in the heat exchanger are derived by using optimal control theory under the condition of fixed heat load. The condition corresponding to the minimum entransy dissipation is that corresponding to a constant heat flux density. Three kinds of heat exchangers, including parallel flow, condensing flow and counter-flow, are considered, and the results show that only the counter-flow heat exchanger can realize the entransy dissipation minimization in the heat transfer process. The obtained results for entransy dissipation minimization are also compared with those obtained for entropy generation minimization by numerical examples. | XIA ShaoJun CHEN LinGen SUN FengRui | 2009 | Chinese Science Bulletin2009，54，19： | 59 |
| 2 | Entransy dissipation minimization for liquid-solid phase change processes显示文摘The liquid-solid phase change process of a simple one-dimensional slab is studied in this paper.By taking entransy dissipation minimization as optimization objective,the optimal external reservoir temperature profiles are derived by using optimal control theory under the condition of a fixed freezing or melting time.The entransy dissipation corresponding to the optimal heat exchange strategies of minimum entransy dissipation is 8/9 of that corresponding to constant reservoir temperature operations,which is independent of all system parameters.The obtained results for entransy dissipation minimization are also compared with those obtained for the optimal heat exchange strategies of minimum entropy generation and constant reservoir temperature operations by numerical examples.The obtained results can provide some theoretical guidelines for the choice of optimal cooling or heating strategy in practical liquid-solid phase change processes. | XIA ShaoJun,CHEN LinGen & SUN FengRui Postgraduate School,Naval University of Engineering,Wuhan 430033,China | 2010 | Science China(Technological Sciences)2010，53，4： | 41 |
| 3 | Constructal design progress for eight types of heat sinks显示文摘This review paper summarizes constructal design progress performed by the authors for eight types of heat sinks with ten performance indexes being taken as the optimization objectives,respectively,by combining the methods of theoretical analysis and numerical calculation.The eight types of heat sinks are uniform height rectangular fin heat sink,non-uniform height rectangular fin heat sink,inline cylindrical pin-fin heat sink(ICPHS),plate single-row pin fin heat sink(PSRPHS),plate inline pin fin heat sink(PIPHS),plate staggered pin fin heat sink(PSPHS),single-layered microchannel heat sink(SLMCHS)with rectangular cross sections and double-layered microchannel heat sink(DLMCHS)with rectangular cross sections,respectively.And the ten performance indexes are heat transfer rate maximization,maximum thermal resistance minimization,minimization of equivalent thermal resistance which is defined based on the entransy dissipation rate(equivalent thermal resistance for short),field synergy number maximization,entropy generation rate minimization,operation cost minimization,thermo-economic function value minimization,pressure drop minimization,enhanced heat transfer factor maximization and efficiency evaluation criterion number maximization,respectively.The optimal constructs of the eight types of heat sinks with different constraints and based on the different optimization objectives are compared with each other.The results indicated that the optimal constructs mostly are different based on different optimization objectives under the same boundary condition.The optimization objective should be suitable chosen based on the focus when the constructal design for one heat sink is performed.The results obtained herein have some important theoretical significances and application values,and can provide scientific bases and theoretical guidelines for the thermal design of real heat sinks and their applications. | CHEN LinGen YANG AiBo FENG HuiJun GE YanLin XIA ShaoJun | 2020 | Science China(Technological Sciences)2020，63，6： | 25 |
| 4 | The optimal path of piston motion for Otto cycle with linear phenomenological heat transfer law显示文摘An Otto cycle engine with internal and external irreversibilities of friction and heat leakage, in which the heat transfer between the working fluid and the environment obeys linear phenomenological heat transfer law [q ∝△(T -1)], is studied in this paper. The optimal piston motion trajectory for maximizing the work output per cycle is derived for the fixed total cycle time and fuel consumed per cycle. Optimal control theory is applied to determine the optimal piston trajectories for the cases of with and without piston acceleration constraint on each stroke and the optimal distribution of the total cycle time among the strokes. The optimal piston motion with acceleration constraint for each stroke consists of three segments, including initial maximum acceleration and final maximum deceleration boundary segments, respectively. Numerical examples for optimal configuration are provided, and the obtained results are compared with those obtained with Newton’s heat transfer law [q ∝△(T )]. The results also show that optimizing the piston motion can improve power and efficiency of the engine by more than 9%. This is primarily due to the decrease in heat leakage loss on the initial portion of the power stroke. | XIA ShaoJun CHEN LinGen SUN FengRui | 2009 | Science China(Physics,Mechanics & Astronomy)2009，52，5： | 18 |
| 5 | The optimal configuration of reciprocating engine based on maximum entransy loss显示文摘A class of two-heat-reservoir heat engine model with heat leakage,finite heat capacity high-temperature source and infinite heat capacity low-temperature heat sink,is researched with the finite-time thermodynamic theory and the entransy theory.The optimal configuration based on the minimum entropy generation and the maximum entransy loss under the given cycle is searched,which are compared with the optimal configuration based on the maximum output work,and all the heat transfer in the model is assumed to obey the Newton’s law.The results show that,for the infinite heat capacity high-temperature source,the optimal configuration does not change whether heat leakage exists or not;however,for the finite hightemperature reservoir,the optimal configuration is different among which based on the minimum entropy generation,the maximum entransy loss,and the maximum output work when the heat leakage exists. | Aibo Yang Lingen Chen Shaojun Xia Fengrui Sun | 2014 | Chinese Science Bulletin2014，59，17： | 14 |
| 6 | Maximum power output of a class of irreversible non-regeneration heat engines with a non-uniform working fluid and linear phenomenological heat transfer law显示文摘Maximum power output of a class of irreversible non-regeneration heat engines with non-uniform working fluid,in which heat transfers between the working fluid and the heat reservoirs obey the linear phenomenological heat transfer law [q ∝Δ(T-1)],are studied in this paper. Optimal control theory is used to determine the upper bounds of power of the heat engine for the lumped-parameter model and the distributed-parameter model,respectively. The results show that the maximum power output of the heat engine in the distributed-parameter model is less than or equal to that in the lumped-parameter model,which could provide more realistic guidelines for real heat engines. Analytical solutions of the maximum power output are obtained for the irreversible heat engines working between constant temperature reservoirs. For the irreversible heat engine operating between variable temperature reservoirs,a numerical example for the lumped-parameter model is provided by numerical calculation. The effects of changes of reservoir's temperature on the maximum power of the heat engine are analyzed. The obtained results are,in addition,compared with those obtained with Newtonian heat transfer law [q ∝Δ(T)]. | XIA ShaoJun CHEN LinGen SUN FengRui | 2009 | Science China(Physics,Mechanics & Astronomy)2009，52，12： | 13 |
| 7 | Entransy dissipation minimization for a class of one-way isothermal mass transfer processes显示文摘A class of one-way isothermal mass transfer processes with Fick’s diffusive mass transfer law[g ∝Δ(c)]is investigated in this paper.Based on the definition of the mass entransy,the entransy dissipation function which reflects the irreversibility of mass transfer ability loss is derived.The optimal concentration allocations of the key components corresponding to the highand low-concentration sides for the minimum entransy dissipation of the mass transfer process are obtained by applying opti- mal control theory and compared with the strategies of the minimum entropy generation,constant mass transfer flux(constant concentration difference),and constant concentration ratio(constant chemical potential difference).The results are as follows. For the optimal mass transfer strategy of the minimum entransy dissipation,the product of the square of the key component concentration difference between the high-and the low-concentration sides and the inert component concentration at the low-concentration side is a constant,while for that of the minimum entropy generation,the ratio of the square of the key com-ponent concentration difference between the high-and the low-concentration sides to the key component concentration at the low-concentration side is a constant;when the mass transfer process is not involved in energy conversion process,the optimi-zation principle should be the minimum entransy dissipation;the mass transfer strategy of constant concentration difference is superior to that of constant concentration ratio.The results obtained in this paper can provide some theoretical guidelines for optimal designs and operations of practical mass transfer processes. | XIA ShaoJun CHEN LinGen SUN FengRui | 2011 | Science China(Technological Sciences)2011，54，2： | 13 |
| 8 | Performance optimization of a class of combined thermoelectric heating devices显示文摘A detailed model of thermally-driven combined thermoelectric(TE) heating device is established. The device consists of twostage TE heat pump(TTEH) and two-stage TE generator(TTEG) with four external heat exchangers(HEXs). Both internal losses and external heat transfer irreversibilities are considered in the model. The heating capacity and the coefficient of performance(COP) of the device are improved through numerical optimization,which is of great significance to the application of the device. The distribution of the total TE element number among four TE devices and the distribution of the total external heat conductance among the four external HEXs are optimized. The results show that both the reservoir temperatures of TTEG and TTEH have significant influences on the performance and the corresponding optimum parameters of the device. The COP can reach 0.14 after optimization when the temperature difference of heat source is 150 K and the temperature difference of heating is 10 K. | CHEN LinGen MENG FanKai GE YanLin FENG HuiJun XIA ShaoJun | 2020 | Science China(Technological Sciences)2020，63，12： | 10 |
| 9 | Maximum work configurations of finite potential capacity reservoir chemical engines显示文摘An isothermal endoreversible chemical engine operating between the finite potential capacity high-chemical-potential reservoir and the infinite potential capacity low-chemical-potential reservoir has been studied in this work.Optimal control theory was applied to determine the optimal cycle configurations corresponding to the maximum work output per cycle for the fixed total cycle time and a universal mass transfer law.Analyses of special examples showed that the optimal cycle configuration with the mass transfer law g∝△μ,where△μis the chemical potential difference,is an isothermal endoreversible chemical engine cycle,in which the chemical potential(or the concentration) of the key component in the working substance of low-chemical-potential side is a constant,while the chemical potentials(or the concentrations) of the key component in the finite potential capacity high-chemical-potential reservoir and the corresponding side working substance change nonlinearly with time,and the difference of the chemical potentials(or the ratio of the concentrations) of the key component between the high-chemical-potential reservoir and the working substance is a constant.While the optimal cycle configuration with the mass transfer law g∝△μc,where △μc is the concentration difference,is different from that with the mass transfer law g∝△μ significantly.When the high-chemical-potential reservoir is also an infinite potential capacity chemical potential reservoir,the optimal cycle configuration of the isothermal endoreversible chemical engine consists of two constant chemical potential branches and two instantaneous constant mass-flux branches,which is independent of the mass transfer law.The object studied in this paper is general,and the results can provide some guidelines for optimal design and operation of real chemical engines. | Xia, ShaoJun Chen, LinGen Sun, FengRui | 2010 | Science China Chemistry2010，53，5： | 9 |
| 10 | Hamilton-Jacobi-Bellman equations and dynamic programming for power-optimization of a multistage heat engine system with generalized convective heat transfer law显示文摘A multistage endoreversible Carnot heat engine system operating between a finite thermal capacity high-temperature fluid reservoir and an infinite thermal capacity low-temperature environment with generalized convective heat transfer law [q∝(ΔT) m ] is investigated in this paper.Optimal control theory is applied to derive the continuous Hamilton-Jacobi-Bellman (HJB) equations,which determine the optimal fluid temperature configurations for maximum power output under the conditions of fixed initial time and fixed initial temperature of the driving fluid.Based on the universal optimization results,the analytical solution for the Newtonian heat transfer law (m=1) is also obtained.Since there are no analytical solutions for the other heat transfer laws (m≠1),the continuous HJB equations are discretized and dynamic programming algorithm is performed to obtain the complete numerical solutions of the optimization problem.The relationships among the maximum power output of the system,the process period and the fluid temperature are discussed in detail.The results obtained provide some theoretical guidelines for the optimal design and operation of practical energy conversion systems. | XIA ShaoJun CHEN LinGen SUN FengRui | 2011 | Chinese Science Bulletin2011，56，11： | 7 |
| 11 | Optimal Performance Characteristics of Subcritical Simple Irreversible Organic Rankine Cycle显示文摘Based on the theory of finite time thermodynamics, a subcritical simple irreversible organic Rankine cycle(SSIORC) model considering heat transfer loss and internal irreversible losses is established in this paper. The total heat transfer surface area is taken as a constraint, and R245fa is adopted as working fluid of the cycle in the performance optimization. The evaporator heat transfer surface area and mass flow rate of the working fluid are optimized to obtain the maximum power output and thermal efficiency of the SSIORC, respectively. In addition, the influences of the internal irreversibilities on the optimal performances are also investigated. The results show that when the evaporator heat transfer surface area is varied, the relationship between power output and thermal efficiency is a loop-shaped curve, and there exist maximum power output and thermal efficiency points, respectively. However, the two maximum points are very close to each other. When the mass flow rate of the working fluid is varied, the relationship between power output and thermal efficiency is a parabolic-like curve. With the decreases of expander and pump irreversible losses, the performances of the irreversible SSORC are close to those of the endoreversible SSORC with the only loss of heat transfer loss. | CHEN Weijian FENG Huijun CHEN Lingen XIA Shaojun | 2018 | Journal of Thermal Science2018，27，6： | 6 |
| 12 | Iron ores matching analysis and optimization for iron-making system by taking energy consumption,CO2 emission or cost minimization as the objective显示文摘An optimization model for iron-making system covering sinter matching process to blast furnace process is established, in which the energy consumption, CO_2 emission and cost minimizations are taken as optimization objectives. Some key constraints are considered according to practical production experience in the modelling. The combination of linear programming(LP)and nonlinear programming(NLP) methods is applied. The optimal sinter matching scheme under given conditions and the optimization results for different objectives are obtained. Effects of sinter grade and basicity on all the optimal objectives and coke ratio in blast furnace process are analyzed, respectively. The results obtained indicate that compared with the initial values,the energy consumption/CO_2 emission of iron-making system decreases by 2.03% for objectives of energy consumption/CO_2 emission minimizations and 1.89% for the objective of cost minimization, the cost decreases by 17.88% and 18.13%, respectively.All the three criteria decrease with the increasing lump usage, coal powder injection, blast temperature, and decreasing coke ratio for the iron-making system. | SHEN Xun CHEN LinGen XIA ShaoJun QIN XiaoYong XIE ZhiHui | 2017 | Science China(Technological Sciences)2017，60，11： | 4 |
| 13 | Multi-objective optimization for membrane reactor for steam methane reforming heated by molten salt显示文摘A membrane reactor for steam methane reforming heated by molten salt(MS-SMRMR)is studied based on finite time thermodynamics for decreasing carbon emissions and improving hydrogen production rate(HPR).Effects of flow directions of sweep gas and molten salt on MS-SMRMR are researched.Profiles of temperatures,HPR,and local entropy generation rates(EGRs)of MS-SMRMR are analyzed.Hybrid particle swarm optimization algorithm is utilized to obtain the minimum of specific EGR(SEGR),ratio of EGR to HPR.Multi-objective optimization about HPR maximization and EGR minimization is performed by utilizing NSGA-II.The EGR caused by the mass transfer process is the largest among all irreversible processes in the MS-SMRMR.The membrane length should be slightly shorter than the reactor length when the flow direction of sweep gas is different from that of reaction mixture.When flow directions of molten salt and sweep gas are opposite to that of reaction mixture,SEGR is the smallest.Compared with SEGR calculated by utilizing initial parameters,SEGRs after primary,twice and triple optimizations reduce by 1.2%,5.5%and 5.7%,respectively.SEGR can be further decreased by adjusting other operating parameters.Pareto front provides many optimization results,and it contains SEGR minimization.In Pareto front,an optimum decision point is obtained based on decision-making of TOPSIS,and its EGR and HPR,respectively,increase by 7.12%and13.24%,compared with those obtained by using initial parameters.The results have certain theoretical guiding significance for optimization designs of MS-SMRMR. | CHEN LinGen LI PengLei XIA ShaoJun KONG Rui GE YanLin | 2022 | Science China(Technological Sciences)2022，65，6： | 2 |
| 14 | Efficacy of Cigu Xiaozhi pill(慈菇消脂丸) on non-alcoholic steatohepatitis-associated lipoapoptosis through stress-activated c-Jun N-terminal kinase signalling pathway显示文摘OBJECTIVE: To investigate the efficacy of Cigu Xiaozhi pill(慈菇消脂丸, CGXZ) on non-alcoholic steatohepatitis(NASH)-associated lipoapoptosis through the stress-activated c-Jun N-terminal kinase(JNK)/stress-activated protein kinase signalling pathway.METHODS: Sixty male Sprague-Dawley rats were randomly divided into the following groups(10 rats each): blank control, model, low-dose CGXZ,medium-dose CGXZ, high-dose CGXZ, and positive control(treated with SP600125, a JNK inhibitor).The NASH model was established and the histomor-phological characteristics of haematoxylin and eosin-stained liver tissues were examined under a light microscope. Cell apoptosis in liver tissues was assessed via terminal deoxynucleotidyl transferase d UTP nick-end labelling assay. In addition, the m RNA and protein expression levels of p-JNK,p-c-Jun, caspase-8, Fas, and Fas-L were determined via fluorescence-based quantitative real-time PCR,immunohistochemical and Western blot assays.RESULTS: Histopathological examination of the liver showed that the model rats had moderate-to-severe steatosis with infiltration of inflammatory cells as well as significantly higher expression levels of the p-JNK, p-c-Jun, caspase-8, Fas, and Fas-L proteins, compared with those in the blank control group(P < 0.01). Hepatic lobules of the rats in the treatment groups showed significantly reduced vacuolar degeneration and steatosis as well as alleviated inflammatory cell infiltration. The high and medium-dose CGXZ groups exhibited significantly lower m RNA and protein expression levels of p-JNK, p-c-Jun, caspase-8, Fas, and Fas-L, compared with those in the model group(P < 0.05 or P <0.01).CONCLUSION: CGXZ pill inhibited the onset of hepatocyte apoptosis by regulating the expression of p-JNK, p-c-Jun, caspase-8, Fas, and Fas-L, thereby exerting therapeutic effects against NASH. | MA Yanhua YU Chengzu WU Yan HAN Tao YANG Shaojun SHI Xia | 2021 | Journal of Traditional Chinese Medicine2021，41，1： | 2 |
| 15 | Total entropy generation rate minimization configuration of a membrane reactor of methanol synthesis via carbon dioxide hydrogenation显示文摘The total entropy generation rate,internal exergy loss and exergy efficiency of the membrane reactor of methanol synthesis via carbon dioxide hydrogenation are compared,and the results show that the total entropy generation rate minimization is equivalent to the internal exergy loss minimization and the exergy efficiency maximization under the fixed inlet exergy.Therefore,this paper optimizes the membrane reactor with total entropy generation rate minimization as an optimization objective under a fixed methanol production rate.The optimal temperatures curves of exterior walls for three optimal membrane reactors with different boundary conditions are obtained by using optimal control theory and nonlinear programming.The influences of other geometric and operating parameters on optimization results of optimal membrane reactors are analyzed.The results indicate that when inlet temperatures of the reaction mixture and mixture in the permeable tube are unfixed,the optimizing curve of exterior wall temperature makes the total entropy generation rate of membrane reactor reduce by 12.39%compared with the total entropy generation rate of a reference membrane reactor with a linear exterior wall temperature.Decreasing the inlet molar flow rate of sweep gas and gas hourly space velocity and increasing inlet pressure of reaction mixture,the inlet pressure of mixture in the permeable tube and heat transfer coefficients are favorable for decreasing the total entropy generation rate in the membrane reactor.As the porosity of catalyst bed and reactor length increases,the minimum total entropy generation rate decreases first and then increases.From the perspective of engineering application,this paper establishes two membrane reactors(membrane reactor heated by three-stage furnaces of the same length and membrane reactor heated by threestage furnaces of different lengths),respectively.The minimum total entropy generation rates of the two reactors are reduced by11.67%and 11.79%compared with the total entropy generation rate in the reference membrane reactor,respectively.The obtained results are beneficial to the optimal design of energy-efficient membrane reactors. | LI PengLei CHEN LinGen XIA ShaoJun KONG Rui GE YanLin | 2022 | Science China(Technological Sciences)2022，65，3： | 2 |
| 16 | Power-optimization of multistage non-isothermal chemical engine system via Onsager equations,Hamilton-Jacobi-Bellman theory and dynamic programming显示文摘The research on the output rate performance limit of the multi-stage energy conversion system based on modern optimal control theory is one of the hot spots of finite time thermodynamics.The existing research mainly focuses on the multi-stage heat engine system with pure heat transfer and the multi-stage isothermal chemical engine(ICE)system with pure mass transfer,while the multi-stage non ICE system with heat and mass transfer coupling is less involved.A multistage endoreversible non-isothermal chemical engine(ENICE)system with a finite high-chemical-potential(HCP)source(driving fluid)and an infinite low-chemical-potential sink(environment)is researched.The multistage continuous system is treated as infinitesimal ENICEs located continuously.Each infinitesimal ENICE is assumed to be a single-stage ENICE with stationary reservoirs.Extending single-stage results,the maximum power output(MPO)of the multistage system is obtained.Heat and mass transfer processes between the reservoir and working fluid are assumed to obey Onsager equations.For the fixed initial time,fixed initial fluid temperature,and fixed initial concentration of key component(CKC)in the HCP source,continuous and discrete models of the multistage system are optimized.With given initial reservoir temperature,initial CKC,and total process time,the MPO of the multistage ENICE system is optimized with fixed and free final temperature and final concentration.If the final concentration and final temperature are free,there are optimal final temperature and optimal final concentration for the multistage ENICE system to achieve MPO;meanwhile,there are low limit values for final fluid temperature and final concentration.Special cases for multistage endoreversible Carnot heat engines and ICE systems are further obtained.For the model in this paper,the minimum entropy generation objective is not equivalent to MPO objective. | CHEN LinGen XIA ShaoJun | 2023 | Science China(Technological Sciences)2023，66，3： | 1 |
| 17 | Epidemiology of HIV and sexually transmitted infections in China 显示文摘 | Zhang KongAi Ma ShaoJun Xia DongYan | 2004 | Sexual Health2004，16，4： | 1 |
| 18 | Epidemiology of HIV and sexually transmitted infections in China显示文摘 | Zhang Konglai Ma Shaojun Xia Dongyan | 2004 | Sexual Health2004，16，： | 1 |
| 19 | Treatment of organic wastewater containing Cr^3+ by a novel complex process of electrodeposifion and biofilm 显示文摘 | Li Tiancheng Li 'Xingang Feng Xia Jiang Bin Wand Dawei Yuan Shaojun | | Transactions of Tianjin University0，，： | 1 |
| 20 | Epidemiology of HIV and sexually transmitted infections in China 显示文摘 | ZHANG KONGLAI MA SHAOJUN XIA DONGYAN | 2004 | Sexual Health2004，16，4： | 1 |
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