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An exploration for the macroscopic physical meaning of entropy

Science china(Technological Sciences) 2010年第7期53卷 1809-1816页

作者： wu jing1 & guo zengyuan2 1 college of energy and power engineering, nanjing university of aeronautics and astronautics, nanjing 210016, china 2 Key Laboratory for Thermal Science and power engineering of Ministry of Education, School of Aerospace, Tsinghua university, Beijing 100084, china college of energy and power engineering Nanjing University of Aeronautics and Astronautics Nanjing China Key Laboratory for Thermal Science and power engineering of Ministry of Education School of Aerospace Tsinghua University Beijing China

The macroscopic physical meaning of entropy is analyzed based on the exergy (availability) of a combined system (a closed system and its environment), which is the maximum amount of useful work obtainable from the system and the environment as the system is brought into equilibrium with the environment. The process the system experiences can be divided in two sequent sub-processes, the process at constant volume, which represents the heat interaction of the system with the environment, and the adiabatic process, which represents the work interaction of the system with the environment. It is shown that the macroscopic physical meaning of entropy is a measure of the unavailable energy of a closed system for doing useful work through heat interaction. This statement is more precise than those reported in prior literature. The unavailability function of a closed system can be defined as T0S and p0V in volume constant process and adiabatic process, respectively. Their changes, that is, AiTgS) and A (p0V) represent the unusable parts of the internal energy of a closed system for doing useful work in corresponding processes. Finally, the relation between Clausius entropy and Boltzmann entropy is discussed based on the comparison of their expressions for absolute entropy.

关键词： entropy macroscopic physical meaning exergy heat interaction

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A comparison of optimization theories for energy conservation in heat exchanger groups

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Science Bulletin 2011年第Z1期 449-454页

作者： CHEN Qun1,2,wu jing3,WANG MoRan4,PAN Ning2 & guo zengyuan1 1 Key Laboratory for Thermal Science and power engineering of Ministry of Education,Department of engineering Mechanics,Tsinghua university,Beijing 100084,china 2 Department of Biological and Agricultural engineering,university of California,Davis CA 95616,USA 3 college of energy and power engineering,nanjing university of aeronautics and astronautics,nanjing 210016,china 4 Earth and Environmental Sciences Division,Los Alamos National Laboratory,Los Alamos NM 87545,USA

In general,thermal processes can be classified into two categories: heat-work conversion processes and heat transfer processes. Correspondingly,the optimization of thermal processes has to have two different criteria:the well known entropy generation minimization method and the recently proposed entransy dissipation maximization method. This study analyzes the thermal issues in a heat exchanger group,and optimizes the unit arrangements under different constraints based on a suitable optimization crite-rion. The result indicates that the principle of minimum entropy generation rate is valid for optimizing heat exchangers in a ther-modynamic cycle with given boundary temperatures. In contrast,the entransy dissipation maximization is more suitable in heat exchanger optimizations involving only heat transfer processes. Furthermore,the entropy generation rate induced by dumping used streams into ambient surroundings has to be taken into account,except for that originating from the hot and cold-ends of heat exchangers,when using the entropy generation minimization to optimize heat exchangers undergoing a thermodynamic cycle.

关键词： heat exchangers optimization criterion entransy dissipation maximization entropy generation minimization

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Conversion potential energy and its application to thermodynamic optimization

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Science china(Technological Sciences) 2012年第8期55卷 2169-2175页

作者： wu jing guo zengyuan college of energy&power engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory for Thermal Science and power engineering of Ministry of Education Department of Engineering MechanicsTsinghua UniversityBeijing 100084China

In general,heat transfers can be classified into two categories according to the purposes of object heating or cooling and the heat to work ***,a new physical quantity,entransy(or potential energy),was proposed to describe the ability of heat transfer with the former *** paper addresses the concept of potential energy in terms of the heat transfer processes for the latter purpose,named the conversion potential *** physical meaning of this newly introduced concept is the potential energy for the heat to work conversion stored in the equivalent mass of heat(thermomass) derived on the basis of the Einstein's special theory of *** dissipation of conversion potential energy occurs during the real irreversible heat to work conversion processes as a measure of the conversion ***,a heat to work conversion problem of a heat exchanger group is provided to show that the minimum conversion potential energy dissipation rate can be used as an optimization criterion for the heat transfer performance with the purpose of the heat to work conversion.

关键词： conversion potential energy entransy optimization exergy thermomass

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A comparison of optimization theories for energy conservation in heat exchanger groups

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Chinese Science Bulletin 2011年第4期56卷 449-454页

作者： CHEN Qun wu jing WANG MoRan PAN Ning guo zengyuan Key Laboratory for Thermal Science and power engineering of Ministry of Education Department of Engineering Mechanics Tsinghua University Beijing 100084 China Department of Biological and Agricultural engineering University of California Davis CA 95616 USA college of energy and power engineering Nanjing University of Aeronautics andAstronautics Nanjing 210016 China Earth and Environmental Sciences Division Los Alamos National Laboratory Los A lamos NM 87545 USA

关键词：冷端换热器优化理论熵产生率节能传热过程热工过程转换过程过程优化

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Prospective study of light dark matter search with a newly proposed DarkSHINE experiment

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Science china(Physics,Mechanics & Astronomy) 2023年第1期66卷 124-138页

作者： jing Chen Ji-Yuan Chen Jun-Feng Chen Xiang Chen Chang-Bo Fu Jun guo Le He Zheng-Ting He Kim Siang Khaw Jia-Lin Li Liang Li Shu Li Meng Lv Dan-Ning Liu Han-Qing Liu Kun Liu Qi-Bin Liu Yang Liu Ze-Jia Lu Cen Mo Si-Yuan Song Xiao-Long Wang Yu-Feng Wang Zhen Wang Zi-Rui Wang Wei-Hao wu Dao Xiang Hai-Jun Yang Jun-Hua Zhang Yu-Lei Zhang Zhi-Yu Zhao Xu-Liang Zhu Chun-Xiang Zhu Yi-Fan Zhu Tsung-DaoLee Institute Shanghai Jiao Tong UniversityShanghai 201210China Institute of Nuclear and Particle Physics School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Key Laboratory for Particle Astrophysics and Cosmology(MOE) Shanghai Key Laboratory for Particle Physics and Cosmology(SKLPPC)Shanghai 200240China Center for High energy Physics Peking UniversityBeijing 10087lChina School of Mechanical and Electronic engineering Suzhou UniversitySuzhou 234000China School of aeronautics and astronautics Shanghai Jiao Tong UniversityShanghai 200240China School of Electronics Information and Electrical EngineeringShanghai Jiao Tong UniversityShanghai 200240China R&D Center Shanghai Instituteof CeramicsChinese Academyof SciencesShanghai 20189China Key Laboratory of Nuclear Physics and lon-beam Application(MOE) Fudan UniversityShanghai 200443China Institute of Modern Physics Fudan UniversityShanghai 200443China IKey Laboratory for Laser Plasmas(MOE) School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Zhangjiang Institute for Advanced Study Shanghai JiaoTong UniversityShanghai 200240.China college of Literature Scienceand the ArtsUniversity of MichiganAnn Arbor MI 48109-1040USA Deparment of Physics Swiss Federal Institnute of Technology ZurichZurich 8093Swizerland

Dark photons have been well motivated as strong candidates for dark force carriers and light dark matter in the sub-GeV mass *** with collider experiments,fixed-target experiments provide a complementary approach to searching for dark photons,particularly in the lower mass *** have studied the physics potential of the electron-on-target experiment based on the Shanghai SHINE facility,which provides 10 MHz single electron beam at 8 GeV *** analysis focuses on dark photons being produced via electron and nucleon interaction and then decays to dark matter candidates,which escape detection as missing momentum in the *** experiment takes advantage of using missing momentum to enhance signal versus background separation *** this study,signal samples as a function of dark photon mass and an inclusive background sample with 2.5 billion events are simulated with *** better background estimates,major rare background processes have also been *** paper presents the experiment and detector design,signal and background simulations,analysis strategy,and the prospective study of the experiment *** 9×10^(14) electron-on-target events(about three years running),this experiment is expected to rule out most of the sensitive regions predicted by popular dark photon models.

关键词： dark matter dark photon electron-on-target experiment

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