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Minimum mass-entransy dissipation profile for one-way isothermal diffusive mass-transfer process with mass-resistance and massleakage

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Science China Technological Sciences 2024年第8期67卷 2427-2435页

作者： CHEN LinGen XIA ShaoJun Institute of Thermal Science and Power Engineering Wuhan Institute of Technology School of Mechanical & Electrical Engineering Wuhan Institute of Technology School of Power Engineering Naval University of Engineering

As a new concept,mass-entransy is one of the twins in the core of entransy *** can describe mass-transfer ability for masstransfer processes（MTPes）,just as thermal-entransy for describing heat-transfer ***,mass-entransy dissipation can be utilized to evaluate the loss of mass-transfer *** mass-entransy dissipation（MMED） is utilized to optimize one-way isothermal diffusive MTPes with mass-leakage and mass-transfer law(g ∝ Δ（c）,where c means concentration).For a given net amount of mass-transferred key components at the low-concentration side,optimality-condition for the MMED of isothermal diffusive MTPes is obtained by using the *** of the amount of mass-transferred and mass-leakage on optimal results are analyzed,and the obtained optimization profiles are compared with those for MTP profiles of constant-concentration-difference（c1-c2=const） and constant-concentration-ratio（c1/c2=const）.The product of square of key-component-concentration（KCC） difference between high-and low-concentration sides and inert component concentration at high-concentration side for the MMED of the MTP with no mass-leakage is a constant,and the optimal relationship of the KCCs between high-and low-concentration sides with mass-leakage is significantly different from the *** mass-leakage is relatively small,the MTP with c1-c2=const strategy is superior to that with c1/c2=const strategy,and the latter is superior to the former with an increase in mass-leakage.A combination of mass-entransy concept,finite-time thermodynamics,and averaged-optimization-method is a meaningful tool for optimizing MTPes.

关键词： diffusive mass-transfer-law mass-leakage one-way isothermal mass-transfer minimum mass-entransy dissipation finite-time thermodynamics averaged-optimization-method

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Consistency of optimizing finite-time Carnot engines with the low-dissipation model in the two-level atomic heat engine

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Communications in Theoretical Physics 2021年第12期73卷 78-85页

作者： Yu-Han Ma C P Sun Hui Dong Graduate School of China Academy of Engineering Physics Beijing 100193China Beijing Computational Science Research Center Beijing 100193China

The efficiency at the maximum power(EMP)for finite-time Carnot engines established with the low-dissipation model,relies significantly on the assumption of the inverse proportion scaling of the irreversible entropy generationΔS^(ir)on the operation timeτ,i.e.ΔS^(ir)∝1/τ.The optimal operation time of the finite-time isothermal process for EMP has to be within the valid regime of the inverse proportion ***,such consistency was not tested due to the unknown coefficient of the 1/τ-*** this paper,we reveal that the optimization of the finite-time two-level atomic Carnot engines with the low-dissipation model is consistent only in the regime ofη_(C)time for EMP obtained with the low-dissipation model is not within the valid regime of the 1/τ-scaling,and the exact EMP of the engine is found to surpass the well-known boundη_(C)=η_(C)/(2-η_(C)).

关键词： finite-time thermodynamics low-dissipation model quantum heat engine efficiency at maximum power irreversible entropy generation

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Thermodynamic Analysis and Experimental Research of Water-Cooled Small Space Thermoelectric Air-Conditioner

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Journal of Thermal Science 2022年第2期31卷 390-406页

作者： JIANG Fan MENG Fankai CHEN Lin’gen CHEN Zhaojun Institute of Thermal Science and Power Engineering Wuhan Institute of TechnologyWuhan 430205China School of Mechanical&Electrical Engineering Wuhan Institute of TechnologyWuhan 430205China College of Power Engineering Naval University of EngineeringWuhan 430033China

This paper aims to find a more general analysis method for the refrigeration performance,and to design a high efficiency modular cooling structure of water-cooled plate.A new analysis method,namely current and refrigeration rate density analysis,is *** general refrigeration performance calculation equations are obtained.A finite-time thermodynamic model of the thermoelectric device is established considering Thomson *** basic structure of water-cooled thermoelectric air-conditioner is designed and the specific calculation method is *** influences of input current density,filling factor and heat transfer conditions on refrigeration performance of the thermoelectric air-conditioner are analyzed,which is compared with refrigeration performance of air-cooled thermoelectric *** results show that the maximum refrigeration rate density of the water-cooled thermoelectric air-conditioner is 8.65 k W/m^(2),and the maximum coefficient of performance(COP)is 2.27 in the case of the cooling temperature differenceΔT=5 *** withΔT=5 K,the maximum refrigeration rate density and the maximum COP ofΔT=15 K decreases by 27.98%and 76.65%,*** the filling factorθ=0.43,the refrigeration rate density and COP are 2.57 k W/m~2 and 1.24,*** experimental device of thermoelectric air-conditioner is established to verify the *** experimental results show that the maximum value of input current and COP is 4 A and 0.95 with the efficient water-cooling method,*** experimental data coincides with the theoretical calculation,which shows the validity of the analysis method and cooling method.

关键词： thermoelectric air-conditioner refrigeration rate density COP finite-time thermodynamics non-equilibrium thermodynamics performance optimization

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Power and efficiency optimizations for an open cycle two-shaft gas turbine power plant

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Propulsion and Power Research 2023年第4期12卷 457-466页

作者： Lingen Chen Huijun Feng Yanlin Ge Shuangshuang Shi Institute of Thermal Science and Power Engineering Wuhan Institute of TechnologyWuhan 430205China Hubei Provincial Engineering Technology Research Center of Green Chemical Equipment Wuhan 430205China School of Mechanical&Electrical Engineering Wuhan Institute of TechnologyWuhan 430205China

In finite-time thermodynamic analyses for various gas turbine cycles,there are two common models:one is closed-cycle model with thermal conductance optimization of heat exchangers,and another is open-cycle model with optimization of pressure drop(PD)*** of optimization also with searching optimal compressor pressure ratio(PR).This paper focuses on an open-cycle model.A two-shaft open-cycle gas turbine power plant(OCGTPP)is modeled in this *** of power output(PP)and thermal conversion efficiency(TCE)are deduced,and these performances are optimized by varying the relative PD and compressor *** results show that there exist the optimal values(0.32 and 14.0)of PD and PR which lead to double maximum dimensionless PP(1.75).There also exists an optimal value(0.38)of area allocation ratio which leads to maximum TCE(0.37).Moreover,the performances of three types of gas turbine cycles,such as one-shaft and two-shaft ones,are *** the relative pressure drop at the compressor inlet is small,the TCE of third cycle is the biggest one;when this pressure drop is large,the PP of second cycle is the biggest *** results herein can be applied to guide the preliminary designs of OCGTPPs.

关键词： Two-shaft gas turbine power plant Efficiency Power Area distribution Pressure drop finite-time thermodynamics

Abstract models for heat engines

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Frontiers of physics 2021年第3期16卷 99-110页

作者： Zhan-Chun Tu Department of Physics Beijing Normal UniversityBeijing100875China

We retrospect three abstract models for heat engines which include a classic abstract model in textbook of thermal physics,a primary abstract model for finite-time heat engines,and a refined abstract model for finite-time heat *** detailed models of heat engines in literature of finite-time thermodynamics may be mapped into the refined abstract *** future developments based on the refined abstract model are also surveyed.

关键词： abstract model heat engine finite-time thermodynamics

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