Power output and efficiency optimization of endoreversible non-isothermal chemical engine via Lewis analogy

Compared with endoreversible heat engine with pure heat transfer and endoreversible isothermal chemical engine with pure mass transfer, endoreversible non-isothermal chemical engine(ENICE) is a more reasonable model of practical mass exchanger,solid device and chemo-electric systems. There exists heat and mass transfer(HMT) simultaneously between working fluid and chemical potential reservoir in ENICE. There is coupled HMT effect that in ENICE should be considered. There are two ways to consider this coupled effect. One is based on Onsager equations, and another is based on Lewis analogy. For the mathematical and physical description of the above HMT process, the model using Onsager equations are more appropriate in the linear HMT region not far from the equilibrium state, while that based on Lewis analogy is more appropriate in nonlinear HMT region far from the equilibrium state. Different from the previous research on the power optimization of ENICEs with Onsager equations,this paper optimizes power and efficiency of ENICE based on Lewis analogy. HMT processes are assumed to obey Newtonian heat transfer law(q∝ΔT, and T is temperature) and Fick’s diffusive mass transfer law(g∝Δc, and c is concentration),respectively. Analytical results of power output and corresponding vector efficiency(ηTand ημ) of ENICE are obtained, which provide important parallel results with those based on Onsager equations. They include special cases for endoreversible Carnot heat engine with q∝ΔT and endoreversible isothermal chemical engine with g∝Δc. Adopting Lewis analogy in the modelling of ENICEs with simultaneous HMT is an important work. It provides important analytical and numerical results different from those with Onsager equations obtained previously and enriches the research contents of FTT. The research results in this paper have a certain guiding significance for the optimal designs of single irreversible NICEs, multistage NICE systems,practical mass exchangers, solid devices, chemo-electric systems, and so on.