Analysis And Optimization Of Heat Exchange System On Ship Based On Entransy Theory

As an important part of ship,ship heat exchange system,the improvement of it is an important guarantee for high efficiency and energy saving,while the research on the optimization of the heat transfer system is relatively fragmented.The theory of entransy is a new theory in recent years,which is proposed by academician Guo Zengyuan.It can realize the optimization and analysis of various heat exchange systems.This paper attempts to analyze and optimize the heat exchanger system based on the theory.In view of the high temperature fresh water heat exchange system,the heat transfer optimization model of heat transfer process is established based on the entransy theory.The nonlinear equations of the model are derived and solved.By using the model,the influence of the heat capacity flow and the water temperature at the cylinder liner on the optimum thermal conductivity of the high temperature fresh water heat transfer system is analyzed.The results show that the heat conductivity of the total heat exchanger decreases nonlinearly with the increase of heat capacity flow,and its range of variation decreases gradually;and it increases nonlinearly with the increase of heat load,and its range of variation increases gradually.Here established the optimal heat transfer model considering thermal conversion process of the vapor compression refrigeration cycle of Water chiller of air conditioning system,based on the entransy theory.The corresponding nonlinear equations are derived by using the Lagrange extremum method and solved.The influence of heat load and refrigerant water inlet temperature on the heat transfer of the optimal total heat exchanger was analyzed by using this model.The results show that The thermal conductivity of the total heat exchanger increases nonlinearly with the increase of the cooling load with increasing range;and it decreases nonlinearly with the increase of inlet temperature of refrigerant water with deceasing range.At the end,The heat transfer optimization analysis of a steam compression chiller connected in parallel with several evaporators in a ship cold storage is carried out.Based on entransy theory,here an optimization model and a set of nonlinear equations for evaporating compression refrigeration cycle with multi evaporation temperature are established and solved.The optimum evaporation temperature and refrigerant flow rate of each refrigerator were found.The results show that the total heat conductivity of the total heat exchanger in the optimized cold storage can be reduced by about 2.1%.On the one hand,this dissertation extends the theory of heat transfer analysis and application,which is based on entransy theory.On the other hand,it provides theoretical support for the development of heat exchanger and the optimum design of ship heat transfer system...