Numerical Analysis And Overall Optimization Of Printed Circuit Theat Exchanger

As a new type of high efficiency and compact heat exchanger,printed circuit heat exchanger has small hydraulic diameter and high heat exchange efficiency.It also meets the requirements of high temperature resistance,high pressure resistance,less leakage and compact structure.It is widely used in nuclear engineering,chemical process,refrigeration and air conditioning and other energy fields.Therefore,it has been widely concerned and studied in recent years.The relevant literature shows that the heat transfer and pressure drop performance parameters of printed circuit heat exchanger are related to many factors,such as channel structure,channel layout,working fluid flow and working state.This paper first uses high-temperature helium and supercritical carbon dioxide as the working fluid of the printed circuit heat exchanger to simulate the straight channel model,and the variation rules of relevant performance parameters and fluid flow and heat transfer characteristics are obtained from the simulation data and temperature nephogram,and the measures to improve its heat transfer performance are obtained.At the same time,reducing the inlet temperature of the cold channel can significantly improve the flow and heat transfer performance of the straight channel model.Then based on the research and analysis of the straight channel model,the four Z-shaped channel models with different channel structure are simulated and studied.The variation rules of heat exchange volume per unit volume,pressure drop and various comprehensive performance parameters with mass flow rate are obtained,and under different comprehensive performance evaluation indicators the data parameters of the four flow channels are analyzed and compared,the better flow channel is found;Finally,the printed circuit heat exchanger is applied to the carbon dioxide ice making system,and the thermodynamic analysis and optimization of eight different system cycles are carried out,the variation rules of system performance with environment temperature,isentropic efficiency of expander and other parameters are obtained,and the parameter data which can improve the performance of the unit when it is suitable for ice making conditions are obtained.