Research of thermal performance of supercritical carbon dioxide in straight pipe casing

Abstract

In order to solve the problems that the irreversible loss existing in the gas cooler has a great influence on its heat transfer performance,in order to improve the thermal performance of the straight tube tube-in-tube gas cooler,the heat transfer process between carbon dioxide and cooling water in supercritical carbon dioxide tube-in-tube gas cooler was studied.By using Fluent software and entropy generation analysis method,the temperature distribution of carbon dioxide and cooling water along the pipe length was obtained throught changing the operating pressure,carbon dioxide mass flow,cooling water mass flow and inlet temperature;according to the entropy generation analysis method of the second law of thermodynamics,the thermodynamic process in the straight pipe casing was calculated,and the entropy generation distribution along the tube length was obtained.The results show that the entropy production along the tube length increases with the increase of pressure;with the increase of carbon dioxide mass flow,the entropy production gradually decreases;with the increase of cooling water mass flow rate,the increase of entropy production is not obvious;with the increase of cooling water inlet temperature,entropy production decreases.The research result may provide some reference for the operation parameters and structure design of CO2 heat pump gas cooler,as well as for the engineering application of CO2 heat pump.

Keywords

• engineering thermodynamics; supercritical carbon dioxide; casing air cooler; numerical simulation; entropy production analysis; thermal performance