Abstract: The effect of heat transfer caused by plateau environment in vehicle heat exchanger was investigated. The heat transfer equation for heat exchanger was modified by introducing air parameters at different altitudes. A heat transfer modeling approach for vehicle heat exchanger was proposed by using the thermal network method. The heat transfer effect of the plateau and the flow state of fluid medium were analyzed in the vehicle heat exchanger by using the simulation software FlowMaster. Simulation results show that the decrease of pressure and density of air in altitude was the primary cause to heat transfer ability. With the altitude increasing and airflow velocity decreasing, the Re of airflow decreased while the flow state of air in the channel changed from turbulence to laminar state, therefor the convective heat transfer strength declined; and the heat transfer coefficient and the heat transfer ability of heat exchanger both decreased. With every 1 000 m rising in altitude, the heat transfer coefficients of air side and the heat emission of heat exchanger declined by 9.5% and 9.0% respectively.

Key words: heat exchanger, plateau, thermal network method, heat transfer, simulation