Thermal Management System Design And Simulation Study Of PEMFC Engine

Thermal management is critical for automobile fuel economy and safety, as well as environmental conservation. It is a main technical barrier of automobile R&D. Especially for low temperature FC vehicle, because of its low operating temperature, its heat loads can double that of a normal automobile with equivalent power, which makes higher demands on the design of thermal management system. In this paper, some researches on the thermal management of proton exchange membrane fuel cell (PEMFC) engine, such as, design of thermal management system, experiment and simulating technology are done.Based on the analysis of the temperature characteristic of FC stack, the approach to heat transfer of stack is designed. The emphasis is that reduces flow resistance and lowers the temperature gradient of stack. At the same time, the thermal management system of PEMFC engine is designed. The emphasis is that the heat generated must be discharged quickly to maintain its isothermal operation. Then, based on the experiment, the effect of airflow rate and water flow rate on the performance of stack is discussed. Lastly, according to the maximal stack output power, the maximal water flow rate is calculated, which provides a theoretical basis for which type's radiators or water pumps are used.With the development of automation technology, it is possible that the stack operating temperature is controlled automatically. At the same time, with the development of computer technology, simulation research on thermal management system of PEMFC engine becomes possible. With the analysis of heat generation and radiation of the PEMFC engine, respective thermodynamics mathematical model and system thermal equilibrium model were established. Then by use of computer simulation software Matlab/Simulink, the system simulation model which is composed by various subsystem models was built. And the temperature control strategy based on fuzzy control method was established. The simulation result basically corresponded to the temperature change tendency of stack practical operating process.Thermal management test-beds provide an important technical method for the performance test of PEMFC stack as well as the research on thermal management system's performance optimization. The automatically controlling strategy for temperature and tap water supplementing and commingling method were adopted, and a thermal management system suitable for fuel cell engine experiment platformwas set up. Mathematical model and arithmetic of the numeric system was developed based on the principle of thermal fluid dynamics.