AIR FLOW TRAJECTORY AND SURGE AVOIDANCE OF CENTRIFUGAL COMPRESSOR UNDER VARIABLE PRESSURE OPERATION OF AUTOMOTIVE FUEL CELLS |
J. HAN |
Chungnam National University |
|
|
| |
ABSTRACT |
The compressor of an automotive proton exchange membrane fuel cell requires severe dynamic performance under normal driving patterns. Because the air flow demand of the automotive fuel cell requires steep increase/decrease, it is very important to understand the air flow trajectory of the centrifugal compressor to avoid the compressor surge. In this study, a simulation model of an automotive fuel cell system with a dynamic compressor was developed to investigate the proper trajectory of air flow rate on a performance map of an air compressor. The dynamic response of the compressor shows that the cathode inlet and exit valves have a significant effect on surge evolution. In particular, the results showed that a proper combination of valve opening areas is required to avoid compressor surge. In this study, the original two valve approach was reduced to a single cathode exit valve control with fixed cathode inlet orifice. A surge rejection algorithm was also developed, based on the comparison of surge protection envelope pressure with actual measured pressure. The results show that surge evolution is effectively avoided by controlling the cathode exit valve. |
Key Words:
Air compressor, Proton exchange membrane fuel cell, Automotive, Blow-off valve, Surge control |
|