Velocity measurement of gas flow using micro piv technique in polymer electrolyte fuel cell

This paper describes a novel velocity measurement technique of the gas flow in micro scale in order to investigate the flow field. In order to visualize the micro gas flow, a fluorescent oil particle as a trace particle suitable for a gas flow was developed. A fluorescent oil particle generator was developed to optimize its diameter, high fluorescent intensity, no-adsorption onto channel surface, density, particle concentration, non-evaporating, electrically neutral, non-toxic, stability with water and no-effect for efficiency of electronic generation. The technique was applied to a flow in a transparent model of PEFC under non-operation initially, which consisted of straight channels of 1.0 mm width and 0.5 mm depth. The velocity distribution of the gas flow successfully measured. The number of vectors was 1516 and the maximum was 0.8 m/sec around the center of the channel at Reynolds number 26. The profile without the near wall region was similar to the theoretical profile obtained using Poiseuille's profile with assumption of non-slip condition at the wall and steady flow. The velocity in the near wall region was slightly large compared with theoretical values. The technique is useful for investigation of flow field in a PEFC with chemical reaction.