Chraracterization of a Pulsed Catalytic Micro-Combustor Available to Purchase

Experiments have been conducted to determine the effect of operating conditions and design parameters on the performance of a pulsed catalytic micro-combustor. The micro-combustor test rig was designed to simulate the combustor in a prototype version of a solid-piston micro-engine. The performance parameters of interest were the difference between the minimum and maximum catalyst tube temperature and the efficiency with which the chemical energy of the fuel is converted to mechanical work, as defined by the overall system efficiency. The change in the catalyst tube temperature, which is a measure of the mechanical work produced by the expansion of the catalyst tube, was found to decrease with increasing frequency and to increase with increasing duty cycle, velocity, equivalence ratio and combustor diameter. While the overall system efficiency was found to decrease with increasing frequency, duty cycle, velocity, equivalence ratio and combustor diameter. Therefore there is a trade-off between increasing the power output and the efficiency with which that power is produced. The main factor limiting the overall system efficiency was found to be the thermal-to-mechanical efficiency. It was shown that the overall system efficiency can be increased by optimizing the catalyst tube dimensions and by using a material with a larger coefficient of thermal expansion and/or modulus of elasticity. The information obtained from this study will be used to design a new version of the pulsed catalytic micro-combustor with improved power output and overall system efficiency.