Aero-Thermodynamic Consideration of Single-Crystal-Silicon Premixed-Fuel Microscale Can Combustor

Abstract

This paper describes the aero-thermodynamic design, microfabrication and combustion test results for a single-crystal-silicon premixed-fuel microscale can combustor. The combustion chamber volume is 277 mm3, and the microscale can combustor was fabricated by silicon bulk micromachining technology. Hydrogen fuel-air premixing was performed in the combustion test. The operation space in which stable combustion occurred was experimentally determined from the combustion temperature and efficiency for various mass flow rates and equivalence ratios. The expression for the combustion efficiency under conditions where the overall rate of heat release is limited by the chemical kinetics was consistent with the burning velocity model. The flame stabilization, the range of equivalence ratios and the maximum air velocity that the combustor can tolerate before flame extinction occurs were in agreement with the well - stirred reactor (WSR) and combustion loading parameter (CLP) models. A proposed aero-thermodynamic design approach based on these three models provides a physical interpretation of the experimental results in the operation space of stable combustion. Furthermore, this approach provides a unified physical interpretation of the stable combustion operation spaces of microscale combustors with various dimensions and configurations. Therefore, it is demonstrated that the proposed aero-thermodynamic approach has an important role in predicting the preliminary aerodynamic design performances of new microscale combustors.