A Micromachined Combustor and Its Application to Micro Thermoelectric Power Generation

This paper reports a micromachined combustor and its application to micro thermoelectric power generation. The combustor chamber is covered by a ∼1.3μm thick dielectric diaphragm which is supported by a silicon support rim bonded to a glass substrate. The diaphragm is coated with Pt-catalyst and incorporates a heater for ignition. Scaling effects on self-sustained catalytic combustion are investigated for a square combustor chamber. The small size limit for self-sustained combustion at a hydrogen flow rate of ∼3sccm is found to be between 1 to 2mm. Very large temperature gradients can be achieved on diaphragm because of its low thermal conductance and the high combustion temperature. This combustor configuration is used in a micro thermoelectric power generation chip. The output power level of the generator has been measured to be ∼3μW/thermocouple at a hydrogen flow rate of 3.1sccm.