Development of meso-scale co-fired ceramic tape axisymmetric combustors

Meso-scale combustors for use in small chemical thrusters were fabricated from low temperature co-fired ceramic (LTCC) and high temperature co-fired ceramic (HTCC) tape technology, and operated with gaseous fuels and oxidizers. In contrast to previous research with tape technology where two-dimensional planar geometries have been fabricated, the present combustors were cylindrical axisymmetric. Igniters that consist of metal wires or silver pastes were co-fired with the ceramic bodies. Ignition and combustion phenomena were studied in combustors with different volumes and various fuels (H ₂, CH ₄, C ₂H ₂, and C ₂H ₄) with either oxygen or air. Various injection methods of the reactants were investigated to determine ignition criteria and flame stability. Reliable and restartable ignition was obtained in combustion chambers ranging from 16 to 104 mm ³. Sustained and stable combustion longer than 600 s was achieved with hydrogen and oxygen under a wide range of equivalence ratios ranging from 0.1 to 1.0. Chemical composition analyses from the combustor exhaust plume were performed with a 64-mm ³ combustion chamber. Combustion efficiencies were determined to be higher than 95% for fuel-lean conditions. However, the thermal efficiency of the 64 mm ³ combustor was estimated to be considerably lower at about 40%.