Thermal and Acoustic Performance of Al₂O₃, MgO–ZrO₂, and SiC Porous Media in a Flow-Stabilized Heterogeneous Combustor

Abstract

A comparative analysis of performance of three different porous ceramic materials used as a flame-contained media within a flow-stabilized combustor is presented within this work. The experiments were performed at a constant air flow rate and variable methane flow rates. α-Al2O3, MgO–ZrO2, and SiC highly porous ceramics were used as the porous media. All three porous media used in the study had equal dimensions and porosity and were located in the same fixed position within the combustion chamber. Characterization of the structure of porous media before experimentation was performed using multiple methods. During combustor operation, temperature profiles were collected along with optical and acoustic emissions and correlated with the composition of the gaseous methane/air mixtures. It was found that, while SiC enables the highest temperatures within the combustion chamber at higher equivalence ratios, the ionically conducting MgO–ZrO2 porous media greatly expands the lean limit of combustor operation and is, thus, the preferred porous media material for lower equivalence ratio operation.

A modified zonal method to solve coupled conduction-radiation physics within highly porous large scale digitized cellular porous materials

“…Cellular materials [1] such as open-cell foams, manufactured lattices, fibers felts exhibit interesting properties such as high strength-to-weight ratio, high surface-to-volume ratio, good flow-mixing capacity which make them suitable for several engineering applications. Certain high temperature applications where cellular porous materials are used include solar power power plants [2][3][4], heterogeneous combustion [5], thermal protection systems [6][7][8][9], etc. Note that, for porous samples having mean characteristic size of their constituents greater than a few microns or much greater than the size of thermal radiation can also be refereed as macroporous materials [10,11].…”

Hazardous Gas Detection Sensor Using Broadband Light-Emitting Diode-Based Absorption Spectroscopy for Space Applications

“…As there is negligible gravity-induced buoyancy within spacecraft, the residence time of particles in the air increases 10 ; this enables larger aerosol particulate to form, and the difficulty in distinguishing between smoke and naturally occurring aerosols may lead to false-positive fire detection. 11 Although one approach to minimizing fire potential in space missions and extraterrestrial applications is to use energy conversion techniques that are innately safer such as fuel cells, heterogeneous combustion, photovoltaics, and thermoelectric energy conversion, [12][13][14][15] fire detection and suppression systems will remain necessary. In larger spacecraft or structures intended for long-term human utilization, arrays of hazardous gas detection sensors will be necessary to assist in locating combustion events to enable rapid crew, or automated, response to contain the problem and correct the underlying cause.…”