Combustion and heat transfer in porous media

Technical Report · Fri Jun 01 04:00:00 EDT 1990

DOI:https://doi.org/10.2172/6284523· OSTI ID:6284523

Sathe, S B; Peck, R E; Tong, T W

The objective of the present study is to generate fundamental knowledge about heat transfer and combustion in porous radiant burners (PRBs) in order to improve their performance. A theoretical heat transfer and combustion model is developed to study the characteristics of PRBs. The model accounts for non-local thermal equilibrium between the solid and gas phases. The solid is assumed to absorb, emit and scatter radiant energy. Combustion is modeled as a one-step global reaction. It is revealed that the flame speed inside the porous medium is enhanced compared to the adiabatic flame speeds due to the higher conductivity of the solid compared to the gas as well as due to radiative preheating of the reactants. The effects of the properties of the porous material on the flame speeds, radiative outputs and efficiencies were investigated. To improve the radiative output from the burner, it is desirable that the porous layer has an optical thickness of about ten. The radiative output and the efficiency is higher for lower scattering albedo. The heat transfer coupling between the solid and gas phases should be high enough to ensure local thermal equilibrium, by choosing a fine porous matrix. Higher solid phase conduction enhances the flame speed and the radiative output. Experiments are performed on a ceramic foam to verify the theoretical findings. The existence of the two stability regions was verified experimentally.

• Research Organization: Arizona State Univ., Tempe, AZ (USA). Dept. of Mechanical and Aerospace Engineering
• Sponsoring Organization: DOE/ER
• DOE Contract Number: FG02-87ER13697
• OSTI ID: 6284523
• Report Number(s): DOE/ER/13697-2; ON: DE91006289
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800 -- Combustion
Pyrolysis
& High-Temperature Chemistry
42 ENGINEERING
420400 -- Engineering-- Heat Transfer & Fluid Flow
421000* -- Engineering-- Combustion Systems
BURNERS
CHEMICAL REACTIONS
COMBUSTION
DOCUMENT TYPES
ENERGY TRANSFER
FLAMES
FLUX DENSITY
HEAT TRANSFER
MATERIALS
MATHEMATICAL MODELS
OXIDATION
PHYSICAL PROPERTIES
POROUS MATERIALS
PROGRESS REPORT
RADIANT FLUX DENSITY
THERMAL CONDUCTIVITY
THERMOCHEMICAL PROCESSES
THERMODYNAMIC PROPERTIES