Numerical Study on the Transient Preheating Process of a Regenerative Oxidation Bed

The transient preheating process of a regenerative oxidation bed placed in a coal mine methane thermal reverse-flow reactor is numerically investigated in this paper. The regenerative oxidation bed is heated by the burned gas which is generated from a burner and is distributed through manifolds, which is modeled in a three-dimensional, unsteady state and laminar flow system, and is assumed as a semitransparent porous media. Non-local thermal equilibrium between gas and solid is accounted for introducing separate energy equations for two phases in porous media, and the finite volume method is used to solve the radiative transfer equation of the solid phase to calculate the local radiation source term. The calculating results indicate that the regenerative oxidation bed is preheated mainly by the hot gas passing through the manifold, and increasing the inlet mass flow could shorten the time of preheating, specific heat and porosity have a great influence on the heat storage capacity of the regenerative oxidation bed, and the contribution of the solid phase radiation to heat transfer can not be ignored, the temperature is highest in the middle of the regenerative oxidation bed, and it decreases gradually along the direction of height of the regenerative oxidation bed. All these work can help to understand the transient preheating process of a regenerative oxidation bed and the heat transfer phenomena and mechanism during the process.