Heat transfer performances of honeycomb regenerators with square or hexagon cell opening

Honeycomb regenerators with varied cell openings are applied to regenerative combustion systems. A three-dimensional unsteady numerical model, which calculate the gas flow and gas-solid heat transfer in regenerators with square or hexagon cell openings is developed by computational fluid dynamics package, FLUENT. The radiative transfer equation is employed to calculate radiative heat transfer in gas and is added in gas energy conservation equation as a source term. Convection coupled with radiation is used in gas-solid boundary condition. Moreover, temperature-dependent thermal properties of gas and solid are considered in the model. By comparing simulation results with experimental data from the literature, the numerical model is verified. The effects of different cell opening shapes on gas-solid interface heat flux, gas temperature profile and energy recovery ratio are compared. The simulation results show that there is a higher outlet air temperature and energy recovery ratio in square opening cells than hexagon opening cells. Furthermore, the influences of cell opening side length and switching time on air preheating effect and pressure loss are investigated in regenerators with the two different openings.