Plasma Heating and Temperature Difference Between Gas Pellets in Packed Bed With Dielectric Barrier Discharge Under Natural Convection Condition

Abstract

A particular phenomenon was found in packed beds with dielectric barrier discharge (DBD): The temperature of the gaseous phase is significantly higher than that of the pellet phase. This is completely different from the conventional packed bed where the phases have essentially the same temperature. A simplified model was developed to estimate this phenomenon in the packed bed with DBD under natural convection. The power consumption mechanism was investigated. The mechanisms for the electrical energy of inlet plasma transformed into heat energy in the two phases, gaseous and pellets of the packed bed reactor, are different. The energy transformation in the gaseous phase includes electron absorption as well as ion absorption. The energy absorbed by electrons, including ohmic heating and stochastic heating, maintains plasma condition. The energy absorbed by ions transfers to other heavy particles with frequent collisions in plasma sheath and, finally, raises the macro temperature of the gas. The energy consumption in pellet phase is dielectric polarization loss and depends on packed bed geometry and DBD. These mechanisms of energy consumption are introduced into the packed bed heat transfer model to develop the simplified model. Some experiments are performed and the results agree well with the numerical simulation of this model.