Heat transfer to a surface reacting fluid in turbulent flow

Abstract

AbstractThe effect of chemical reaction on heat transfer has been studied for turbulent flow in tubes of a reacting gas. The analysis is carried out for a heterogeneous, catalytic reaction occurring at the wall surface. Equations are presented for predicting the increase in heat transfer coefficient due to reaction in terms of the rate of reaction, diffusion, and operating conditions. For an exothermic reaction the total heat transfer coefficient is increased when the gas temperature is greater than the wall temperature, and decreased when the gas temperature is less than the wall value. The effect is greatest for rapid reactions; that is, when diffusion of reactants to the tube wall determines the rate of reaction.The equations are applied to the catalytic hydrogenation of ethylene. The results show that the total heat transfer coefficient can be at least ten fold larger than the coefficient for a non‐reacting system at the same flow conditions.In general, the results of this study suggest that a wall‐catalyzed reaction can be an effective means of increasing the heat transfer rate from gases in turbulent flow in tubes. Furthermore, for a porous catalyst applied to the wall, enlarging the thickness of the catalyst layer will increase the effect on the heat transfer rate.