Unsteady convective heat transfer for turbulent flows of gases and liquids in tubes

Abstract

The paper presents an analysis and generalization of experimental data on the unsteady heat transfer of gases and liquids flowing in tubes under the conditions of heating/cooling and variation in the flow rate, heat release in the tube walls, and entrance flow temperature. The comparison between the results of theoretical analysis and experiments has made it possible to find the distribution of turbulent flow parameters over the tube radius and to determine the effect of variable flow structure on heat transfer. Different findings concerning the non-stationarity effects on turbulent flow characteristics are compared with the data of experiments. As a result, the correlations have been derived to calculate the unsteady heat transfer coefficient. Engineering calculation methods for real unsteady thermal processes are suggested.