Numerical Simulation of Characteristics of Cross-Flow Heat Transfer in Pulsating Flow

Abstract

In order to investigate the characteristics of heat transfer in oscillating flow, the computational fluid dynamics method was employed to study the effects of pulsating flow on the heat transfer process in a cross-flow heat exchange pipe, and to analyze the underling mechanism which controls the improvement of heat transfer in pulsating flow through the distribution of temperature. Several pulsating frequencies (f=0, 5, 10, 50, 100, 150 Hz) and a wide range of pulsating amplitudes (inlet velocity u=2.0+Asin(2πft) m/s, A=0, 2, 5, 10, 15, 20 m/s) were explored to find out the best pulsating parameters for heat transfer. Results showed that pulsating flow with a low pulsating frequency (the magnitude of ~101 Hz) should be selected to obtain large heat transfer coefficient, and that pulsating flow with larger pulsating amplitude results in greater heat transfer coefficient. On the other hand, results revealed that only a limited length of the cross-flow exchange pipe was affected by the pulsating flow compared to the whole length, and that the affected length is longer with lower pulsating frequency and larger pulsating amplitude.