Heat transfer in turbulent gas flows at high-frequency pressure oscillations

The effect of pressure fluctuation on the heat exchange in the turbulent gas flows has been studied. The physical model of the process describes behaviour of the viscous layer adjacent to the surface. The criterional equation for the heat transfer relative coefficient is derived as a functional dependence on one similarity criterion, i.e. on the relative thickness of the viscous layer. Results are given of the experimental research of the heat transfer maximum coefficient (Ksub(max)) at resonant fluctuations of the air in the channels, dia. 12.2 and 30 mm, 1.1-3 m in length. The basic parameters have been changed within the following ranges: pressure of 1-20 bars, temperature of 100 to 600 deg C, Re=104-2x105, frequency of 90 to 1000 Hz. It is shown that Ksub(max) is proportional to the relative thickness of the viscous layer