The calculation of heat transfer coefficient for combustion driven transverse oscillations in a gas-air burner



In this paper a method is presented for the computation of the heat transfer coefficient in a gas-air burner in the presence of combustion-driven transverse mode oscillations. By considering the oscillations in pressure within the chamber to be small compared with the mean chamber pressure, and to be known, methods of acoustics may be used to determine the average energy density of the acoustic waves at the wall. Consideration of this acoustic energy to create greater mixing in the boundary layer enables the heat transfer problem to be considered by the Dankwerts-Mickley model for turbulent heat exchange. With suitable definition of a friction velocity in terms of the friction velocity v* for fully developed turbulent pipe flow and the root mean square particle velocity of the acoustic wave (ar.m.s.ω), it is found that agreement exists between the computed ratio of heat transfer coefficients, with and without combustion-driven oscillations and the experiments of Zartman, which appear to be the only experimental data for transverse oscillations in a gas-air burner.