THE MARGINAL CONDITION FOR THE ONSET OF THERMOACOUSTIC OSCILLATIONS OF A GAS IN A TUBE HAVING A WET WALL POROUS MEDIUM

摘要

Propagation of an acoustic wave in a tube causes the oscillations of pressure, temperature, and specific volume of a gas. When these oscillations are coupled with the thermal interaction between the gas and the wall of the tube, a rich variety of thermoacoustic phenomena is produced. As one of the thermoacoustic phenomena, a self-sustained gas oscillation is known: when a porous medium located in a tube is differentially heated, a gas in the tube can spontaneously oscillate. In this study, we numerically investigated the marginal condition for the onset of the self-sustained gas oscillation by using the theory proposed by Raspet et al.[JASA Vo. 112, 1414 (2002)]. This theory can treat the effect of condensation and evaporation of working gas. The numerical result was compared with the experimental result and a good agreement between them was obtained.