The flow field and temperature field around the isothermal sphere in a uniform flow with acoustic waves have been studied numerically and using its results, the stability limit of the Rijke Tube with spherical heat sources has been investigated.
The temperature change of gas causes a volumetric change, and it may convert thermal energy to acoustic energy under certain condition which have been clarified very rarely.
Using the calculated heat transfer response of an isothermal sphere to the particle velocity of an acoustic wave, the amount of converted energy in a cycle has been computed by introducing the efficiency factor E.
By equating the acoustic power generation from the heater to the power dissipation in the tube, the onset condition for the thermoacoustic oscillation has been obtained.
And it has been found that the stability limit of the Rijke Tube with spherical heat sources is very similar to that of the Rijke Tube with cylindrical heat sources.
