Study on Minor Losses Around the Thermoacoustic Parallel Stack in the Oscillatory Flow Conditions

Minor losses around the thermoacoustic parallel stack in the oscillatory flow conditions are amongthe main factors that influencethe efficiency ofthermoacoustic systems. In this paper, a two-dimension model of a thermoacoustic parallel stack in a thermoacoustic system driven by double loudspeakers is setup. The characteristicsof the vortex structure at the end of the parallel stack under different pressure amplitude are analyzed. Meanwhile based on the principle of the two-microphone method and the above simulation result, the minor loss coefficient of oscillatory flow through a sudden area change is analyzed. The result shows that the vortex structuresget larger with the increase of pressure amplitude. Furthermore, the real part of the minor loss coefficient exponentially increases with the ratio of hydraulic radius and displacement amplitude of the oscillatory flow. A close agreement between simulation and experimental result is found, thus providing support for the validly of the model.