The thermagoustic irreversibility for a single-plate thermoacoustic system

The problem of thermagoustic (thermo-magneto-acoustic) irreversibility near a single-plate, representative of the stack in a thermoacoustic engine, is modeled and analyzed in this paper. Assumptions (long wave, short stack, small amplitude oscillation, boundary layer type flow, etc.) are made to enable simplification of the governing continuity, momentum, and energy equations to achieve analytical solutions for velocity, temperature, and pressure. A general equation for entropy generation is derived from first principles that accounts for the transverse magnetic force present in a magnetohydrodynamic system. This entropy generation equation is then simplified in order to model the specific thermoacoustic situation considered in this paper. Finally, a time-averaged entropy generation rate followed by a global entropy generation rate are calculated and graphically presented for further analysis.