Nonlinear effect in a thermoacoustic refrigerator

Thermoacoustic refrigerators based on thermoacoustic effect generally work with high amplitude sound waves, which could go with intense nonlinearities. In present work, an experimental apparatus of thermoacoustic refrigeration was built up to investigate the effect of stacks on nonlinearities and the effect of nonlinearities on the performance of thermoacoustic refrigerator. Experimental results indicate that while with stacks in the resonator, acoustic wave amplitudes are weakened, pressure ratios are cut down by 5%, high harmonic amplitudes and growth rates are decreased compared with the case of no stacks; nonlinear effect stabilizes the sound wave and causes the production of high harmonics, moreover, both the growth rates of sound wave and high harmonics are tend to be flat; the thermoacoustic effect is obvious while with stacks in the resonator, and no-load temperatures are increased first and decreased then as the acoustic powers are increased, which reach the lowest value 5.1°C while the acoustic power is 50 W.