The stack was made of stainless steel wire mesh screens with mesh

A research on the influence of resonator length on the performance of a standing wave thermoacoustic prime mover has been conducted. The thermoacoustic prime mover consists of an electric heater, a resonator tube filled with atmospheric air, and a stack. The stack was made of stainless steel wire mesh screens with mesh number of #14.
The stack had a length of 561cm and placed 1361cm from resonator hot-end. The resonator tube was made of stainless steel pipe with 6.861cm inner diameter. The electric heater which has a maximum power capability of 29961W was attached to the hot side of the stack.
We varied the resonator length from 10561cm until 20561cm. It was found that the thermoacoustic prime mover with a resonator length of 15561cm generated the sound with the smallest onset temperature difference and shortest time to reach the onset condition, those are 252 °C and 401 s, respectively. Also, the prime mover with a resonator length of 10561cm produced the highest frequency that is 17461Hz. On the other hand, by using resonator length of 18061cm, the prime mover generated the highest pressure amplitude of 0.004161MPa, and the thermoacoustic device delivered the highest acoustic power of 2.861W and efficiency of 0.9%.