16. Thermoacoustic Engine 热声发动机

A piston placed in the open end of a horizontal test tube which has its other end partially filled with steel wool may oscillate when the closed end is heated up. Investigate the phe­no­menon and determine the efficiency of this engine.

一根水平放置的试管，开口端有一活塞，封闭端塞入钢丝绒。当试管封闭端被加热时，活塞可能会振动。研究该现象并确定该发动机的效率。