The Best Explanation of How a Thermoacoustic Engine Works
Lord Rayleigh discussed the possibility of this kind of engine back in 1887 but was unable to make it a reality due to technological limitation at the time.
The engine is demonstrated in the video by a small model engine that has an optimum running speed is 2700 rpm when warmed up fully.
The video’s host suggests that it is the fastest thermoacoustic engine available.
“The thermoacoustic engine works by converting sound waves into motion. The sound waves are generated by heating one end of a 'stack' of coiled material and allowing the other end to remain cool," says the video's description.
This particular engine is fired by a small spirit burner but the fuel could be anything stable. When the end of the coiled 'stack' is heated a bouncing pressure wave is set up inside the tube.
The pressure fluctuations inside the tube drive the engine. In the expansion phase, the piston is pushed outwards, in the contraction phase the piston is pulled inwards.
This type of engine requires a push start for the flywheel, or else the pressure and velocity of the standing wave remain at equilibrium.
Via: Grand Illusions