Thermo Acoustic / Lamina Flow Stirling Hot Air Engine

The thermo-acoustic hot air engine also known as Lamina Flow Beta Stirling engine. This engine does have only one piston, two cold sides and one hot side.  Is a very simple devices for converting heat into motion. 


 


Historical

The history of thermoacoustic hot air engines start about 1887, where Lord Rayleigh discusses the possibility of pumping heat with sound. Little further research occurred until Rott's work in 1969. 


A very simple thermoacoustic hot air engine is the Rijke tube invented/discovered by Pieter Rijke, that converts some heat into acoustic energy. 


An older thermoacoustic hot air engine, where the speaker is replaced by a working piston, is the Lamina Flow engine or Lamina Flow Beta Stirling engine


 


Operation

The heat to be applied exactly where the mesh ends inside the tube. When the air inside the tube heats, it expands and cools down, then it heats again and the cycle repeats. At the beginning, the air is not hot enough so the oscillation is slow and weak. When the frequency of the oscillation is matched by the flyweel, it starts rotating. When more heat is applied, the frequency in the engine increases.