Mechanocaloric Effect

an effect observed in liquid helium below the temperature of the transition into the super-fluid state (below 2.19°K): when helium flows out of a vessel through a narrow (approximately 1 μ) capillary or orifice, the helium remaining in the vessel is heated. This effect was discovered in 1939 by the British physicists J. G. Daunt and K. Mendelssohn; the effect was explained by the quantum theory of superfluidity. The inverse effect—the flow of helium induced by the introduction of heat—is called the thermomechanical effect.