Throttling Process

Throttling Process Points : Throttling Process, thermodynamics cycles, Definition This type of expansion occurs when a gas or vapour is expanded through an orifice or aperture of minute dimension like a value which is very slightly opened or a narrow throat. Fluid under pressure is forced through that aperture but the velocity of fluid flowing out is reduced to a negligible amount by the high resistance offered by the friction between the fluid and the walls of aperture. Hence the kinetic energy of the fluid flowing out of aperture is very small. In fact the kinetic energy of the fluid has been converted into heat which warms up the fluid to an initial temperature. Thus no heat is supplied from or rejected to an external source and there is no external work done. Also there is no change in temperature in case of perfect gas. In the throttling process also, W = 0, Q = 0 and ?U = O.