Procedures to Predict the Change of Thermodynamic States in Ducts with Friction and Heat Transfer

Abstract

The principle to predict the change of thermodynamic states of fluid flowing in a channel with fluid friction and heat transfer is established. Then it is applied to analyze the flow of supercritical helium in a very long conduit. The assumption in the process of formulation includes steady one-dimensional flow without the influence of body force, uniform cross section and uniform heat flux at the wall, and known prescribed friction coefficient which depends only on the Reynolds number. The effect of the Joule-Thomson coefficient which is an important factor for the thermodynamic analysis of cryogen in supercritical state and the influence of the term of kinetic energy which is often neglected in the engineering analysis of the flow system are examined. It is clarified that their contributions are of definite importance for long channels.