Local composition shift of mixed working fluid in gas–liquid flow with phase transition

Local composition shift is an important characteristic of gas-liquid mixture flow with phase transition. It affects the heat transfer process, stream sonic velocity and the mixture distribution in the thermodynamic cycle. Presently, it is mainly calculated through the empirical models of the void fraction from pure fluid experiments. In this paper, we made efforts to obtain it and its rules basing on conservation equations derivation. The result calculated with propane/i-butane binary mixture was verified by the experiment in the evaporator of a refrigerator. As an extending, it was applied to a ternary mixture with components of methane, propane and butane and more information was presented and analyzed. The calculation approach presented in this paper can be applied any multicomponent mixture, and the rules will be helpful to improve the composition shift theory.

► Local composition shift of mixed working fluid in gas–liquid flow was modelled.
► A solution method for local composition of gas–liquid flow was proposed.
► The solution method was verified by the experimental result.
► Local composition shift mechanism of gas–liquid flow was studied