Numerical simulation on the two-phase flow pattern in the loop heat pipe with r-134a

Abstract

This paper discusses the two-phase flow pattern in the loop heat pipe with R-134a. A computational fluid dynamics (CFD) study was carried out using ANSYS FLUENT. VOF model was used to simulate interface between vapor and liquid phase of R- 134a. A UDF was used to model evaporation and condensation mass transfer between two phases. For the simulation of increase of pressure in the loop heat pipe, the ideal gas law was considered when modelling the density of vapor. The numerically calculated temperatures in this paper and Fadhl’s calculated temperatures and experimentally measured temperatures matched very well [2]. The maximum difference between the calculated and Fadhl’s temperature data is 2.4 %. The bubble figure in the loop heat was observed with time passed in this paper.