Numerical study on the two-phase flow pattern and temperature distribution in a loop thermosyphon as a defrost device at the evaporator in the refrigerator

摘要

This paper discusses the two-phase flow pattern and temperature distribution in a loop thermosyphon as a defrost device at the surface of the evaporator in the refrigerator with different heater locations and different heating power. A computational fluid dynamics (CFD) study was carried out using ANSYS FLUENT 15.0. The volume of fluid (VOF) model was considered to simulate evaporation and condensation at the heater surface using user-defined functions (UDFs). 2D geometries were developed with a heater inserted in the loop thermosyphon. The simulation results were verified using Fadhl's experimental and numerical temperature data [2]. The maximum difference is 2.4 % between the calculated data and Fadhl's data. The two-phase flow pattern and the temperature field varied with the different heater locations and heating power values. The thermal performance was evaluated based on the average temperature and temperature uniformity inside the loop thermosyphon.