Mathematical modeling of multiple evaporators/condensers loop heat pipe operation with flow regulator under various operating conditions

Abstract

In this study, mathematical models of multiple evaporators and condensers loop heat pipes (MLHP) were established, and several tests were conducted to identify the operating characteristics of MLHP. Flow regulators that can regulate the mass flow rate in each condenser according to each condenser's temperature were designed and applied. Pure acetone was chosen as the working fluid, and the temperature was measured by T-type thermocouples under different test conditions. Three types of tests were conducted in this study, and the corresponding mathematical models were established. When two evaporators were heated, the model reproduced the experimental data well, with the exception of the temperature of the vapor line; this difference was attributed to the effect of non-condensable gas. When one evaporator was heated, the model accurately reproduced the experimental data. Both test and calculation were performed for MLHPs operated with and without a flow regulator. When a flow regulator was employed, the compensation chamber temperature and the confluence of the liquid line were lower when MLHP was operated without a flow regulator, confirming the efficiency of the flow regulator. The ratio of mass flow rates on each side was also evaluated using the mathematical model.

Keywords

• flow regulator
• loop heat pipe
• multiple evaporators and condensers
• two-phase heat transfer
• mathematical model of steady state