Loop Heat Pipe: Simple Thermodynamic

Abstract

The LHP is a two-phase device with extremely high effective thermal conductivity that utilizes the thermodynamic pressure difference to circulate a cooling fluid. A thermodynamics analytical model is developed to explore different parameters effects on a Loop Heat Pipe (LHP).. The effects of pipe length, pipe diameter, condenser temperature, and heat load are reported. As pipe length increases and/or pipe diameter decreases, a higher temperature is expected in the evaporator. Keywords—Loop Heat Pipe, LHP, Passive Cooling, Capillary Force. NOMENCLATURES A wick cross sectional area, m p C specific heat capacity of the liquid, kJ/kg.K CPL Capillary pumped loop CPS Coherent Porous Silicon h enthalpy, KJ/kg cc h convection coefficient in the compensation chamber, W/mK k thermal conductivity, W/m.K pipe length, m L wick thickness, m LHP loop heat pipe M mass, kg m mass flow rate, kg/s P pressure, Pa Q heat flow, W R pipe radius, m T temperature, K V volume, m x quality Greek symbols ρ density, kg/m μ dynamic viscosity, kg/s.m e porosity (0 to 1) σ surface tension, N/m β volumetric ratio (0