Mathematical modeling and numerical study of the heat transfer process in a heat pipe

A mathematical model has been developed and a numerical study has been conducted to determine the change in the amount of heat in a solar dryer heat pipe along its length, taking into account its geometric dimensions, outside air temperature, and solar radiation intensity. In the proposed model, the heat pipe under study is made of copper, and water is used as the working fluid. The length of the heat pipe is 0.2 m, the inner diameter is 0.045 m, and the wall thickness is 1 mm. The wick thickness is 1 mm, the porosity is 0.9, the wick conductivity is 0.0015 m2, and the effective pore radius is 54 mm. The full rate is 4.4%. The length of the evaporator and condenser is 0.05 m each. The amount of heat transferred and removed is 200 W. The operating temperature and heat flux to the heat pipe operating in steady state directly affect the steam velocity. Using the proposed model, the effect of the operating temperature on the steam dynamics was studied for four cases. The operating temperatures for these four cases are 50, 75, 100 and 120 ℃. The same amount of heat is transferred in all cases. The results of modeling the change in steam velocity along the length of the pipe are presented.