Numerical Simulation Of The Condensation Heat Transfer Characteristics In The Two-Phase Closed Thermosyphon

The heat pipe has been widely used since its appearance because of high thermal conductance and other excellences, so the theoretical analysis and experimental investigation of the heat pipe is becoming more and deeper. Founding mathematic models is one of the important methods, which can penetrate with the core of the heat transfer mechanism. Also it can provide dependable forecast under different operate conditions as well as theoretical guidance for experimental studies.After a simple retrospect of the development and application of the heat pipe, the working elements and the history and the actual state of the investigation inside the thermosyphon, a numerical model based on the previous experimental and theoretical studies is developed to simulate and analyze the process of the flowage and heat transfer in the condensator of the two-phase closed thermosyphon. The model is based on the Nusselt's solutions by considering the factors of vapor-liquid interfacial shear stress, the super-cold and the density of the vapor which have important influence on the heat transfer performance of the thermosyphon.This model is used to analyze how the parameter such as the pressure of the saturated steam, the heat input of the thermosyphon and the geometrical measurement affect the distribution of the temperature and the velocity in the liquid film, the width of the liquid film, the vapor-liquid interfacial shear stress. These influences as well as the actions between the internal factors then affect the heat transfer characteristics in the thermosyphon. The method of dispersing the width of the liquid film is used in the calculation to obtain the numerical value of the condensation heat transfer coefficient. The numerical simulation discrete value has the same trend with the Nusselt theoretical value. So this model can simulate the working status of the condenser section of the thermosyphon.Such analysis elucidates the principle of how the external conditions and the internal factors affect the condensation heat transfer characteristics in the thermosyphon, increases the understanding of the working process of the condenser of the thermosyphon, also has an active action to the theoretical analysis and the actual application. So the work can instruct the design of the thermosyphon and heat pipe exchanger and the correlative equipments.