Analysis Of Two-Phase Flow And Heat Transfer Characteristics Of Heat Transfer Tubes With A Surge Tank

The heat transfer tube is the basic component for solving problems of heat exchange in the engineering application.While the dynamic change of the load and pressure of the system in which the heat transfer tube is located brings great potential dangers to the life of the heat transfer tube and the system safety.The surge tank can reduce the damage caused by the frequently change of load to the system,reduce system energy consumption and maintain the system pressure stability.Therefore,research on the transient parameters of two-phase flow in the heat transfer tube with a surge tank is of great significance to improve the safety of the heat exchange system.In this paper,the physical model is established based on the experimental paltform of H.T.Liu.The mathematical model is established based on dirft flux model.Then using MATLAB/Simulink simulation platform builds the simulation model.The accuracy of the model was verified by comparing the experimental data of H.T.Liu with the steady-state simulation data of the simulation model.The simulations under steady-state and dynamic conditions were carried out to investigate the flow and heat transfer regularity of heat transfer tubes.And the influence of a surge tank on the flow and heat transfer of the heat transfer tube was compared.In this paper,the total pressure drop data obtained under steady-state simulation and the experimental data under the heating conditions of 800 W,mass flow rate of 9.06 g / s and inlet fluid temperatures of-10?,0?,10?and 23? were compared,the maximum error is less than 5%,which verifies the accuracy of the model.Steady-state simulation was carried out under different electric heating power,different inlet fluid temperature and different mass flow conditions.The variation regularity of each flow parameter is obtained.In the study of the dynamic flow heat transfer regularity of heat transfer tubes,it was found that the system is more stable when the heat flux is lower.Comparing the simulation data of the tube with a surge tank and a tube without a surge tank,when the mass flow step changes,the response time of the pressure drop of the tube with a surge tank is reduced by 5.3 s and the amplitude is reduced by 0.95 kPa.The response time of the void fraction and the quality of gas also decreased by 14 s and 12.5s respectively.Observingthe data of the mass flow and inlet fluid temperature step changed,found that boss the response time and amplitude of the two-phase flow parameters of the tube with a surge tank is smaller.To sum up,the simulation model successfully simulates the change of transient parameters of two-phase flow in heat transfer tube with a surge tank,which has great significance to improve the safety of heat transfer tube.