Papers by Author: Song Bo Zhang

Abstract: In this paper, the three straight casing tubes and the double helix casing tubes were modeled using the Gambit software. And the fluid flowing in tubes was simulated by Fluent software. According to the simulation results, with the field synergy principle, two casing tubes’ flow and temperature distribution of carbon dioxide and water have been analyzed. Simulation data show that the double helix casing tubes is better than the three straight casing tubes on heat transfer and synergy. Lay the good foundation for design optimization and efficiency of heat exchanger of carbon dioxide heat pump system.

Abstract: In the design of a carbon dioxide heat pump water heater evaporator, the effect of the circuit number on the evaporator is investigated numerically by EVAP-COND 3.0 version simulation package of American National Institute of Standards and Technology. It is found that as the circuit number increases the temperature difference between the air and the refrigerant increases, but it reduces the overall heat transfer coefficient. The evaporator capacity will rise firstly, and then drop with the circuit number and achieve the maximum in the optimum circuit number. Therefore, selecting the appropriate circuit number of the evaporator can significantly improve the efficiency and optimize the design.

Abstract: By using the FLUENT software, the flow and heat transfer properties of several elliptical tubes were numerically studied. The mathematical models of the tubes flow field were established. The implementation incorporated a SMPLE-based semi-implicit solution algorithm that was applied to iterating calculation. Results shows that the surface heat transfer coefficient, temperature difference between inlet and outlet were all higher than circular tube, when mass flux equal to at inlet of elliptical tubes and circular tube and wall temperature was invariable. Therefore, the elliptical tube is a kind of effective heat transfer enhancement element.