Numerical Simulation For Heat Transfer And Flow In Porous Solar-wall

Solar-wall is a novel solar heating technology which has proven to be effective both in heating and ventilation. It consists of a heat collector system which includes a porous wall and a passage between the porous wall and the existing wall and an air distribution system which adopts under floor air distribution in this thesis.The principle, characteristic and examples of solar-wall are introduced at first. Then, the heat collector system and under floor air distribution system are numerically studied. The non-equilibrium porous media model has been used to describe the porous wall and buoyancy-driven flows in the passage and apartment are taken into account.The flow fields and heat transfer characteristics in the heat collector system are numerically simulated. The effect of inlet velocity distribution on the performance of collector system and the effect of permeability and width of passage on inlet velocity distribution are analyzed. Then the effect of pressure difference between inlet and outlet, efficient conductivity of matrix and heat coefficient between flow and matrix on the temperature distribution in the porous wall is analyzed. At last, the effect of these parameters on the mean air temperature of outlet, mass flow rate, heat absorption of air is analyzed. Also, the heat transfer enhancement of heat collector system is studied according to field synergy principle. The outcome indicates appropriate permeability and widths, improving efficient conductivity and heat coefficient may improve the performance of heat collector system.The flow fields and heat transfer characteristics in the under floor air distribution system are numerically simulated. The temperature and velocity distribution are available by finite volume method. The effect of sizes of floor diffuser, inlet air parameter and design of under floor on the air flow distribution is analyzed. The outcome indicates increasing the height of raised floor, adopting slope floor design and non-uniform floor diffuser may improve the equality of air flow in every floor diffuser. Through the simulation and analysis of the heat collector system and under floor air distribution system, the flow fields and heat transfer characteristics of solar-wall are more intuitionistic and reference is provided to the parameter selection.