Numerical Analysis Of Venlo-Type Greenhouse In Summer Thermal And Humid Environment

With the fast development of the computer technology, the computing power of CFD (Computational Fluid Dynamics) software, like Fluent, has got great improvement, which results in revolutionary advancement in the design study. The field of vision of greenhouse structural designing was broadened by applying CFD method in the greenhouse researches, showing CFD's great potential in scientific and practical application.This dissertation took the Venlo-Type glasshouse in the campus of Zhejiang University of Technology as the research object, analyzed the greenhouse thermal and humid environment at the super heat condition in summer, and verified the temperature and humidity factors affecting greenhouse thermal environment, upon which based the reasonable simplification for the CFD model. Then definition of the computation domain, the form of the flow field governing equations, and the choice of rapids model, radiation model and gas-liquid two-phase model as well were proposed for CFD simulation.Experiments in the greenhouse at the super heat condition in summer were performed to collect data about temperature and relative humidity distribution inside the greenhouse both in vertical and horizontal directions, and weather data outside as well, providing data resources for the set of parameters in the CFD model.Considering the heat and moisture transfer analysis between water droplets and heat air in the wet-curtain, the first time using the gas-liquid two-phase model theory in greenhouse numerical simulation, Data analysis was carried out to complete the definition of the boundary conditions and the establishment of the CFD validation model. The greenhouse thermal and humid environment under was simulated employing the CFD model constructed before. The numerical results got good agreement with the experiment data at the super heat condition, which confirmed the accuracy of the definition of the boundary conditions and the validity of the CFD model. Then used simulation results and adopted empirical formula in air-conditioning theory about temperature and relative humidity, analyzed the relationship between temperature and relative humidity at the super heat condition.On the basis of the above research, the CFD method was used to simulate the cooling and humidifying effect under different greenhouse structure configurations like the arrangement of different height of wet-curtain and fan and different parameters of structure size of wet-curtain and its flow parameters, and optimized their respective programs for cooling and humidifying. Then made use of large scale system theory obtaining the best program in cooling and humidifying for Venlo-Type greenhouse at the super heat condition in theory.