Numerical Simulation Analysis And Research Of The Cold Rice Seedling Greenhouse Environment Based On CFD

The northeastern region is located in a cold area,with a relatively cold climate and a large temperature difference between the morning and the night,in order to improve the quality of rice,growing rice has become an indispensable part in the cold regions of the north.The temperature and humidity inside the greenhouse are the important environmental factors that directly affect the growth of rice seedlings,therefore,it has great significance to ensure the uniform distribution of temperature and humidity in the greenhouse.Based on the rice seedling greenhouse as the research object,using CFD method to simulate the distribution and variation of temperature and humidity field and airflow field inside the greenhouse under the natural ventilation conditions,according to the actual growth requirements of rice seedlings optimize the ventilation structure of greenhouse,and the optimum ventilation configuration suitable for different lengths of rice seedling greenhouses in the northern cold regions was proposed.(1)Combining relevant theoretical knowledge of computational fluid dynamics,a mathematics model for the environment of rice greenhouses was established.Select standard k-? turbulence model,the wall function method is used for low Re-flow in near wall area,choose DO radiation model to solve radiation heat transfer,the rice seedling that planted in the greenhouse set as porous media model,using the component model to solve humidity inside the greenhouse.(2)Applying Gambit software to build a three-dimensional model which has an equal size of the experiment greenhouse,select the measured data as the simulation boundary conditions,using CFD method to simulate and research the environment of rice seedling greenhouse,the simulated temperature and humidity are compared with the measured values to verify the feasibility of the model.The results show that: the simulated values agree well with the measured values,through the simulation of CFD model can reflect the internal environment distribution of rice seedling greenhouse more accurately and accurately.(3)The verified CFD model was used to simulate and analyze the distribution and variation of temperature and humidity field and airflow field in the greenhouse under different conditions of wind speed and wind direction.(4)According to the actual rice seedlings in the period of growth demand,optimize the curtain height and the gate size of greenhouse,the optimized greenhouse temperature and humidity field and airflow field have obvious improvement effect,to meet the optimum growth environment of rice seedlings and the overall distribution is even,which has great significance to the growth and quality of rice seedling.(5)In order to ensure the growth of rice seedlings can have a good environment and improve the quality of the seedlings,through multiple numerical simulations and analysis,the optimum ventilation configuration for rice seedling greenhouse with different lengths in the northern cold regions is obtained,to provide theoretical basis and guiding significance in actual production and application.