Numerical Simulation And Signal Analysis Of Solar Greenhouse Ventilation Process

In the cold arid regions of northern China,the "three verticals and one slope" solar greenhouse is widely used in the winter agricultural production,the temperature and humidity of the inner environment of solar greenhouse show the function relation with time.The temperature and humidity data of the air soil in a vertical section of the greenhouse were collected by means of dense distribution points in the experiment,and the steady state simulation of the experimental data is carried out by means of computational fluid dynamics.The sensor collects data at intervals of 30 minutes,showing the characteristics of discrete time signals.By analyzing the temperature and humidity data of sunny days and dividing the temperature and humidity data within 10 days,the following conclusions are obtained from the dual hypothesis testing of temperature and humidity data in the ventilation process:(1)The solar greenhouse containing the inner arch can effectively reduce the air humidity in the greenhouse after opening the vent,and the temperature of the canopy area remains within the optimum range of crop growth.(2)The heat from the greenhouse in sunny days comes from outside sunlight,while the snow day is due to radiation from the internal soil and clay walls.(3)The simulation results show that the middle position of the lower area of the arch canopy and the span of the crop canopy is higher than that of other regions,note that there is water accumulation in this area.And the humidity in the solar greenhouse in the snow day is evenly distributed.There is no significant difference in height or span.(4)When the cycle is divided by the time nodes of ventilation,the fitting degree of fitting function is higher,while there are fewer phases.(5)When the false alarm probability PF=0.0099,the inspection system has high detection rate.This means that signal processing can be used to process data in solar greenhouse studies.(6)The delay time detection of temperature and humidity in ventilation process indicates that at the sampling level of30min/ time,it is impossible to detect the sequence of temperature and humidity affect the environment in the solar greenhouse.If the sampling interval is small enough,the corresponding results can be detected.