Flow Field Analysis And Optimization Design Of Air Source Heat Pump Chrysanthemum Drying Chamber

The uniformity of flow field distribution in chrysanthemum drying room is the key factor affecting the overall drying quality of chrysanthemum.This paper takes an air source heat pump chrysanthemum dryer produced by a company as the research object,establishes a numerical simulation scheme of the flow field in the drying room,deeply studies the influence of tray spacing,deflector Angle and wind speed of hot air inlet on the flow field distribution in the drying room,and provides a theoretical basis for the optimal design of the chrysanthemum drying room.The main research contents of this paper are as follows:According to the drying principle of chrysanthemum and the characteristics of moisture transfer in the three drying stages of chrysanthemum,the flow field distribution in the drying chamber in the constant rate drying stage was determined as the main numerical simulation object.The porosity,viscous resistance coefficient and inertia resistance coefficient of chrysanthemum layer were calculated according to the experimental results of chrysanthemum physical property parameters.The evaluation indexes and influencing factors of chrysanthemum drying quality were given.By use of CFD numerical simulation software of drying chamber flow field numerical model is set up,according to the simulation results of drying room to study the distribution of velocity field and temperature field,get the drying chamber,high temperature,hot air near the entrance to the wind speed in vertical direction hot air flow is blocked,the wind speed dead center area is big,drying room overall speed and temperature distribution uniformity is poor;The experimental results show that the error between the simulated results and the measured results is less than 8%,which verifies the reliability of the model.On the basis of expanding 200mm in front and back of chrysanthemum tray and changing the direction of hot air outlet,three single factor values of tray spacing,deflector Angle and hot air inlet wind speed were changed respectively to analyze the distribution law of temperature field and velocity field of drying chamber under each parameter.The results showed that the smaller the distance between chrysanthemum trays,the larger the wind speed within the distance,and the better the uniformity of wind speed between different layers.The greater the Angle between the inlet guide plate and the horizontal direction,the better the uniformity of the velocity field distribution in the drying chamber.The higher the inlet wind speed is,the better the uniformity of the velocity and temperature distribution between the trays in the drying chamber is.The optimal parameters of the three single factors were comprehensively analyzed by orthogonal test method.The distribution uniformity of the flow field velocity and temperature cloud map in drying chamber,the distribution curve of the flow field,the non-uniformity coefficient and the average value were used to comprehensively evaluate the distribution of the velocity field and temperature field of 9 groups of parameters.Group 7 A3B1C3 is determined to be the final optimization scheme,that is,on the basis of expanding 200mm in the front and back positions of the tray and changing the direction of hot air outlet,the tray spacing is set to 40mm,the Angle of upper and lower diversion plates is 45°,and the wind speed of hot air inlet is 3.5m/s.Figure[38]Table[11]Reference[61]...