Research Of Theoreticalanalysis And Simulation On Airflow Distribution Of Heat Pump Mushrooms Drying Room

In recent years, with the rapid growth of mushrooms market demand, heat pump drying technology has become a hot research of many scholars domestically and globally.However, there exists issues including poor product quality, temperature and humidity fluctuations and serious energy waste among existing heat pump drying techniques,leading to the heat pump drying room cannot meet the technical requirements, also includes low operating efficiency and difficult promotion. Based on the pros and cons and key technology of heat pump mushroom drying room, the conclusion whether airflow distribution of drying room is reasonable or not directly affect the quality of dried mushrooms and energy consumption level throughout the drying process of heat pump units is draw, and so this paper mainly involves theoretical analysis and simulation of airflow in heat pump drying mushrooms room. Setting the heat pump mushrooms drying room of Xixia County in Nanyang City as prototype, we established numerical model, set the boundary conditions, meshing and simulation with professional HVAC simulation software Phoenics. For the entire drying period, the air distribution in vertical height direction of each module in mushrooms drying room were simulated and analyzed, the results showed that: the air distribution in vertical cross-sectional layer of mushrooms is getting air uniform with mushrooms pile height drop during the drying process. With simulation analysis, the impact of grid spacing arrangement on indoor wind speed and total average speed uniformity coefficient was found while the grid spacing of 10 cm in drying room air distribution can achieve the best results, the overall speed irregularitycoefficient of material room minimized. In order to improve the energy efficiency of ventilation system, according to the rated air volume(2.5~5m3/s) and analysis of the return air volume, hot air circulating utilization efficiency under different conditions of each drying period, we found the most economical and reasonable air volume: the preliminary drying stage shall maintain a larger air volume, the constant drying stage can maintain a larger air volume also, the amount of air volume in drying stage should be kept within 3~4m3/s range, and in the mushroom shaped stage heat pump should be kept small amount of air volume. Achievement of this study provide a great reference value for the development of new heat pump drying technology, has an important guiding significance to promote the modernization of mushroom industry.