农产品空气能热泵烘房温度场的数值模拟与验证

农产品热泵烘房温度场均匀性是影响农产品干燥品质的重要因素。本文选用5HGR-35型农产品热泵烘房,通过交互式CAD/CAM系统(UG)软件建立热泵烘房3D模型,运用理论分析与计算流体动力学(Computational fluid dynamics,CFD)模拟相结合的方法,研究其内部温度场分布情况,对现有结构烘房的温度场建模模拟,分析模拟结果并对现有结构进行优化。通过模拟得出结论:送风速度越大,烘房内热空气更新越快,换热效果越好。综合温度场分布以及农产品烘干要求,烘房内合理的送风速度为11 m/s左右;在11 m/s风速下,烘房空载时在15 min左右达到设定温度(65℃);小推车设计高度加大300~310 mm烘房内部温度场更均匀;烘房顶部均匀加入3块长×宽×高=2900 mm×20 mm×300 mm的挡板,可以使烘房内部温度场更均匀;小推车与烘房之间及相互之间保持30 mm左右间隙摆放更有利于烘房内部温度场的分布;验证试验中,模拟温度与实测温度吻合性良好。上述结论对烘房的进一步优化设计具有一定的指导意义。

Numerical Simulation and Verification on Temperature Field in Air Energy Heat Pump Drying Room for Agricultural Products

The temperature uniformity in the air energy pump drying room is an important factor affecting the drying quality of agricultural products. This paper chooses 5 HGR-35 type air heat pump drying room, establishes a3 D model for the drying room by interactive CAD/CAM system(UG) software, researches the distribution of temperature field in the drying room using theoretical analysis combined with computer simulations(CFD) method, modelings and simulates the temperature field of the existing structural drying room, and analyzes the simulation results and optimizes the existing structure. Conclusion: the greater the air supply velocity is, the faster the hot air in drying room renews is, the better the heat transfer effect is. Comprehensively considering the temperature distribution and drying requirements of agricultural products, the reasonable air supply velocity in drying room is around 11 m/s,the setting temperature(65 ℃) can be reached in about 15 min at no load condition. When the small carts design height is increased by 300~310 mm, when 3 baffles with 2 900 mm×20 mm×300 mm(length×width×height) are installed evenly at the top of the drying room, and when the gaps between the carts, and the wall and the cart are 30 mm,the internal temperature field of drying room can be more evenly. Verification test shows that the simulated temperature coincides well with the measured temperature. Which has practical guiding significance for the further optimization design of drying room.