New Technologies of Pressure Pre-Cooling Flow Field Uniformity

Abstract

Flow field uniformity in the process of pressure pre-cooling can ensure fruit and vegetable pre-cooling effect. Flow field of pre-cooling packing boxes under 5 different opening modes were calculated through numerical simulation, including velocity distribution, temperature distribution and pressure distribution. The simulation results were also verified by experiment. Both theoretical and experimental results showed that the greater the external covering opening ratio, the faster the cooling. Temperature of the measure points away from the pressure fan side with a small opening ratio reduced more rapidly than that with a big external opening ratio. The opening ratio of the external covering should be lower close to pressure fan side than that away from it. Therefore in actual pre-cooling work, the opening ratio close to pressure fan side should be lower than that away from it. The diameter of the openings distributed at the lower part should be smaller than that of the openings distributed at the upper part of the external covering and this can overcome pre-cooling non-uniformity between upper and lower layers.