CFD-BASED SIMULATION AND MODEL VERIFICATION OF PEACHES FORCED AIR COOLING ON DIFFERENT AIR SUPPLY TEMPERATURES

Abstract

To ensure optimum peach quality during precooling, air supply temperature within the precooled facility should be precisely controlled. Three-dimensional unsteady computational fluid dynamics (CFD) model was established in this research, taking air supply temperature as an influencing factor, a dynamic simulation of this model was performed based on Fluent, and its reliability was verified through experiments. Simulation results showed that the decrease of air supply temperature did not affect the 7/8ths cooling time (SECT) significantly, but shortened the cooling time of the fruit which was cooled from the initial temperature to a fixed temperature, especially when air supply temperature dropped below 4oC, its corresponding cooling time showed a trend of steady variation. Meanwhile, respiration rate of 6-8 oC was about twice as high as that of 2-4 oC, its corresponding moisture loss was also increased by 34.71-39.74%. Thus, the range of 2-4 oC was more suitable for quick precooling peaches after harvest. Experiments showed that the root mean square error (RMSE) of 0.7 and 2.7 m·s-1 were 0.747 and 0.836 oC, respectively. It could be seen that simulation results were in good agreement with experimental results, which fully verified the feasibility and high accuracy of this new modeling method. Finally, this study can provide a reliable reference for establishing an accurate precooling numerical model, and rationally optimizing air supply temperature range of fruits precooling experiment to maintain its high quality.