荔枝差压预冷的数值模拟与实验研究

Simulation and Experimental Study of Litchi’s Forced-air Pre-cooling

目前针对小果径果蔬的差压预冷压降规律尚不明确,风机选型无依据,导致预冷“不透”问题时常存在。本文采用fluent软件数值模拟与实验验证的方式,以荔枝为研究对象,研究不同送风速度下荔枝的降温与通风阻力特性,模拟与实验的相对偏差总体小于15%,结果表明荔枝最佳预冷风速在1.5 m/s左右,预冷阻力特性符合Ramsin基本方程,通过实验数据拟合确定了压降与速度的关系式(ΔP=18.49v^(1.97));通过仿真压力随填装长度的变化拟合获得了压力与填装长度(沿风向)的关系式(P=0.211L-9.335),为差压预冷通风阻力特性的研究提供参考依据。

At present,pre-cold pressure drop law is not clear for small diameter fruit and vegetable,and fan selection without basis lead to problem of pre-cooling"airless".In this paper,the numerical simulation and experimental verification of fluent software were used to study the cooling and ventilation resistance characteristics of litchi as the research object.The relative deviation between the simulation and the experiment was less than 15%overall.The results showed that the optimum pre-cold wind speed of litchi was about 1.5 m/s,and the pre-cooling resistance characteristics conformed to Ramsin’s basic equation,and the relational formula was ΔP=18.49v^(1.97) between pressure drop and velocity was determined by the fitting of experimental data.The relational formula was P=0.211L-9.335 between pressure and filling length(along the wind direction)was obtained by simulating the pressure with the change of filling length.It provided a reference for the study of the resistance characteristics of differential pressure pre-cooling ventilation.