| Since 1980 s,the frozen food industry has been developed rapidly in our country.When food is cooled through the cooling tunnel,the speed and volume of the air influences the cooling effects heavily.Unreasonable settings of processing parameters will lead to drying sublimation of the moisture,epidermal rapture and other defects on the surface of the frozen food.In addition,the stucture of the cooling tunnel affects the uniformity of the flow field.An reasonable stucture of the cooling tunnel can decrease temperature difference between inner and outer sides of the conveyor belt,improve cooling efficiency and reduce energy consumption.The numerical simulation of cooling tunnel can predict the cooling effect of food,optimize the air speed,air volume and other technical conditions,fan position,baffle size and other tunnel structure,these actions can save operating costs and improve the quality of frozen products for enterprises.In this paper,FLUENT software is used to simulate the cooling tunnel of a quick-freezing device,and the variation law of the velocity field and temperature field in the cooling tunnel with the air supply velocity is analyzed,and the optimum air supply speed is determined according to the minimum and uniform temperature difference.Under this condition,the baffle is added and the effect of the cooling tunnel structure on the cooling efficiency is simulated.Through the study of this paper the following conclusions are found:(1)When the air speed is increased from 12m/s to 13m/s and 14m/s,the velocity range in the low velocity field is reduced and the uniformity of the velocity field is improved.When the speed is increased to 15m/s,the distribution of velocity field does not change significantly.(2)When the air blowing speed is increased from 12m/s to 13m/s,14m/s and15m/s,the maximum temperature in the temperature field is reduced,the range of the low temperature region is widened and the uniformity of the temperature field is improved.(3)Considering the full utilization of energy and based on the principle of energy saving,and the analysis of velocity field and temperature field,it can be concluded that the optical speed of cooling air is 14m/s.(4)Under the premise of 14m/s belowing speed,the low velocity range of the velocity field and the low temperature range of the temperature field all decrease after the addition of the baffle plate,and the temperature difference between inner and outer sides of the conveyor belt is also reduced.This study proved that the air supply speed is preferably 14m/s,and the addition of the baffle plate can further improve the distribution uniformity of the flow field and the temperature field. |
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