技术中心

【中文摘要】 针对上下冲击式冻结装置在气流组织上的特点,利用CFD对该装置内静压箱和冻结区内的流场和温度场进行模拟计算。将冻品设置为内热源,运输冻品的网带作为多孔介质处理。通过改变位于冻品上下方的均风孔板开孔率得出:在静压箱内,随着出口开孔率的增大,风速逐渐减小,并且在由孔板和隔板间形成的局部区域内,压力分布逐渐趋于均匀;在冻结区内,通过速度场的模拟,从数值计算的角度验证了冷风在冻品表面产生的柯恩达效应。由温度场的模拟得到,冻品温度从冻结区入口至出口逐渐降低,孔板开孔率5%为最佳结构,可以使冻品在冻结终止时中心温度在-18℃以下,符合食品速冻的降温要求。 【英文摘要】 The numerical simulation of flow and temperature fields in the static pressure tank and the freezing area was performed with CFD technology based on the characteristics of airflow distribution in impingement freezers.Foodstuff and mesh belts were regarded as the inner heat source and the porous media,respectively.The results show that,in the static pressure tank,the air velocity decreased and the pressure distribution was uniform gradually in the corner between the plates and clapboards with the increase in the aperture of the perforated plates.Moreover,there was Coanda effect around the freezing food in the freezing area and the food temperature decreased from the inlet to the outlet of the freezing area.It is likely that the optimum rate of the opening aperture was 5%,which could ensure the center temperature of food below 18℃ at the end of freezing. 【中文关键词】 热工学; 速冻装置; 均风孔板; 上下冲击 【英文关键词】 Pyrology; Quick freezer; Perforated plates; Impingement 【基金】国家科技支撑计划资助项目(2006BAD30B01-08);; 上海市科技兴农重点攻关项目(沪农科攻字(2006)第7-1)资助~~ 【文献出处】 ,