为研究不同喷口结构时速冻机内流动和换热特性、优化速冻机的气流组织和提高换热效率，以冲击式速冻机为研究对象，设计了5种不同形式的条缝喷口，分别对这5种喷口喷射气流流动和换热特性进行数值模拟，对比分析喷射区域的气流组织，研究了被冲击的板带表面的温度场分布和Nu变化。研究表明：孔板式喷口的流量较小，为167.9 m3/h，换热的均匀性较差；组合式渐缩喷口的气流组织最佳，喷口出口的流量最大，为226.2 m3/h，同时板带表面的平均Nu也最高，达到29.6。

The impingement Freezer is an innovative food freezing technology which uses high velocity and low temperature air to freeze food.The air distribution of jetting area in impingement freezer was investigated numerically to improve the flow and heat transfer of the impingement freezer.Five jets were designed for the impingement freezer,and the flow and heat transfer characteristics were studied.The air distributions of five jets were compared,and the temperature distributions and Nu numbers of baseplates in impingement freezer were shown in the paper.The results showed that the conventional jet plate has the lowest mass flux and worst uniformity of heat transfer.The combined convergent nozzle has the best air distribution,highest mass flux (226.2 m3/h),and also the highest average Nu number of baseplatehighest at 29.6.

TS205.7

国家“十三五”重点研发项目（2016YFD0400303）；上海高校青年教师培养资助计划（ZZSHOU16013）；上海海洋大学博士科研启动基金（A2-0203-17-100317）；上海海洋大学科技发展专项基金（A2-0203-17-100207）