In the present work, heat and mass transfer from different foods by impinging a slot hot air jet at low Reynolds numbers is numerically researched. Banana and apples are selected as foods due to their trading importance. Low Reynolds numbers are operated as Re = 100, 200 and 300. The diameters of the foods and initial jet height are taken as fixed in all examined situations and the impinging jet is laminar and two-dimensional. The shape of foods is assumed as a cylinder. The distance (D/H) between the cylinder and the slot is taken as another effective parameter of drying process and it is used with the three different distances (D/H = 0.22, 0.25, and 0.33) to search jet effectiveness on heat and mass transfer. A finite volume method is employed to solve governing equations of mass, momentum and energy by means of ANSYS Fluent 17.0 program. There is a good agreement with the numerical and experimental data available in the literature. The heat transfer increments and temperature variations for different Reynolds number values and for varying distance, D/H, and also temperature and mass distributions are researched for both inside the foods. It is obtained that heat and mass transfer enhanced with reducing the distance, D/H, between the jet and the cylinder. In addition, locally, the most effective jet drying is achieved close to the stagnation point on the front face of the foods.

中文翻译：

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低雷诺数干燥过程中射流对不同食品的传热传质计算分析

在目前的工作中，通过以低雷诺数撞击狭缝热空气射流，对不同食物的热量和质量传递进行了数值研究。香蕉和苹果因其贸易重要性而被选为食品。低雷诺数的操作方式为Re = 100、200和300。在所有检查的情况下，食物的直径和初始射流高度均固定不变，并且撞击射流是层流和二维的。食物的形状假定为圆柱体。滚筒与缝隙之间的距离（D / H）被视为干燥过程的另一个有效参数，并与三个不同的距离（D / H = 0.22、0.25和0.33）一起使用，以搜索射流对热量和热量的有效性。传质。通过ANSYS Fluent 17.0程序，采用有限体积法求解质量，动量和能量的控制方程。与文献中可用的数值和实验数据有很好的一致性。对于食物内部，都研究了不同雷诺数值和不同距离，D / H的传热增量和温度变化，以及温度和质量分布。可以看出，随着射流与气缸之间的距离D / H的减小，传热和传质得到了增强。另外，局部地，在食品正面的停滞点附近实现了最有效的喷射干燥。可以看出，随着射流与气缸之间的距离D / H的减小，传热和传质得到了增强。另外，局部地，在食品正面的停滞点附近实现了最有效的喷射干燥。可以看出，随着射流与气缸之间的距离D / H的减小，传热和传质得到了增强。另外，局部地，在食品正面的停滞点附近实现了最有效的喷射干燥。