The objective of the present work is to measure the local heat transfer coefficient for an unconfined slot air jet impinging on a metal foamed flat plate having different pore densities using a thin metal foil technique. The enhancement of the heat transfer caused by the metal foamed flat plate in comparison with a smooth flat plate is measured. The experiments are performed for the Reynolds number (based on slot width) ranging from 5200 to 12,000, and nozzle to plate spacing varied from 2 to 10 times the slot width. Aluminium foams having a porosity of 92% and a pore density of 10, 20, and 40 pores per inch (PPI) are used. The thickness of the metal foam is 8 mm. An infrared camera is used to measure the local temperature distribution of the metal foamed flat plate. A metal foamed flat plate enhances the stagnation Nusselt number and the average Nusselt number compared to the smooth flat plate irrespective of the pore density. The local Nusselt number is highest in the stagnation region and decreases in the streamwise direction. A metal foamed flat plate with a pore density of 40 PPI results in lower augmentation of the stagnation and average Nusselt number compared to a metal foamed flat plate with a pore density of 10 PPI and 20 PPI. Metal foamed flat plates with a pore density of 10PPI, and 20 PPI show almost the same stagnation Nusselt Number and average Nusselt number. The average and the stagnation Nusselt numbers are less sensitive to the nozzle to plate spacing for a metal foamed flat plate. Empirical correlations for the local Nusselt number for three different regions based on the Reynolds number $\left(Re\right)$, non-dimensional streamwise distance $\left(x/b\right)$ and nozzle to plate spacing $\left(z/b\right)$ are proposed.

本工作的目的是使用薄金属箔技术测量撞击在具有不同孔隙密度的金属泡沫平板上的无侧限狭缝空气射流的局部传热系数。与光滑的平板相比，测量了由金属泡沫平板引起的传热增强。实验针对雷诺数（基于狭缝宽度）范围从 5200 到 12,000 以及喷嘴与板间距从狭缝宽度的 2 倍到 10 倍变化而进行。所使用的泡沫铝具有 92% 的孔隙率和 10、20 和 40 个孔/英寸 (PPI) 的孔密度。金属泡沫的厚度为8mm。红外热像仪用于测量金属泡沫平板的局部温度分布。与光滑平板相比，无论孔密度如何，金属泡沫平板都提高了停滞努塞尔数和平均努塞尔数。局部努塞尔数在停滞区最高，沿流向减小。与孔密度为10 PPI和20 PPI的金属泡沫平板相比，孔密度为40 PPI的金属泡沫平板导致较低的停滞和平均努塞尔数的增加。孔密度为10PPI和20PPI的金属泡沫平板显示出几乎相同的停滞努塞尔数和平均努塞尔数。对于金属泡沫平板，平均和停滞努塞尔数对喷嘴与板间距的敏感度较低。基于雷诺数的三个不同区域的局部努塞尔数的经验相关性$\left(\mathrm{电阻}\mathrm{电子}\right)$, 无量纲流向距离 $\left(X/乙\right)$ 和喷嘴到板的间距 $\left(z/乙\right)$ 被提议。