ABSTRACT

The inclined impinging jets owing to higher efficiency are widely used to disperse concentrated and transient heat loads. The temperature and heat transfer characteristics of jet cooling vertical hot plate at different inclinations are experimentally investigated. Experiments are performed to investigate the area average heat transfer over a flat surface of 600 × 300 mm² placed at different location (z) of 3−20 d from the jet. The investigation is employed for Reynolds number based on hydraulic diameter of 11.5 mm ranging from 10,000 to 75,000. The orientation of the jet varies from 15° to 75°. The study aims to investigate the influence of jet orientation at different area locations on the surface from the point of impingement. The effect in stagnation region with different jet tilt is investigated. The area average temperature variation and characteristic temperature contours with increasing surface area and inclination is delineated. The characteristics of heat transfer on the surface’s periphery are studied. Heat transfer increases by 40% at lower tilt angle as the jet is displaced from 20 to 6 d, whereas the maximum average Nu occurs at higher inclination. The available Nusselt numbers in inclined jet are compared with present experimental results. A new empirical correlation is developed for a complete range of z/d, Re and large radial span.

摘要

倾斜冲击射流由于效率较高而被广泛用于分散集中和瞬态热负荷。对喷射冷却立式热板在不同倾角下的温度和传热特性进行了实验研究。^{进行实验以研究 600 × 300 mm 2}平坦表面上的面积平均传热放置在距离喷射 3−20 d 的不同位置 (z)。调查采用基于11.5毫米水力直径的雷诺数，范围为10,000至75,000。射流的方向从 15° 到 75° 不等。该研究旨在研究从撞击点开始的表面不同区域位置的射流方向的影响。研究了不同射流倾斜在停滞区的影响。描绘了随着表面积和倾斜度增加的区域平均温度变化和特征温度等值线。研究了表面周边的传热特性。当射流从 20 到 6 d 移动时，在较小的倾斜角度下，传热增加了 40%，而最大平均 Nu 出现在较高的倾斜角度。将倾斜射流中可用的努塞尔数与当前的实验结果进行了比较。针对 z/d、Re 和大径向跨度的完整范围开发了新的经验相关性。