HEAT-TRANSFER AND FLOW PATTERN AT A CYLINDER IMPINGED BY A SLOT JET DURING INCIPIENT AND NUCLEATE BOILING

The heat transfer due to a submerged slot jet of water impinging on a circular cylinder in cross flow was experimentally studied in the regi on of incipient and fully developed nucleate boiling. The diameter of the cylinder and the width of the jet are the same-namely, 3 mm. The h eat flux ranged from 4 x 10(4) to 1.5 x 10(6) W/m(2). The effects of t he jet velocity and of the fluid subcooling were investigated in the r ange 0.37 less than or equal to v 1.11 m/s and 0 less than or equal to (Delta T)(sub) less than or equal to 15 K, both in upward and downwar d flow. The results showed that the influence of these parameters is l imited to the region of incipient boiling, whereas, in fully developed boiling, all the boiling curves merge into a single one. A photograph ic study of the bubble flow pattern evidenced a different behavior wit h respect to cylinders in uniform cross flow. (C) Elsevier Science Inc ., 1997.