Heat Transfer Characteristics of an Angled Array Impinging Jet on a Concave Duct

Abstract

This study investigated the heat transfer characteristics of an array jet cooling system on a concave surface. Two types of injection holes were used: one for impinging jets normal to the impingement surface, and the other for angled impinging jets. For the normal jets, the jet Reynolds number (Re) based on the hole diameter varied from 3,000 to 10,000, and the height-to-diameter ratio (H/d) was fixed at 1.0. There were 15 injection holes positioned in a staggered 3×5 array. For the angled jets, Re was set to 5,000 and H/d was also fixed at 1.0. Naphthalene sublimation method was used to determine the heat transfer coefficients on the targeted plates. For normal impinging jet cooling, separate peaks were observed at the stagnation regions due to the curvature effect. Since a crossflow was generated by air spent from the jet arrays, the crossflow effect increased as it moved downstream. Due to the interaction between the crossflow and impinging jets, the peak values at the stagnation points increased downstream. The heat transfer coefficient on the targeted plate increased with Re. The average Sh of the angled jets was higher than that of the normal jets, as the obliquely impinging jet increased the mass flow rate and mass interaction between the jet impingement points.

Heat and Flow Characteristics of Aerofoil-Shaped Fins on a Curved Target Surface in a Confined Channel for an Impinging Jet Array

“…Different jet hole shapes [1][2][3][4], the arrangement of the jet holes [5][6][7][8], and the jet plate-target plate distances [3] were taken into account, and geometric optimization studies have been carried out in the literature. Additionally, Jung et al [1,9] compared the heat transfer characteristics of a standard and inclined jet array. Their findings showed that the inclined jet design exhibited higher heat transfer performance than the standard jet configuration.…”