Heat Transfer from Single and Arrays of Impinging Water Jets(I)-Single Water Jet-

Title & Authors
Heat Transfer from Single and Arrays of Impinging Water Jets(I)-Single Water Jet-
Eom, Gi-Chan; Lee, Jong-Su; Yu, Ji-O;

Abstract
The heat transfer characteristics of free surface water jet impinging normally against a flat uniform heat flux surface were investigated. This deals with the effect of three nozzle configurations (Cone type, Reverse cone type, Vertical circular type) on the local and the average heat transfer. Heat transfer measurements were made for water jet issuing from a nozzle of which exit diameter 8 mm. The experimental conditions investigated are Reynolds number range of 27000 ~ 70000( $\small{V_{O}}$=3 ~ 8 m/s), nozzle-to-target plate distances H/D=2 ~ 10, and radial distance from the stagnation point r/D ~ = 0 ~ 7.42. For all jet velocities of H/D=2, the local Nusselt number decreased monotonically with increasing radial distance. However, for H/D from 4 to 10, and for the jet velocity $\small{V_{O}}$.geq.7 m/s for Cone type nozzle and $\small{V_{O}}$.geq.6 m/s for the other type nozzles, the Nusselt number distributions exhibited secondary peaks at r/D=3 ~ 3.5. For Reverse cone type nozzle and Vertical circular nozzle, the maximum stagnation point heat transfer and the maximum average heat transfer occurs at H/D=8. But for the Cone type nozzle, the maximum stagnation and average heat transfer occurs at H/D=10, 4, respectively. From the optimum nozzle-to-target plate distance, the stagnation and the average heat transfer reveal the following ranking: Reverse cone type nozzle, Vertical circular type nozzle, Cone type nozzle.ozzle.
Keywords
Impinging Water Jet;Cone Type Nozzle;Reverse Cone Type Nozzle;Vertical Circular Type Nozzle;Single Water Jet;Nusselt Number;
Language
Korean
Cited by
1.
단일수분류 및 수분류군에 의한 열전달(2)-1열 수분류군-,엄기찬;이종수;금성민;

대한기계학회논문집B, 1997. vol.21. 9, pp.1115-1125
2.
1열 원형 충돌수분류군에 의한 열전달의 실험적 연구 (제1보, 노즐형상의 영향),엄기찬;김상필;

설비공학논문집, 2000. vol.12. 1, pp.50-58
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