Heat Transfer from Single and Arrays of Impinging Water Jets(II)-1 Row of Impinging Water Jets-

Title & Authors
Heat Transfer from Single and Arrays of Impinging Water Jets(II)-1 Row of Impinging Water Jets-
Eom, Gi-Chan; Lee, Jong-Su; Geum, Seong-Min;

Abstract
Experiments have been conducted to obtain local and average heat transfer coefficients associated with impingement of a row of circular, free surface-water jets on a constant heat flux surface. Nozzle arrays are a row of 3 jets (nozzle dia.=4.6 mm) and a row of 5 jets (nozzle dia.=3.6 mm), and the nozzle configuration is Reverse cone type revealed good performance in heat transfer. Nozzle-to-plate spacings ranging from 16 mm to 80 mm were investigated for two jet center to center spacings 25 mm and 37.5 mm in the jet velocity of 3 m/s (R $\small{e_{D}}$=27000) to 8 m/s (R $\small{e_{D}}$=70000). For a row of 3 jets and a row of 5 jets, the stagnation heat transfer of the central jet is lower than that of adjacent jets. In the wall jet region between jets, for small nozzle-to-plate spacing and large jet velocity, the local maximum in the Nusselt number was observed, however, for small jet velocity or large nozzle-to-plate spacing, the local maximum was not observed. Except for the condition of $\small{V_{O}}$=8 m/s and H/D=10, the average Nusselt number reveals the following ranking: a row of 5 jets, a row of 3 jets, single jet. For a row of 3 jet, the maximum average Nusselt number occurs at H/D=8 ~ 10, and for a row of 5 jets, it occurs at H/D=2 ~ 4. Compared with the single jet, enhancement of average heat transfer for a row of 3 jets is approximately 1.52 ~ 2.28 times, and 1.69 ~ 3.75 times for a row of 5 jets.ets.s.
Keywords
Arrays of Impinging Water Jets;A row of 3 Jets;A row of 5 Jets;Enhancement of Heat Transfer;Nusselt Number;
Language
Korean
Cited by
1.
1열 원형 충돌수분류군에 의한 열전달의 실험적 연구 (제1보, 노즐형상의 영향),엄기찬;김상필;

설비공학논문집, 2000. vol.12. 1, pp.50-58
2.
1열 원형 충돌수분류군에 의한 열전달의 실험적 연구 (제2보, 노즐-전열면간 거리의 영향),엄기찬;이종수;김상필;

설비공학논문집, 2000. vol.12. 1, pp.59-66
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