Influence of surface heating condition on local heat transfer in a rotating square channel with smooth walls and radial outward flow

Conference · Sat Jan 01 04:00:00 EST 1994 · Journal of Turbomachinery; (United States)

OSTI ID:5069473

Han, J C; Zhang, Y M ^[1]; Lee, C P ^[2]

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1. Texas A M Univ., College Station, TX (United States). Dept. of Mechanical Engineering
2. General Electric Co., Cincinnati, OH (United States)

The effect of a surface heating condition on the local heat transfer coefficient in a rotating square channel with smooth walls and radial outward flow was investigated for Reynolds numbers from 2,500 to 25,000 and rotation numbers from 0 to 0.352. The square channel, composed of six isolated copper sections, has a length-to-hydraulic diameter ratio of 12. The mean rotating radius to the channel hydraulic diameter ratio is kept at a constant value of 30. Four surface heating conditions were tested: (1) four walls at uniform temperature, (2) temperature ratio of leading surface to side wall and trailing surface to side wall is 1.05 and 1.10, respectively, (3) trailing surface hot and remaining three walls cold, and (4) leading surface not and remaining three walls cold. The results show that the heat transfer coefficients on the leading surface are much lower than that of the trailing surface due to rotation. For case (1) of four walls at uniform temperature, the leading surface heat transfer coefficient decreases and then increases with increasing rotation numbers, and the trailing surface heat transfer coefficient increases monotonically with rotation numbers. However, the trailing surface heat transfer coefficients for cases (2) and (3) are slightly lower than case (1), and the leading surface heat transfer coefficients for cases (2) and (4) are significantly higher than for case (1). The results suggest that the local wall heating condition creates the local buoyancy forces, which reduce the effects of the bulk buoyancy and Coriolis forces. Therefore, the local heat transfer coefficients on the leading and trailing surfaces are altered by the surface local heating condition.

• OSTI ID: 5069473
• Report Number(s): CONF-920602--
• Conference Information: Journal Name: Journal of Turbomachinery; (United States) Journal Volume: 116:1
• Country of Publication: United States
• Language: English

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