Surface heating effect on local heat transfer in a rotating two-pass square channel with 60 deg angled rib turbulators

Journal Article · Sat Apr 01 04:00:00 EST 1995 · Journal of Turbomachinery

DOI:https://doi.org/10.1115/1.2835656· OSTI ID:55499

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

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

The influence of uneven wall temperature on the local heat transfer coefficient in a rotating, two-pass, square channel with 60 deg ribs on the leading and trailing walls was investigated for Reynolds number from 2,500 to 25,000 and rotation numbers from 0 to 0.352. Each pass, composed of six isolated copper sections, had a length-to-hydraulic diameter ratio of 12. The mean rotating radius-to-hydraulic diameter ratio was 30. Three thermal boundary condition cases were studied: (A) all four walls at the same temperature, (B) all four walls at the same heat flux, and (C) trailing wall hotter than leading with side walls unheated and insulated. Results indicate that rotating ribbed wall heat transfer coefficients increase by a factor of 2 to 3 over the rotating smooth wall data and at reduced coefficient variation from inlet to exit. As rotation number (or buoyancy parameter) increases, the first pass (outflow) trailing heat transfer coefficients increase and the first pass leading heat transfer coefficients decrease, whereas the reverse is true for the second pass (inflow). The direction of the Coriolis force reverse from the outflow trailing wall to the inflow leading wall. Differences between the first pass leading and trailing heat transfer coefficients increase with rotation number. A similar behavior is seen for the second pass leading and trailing heat transfer coefficients, but the differences are reduced due to buoyancy changing from aiding to opposing the inertia force. The results suggest that uneven wall temperature has a significant impact on the local heat transfer coefficients. The heat transfer coefficients on the first pass leading wall for cases B and C are up to 70--100% higher than that for case A, while the heat transfer coefficients on the second pass trailing wall for cases B and C are up to 20--50% higher.

• Sponsoring Organization: USDOE
• OSTI ID: 55499
• Report Number(s): CONF-930502--
• Journal Information: Journal of Turbomachinery, Journal Name: Journal of Turbomachinery Journal Issue: 2 Vol. 117; ISSN JOTUEI; ISSN 0889-504X
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
COOLING
DUCTS
FUEL CONSUMPTION
HEAT TRANSFER
PERFORMANCE
TURBINE BLADES
TURBULENT FLOW