NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Heat transfer and pressure drop in blade cooling channels with turbulence promotersRepeated rib roughness elements have been used in advanced turbine cooling designs to enhance the internal heat transfer. Often the ribs are perpendicular to the main flow direction so that they have an angle-of-attack of 90 deg. The objective of the project was to investigate the effect of rib angle-of-attack on the pressure drop and the average heat transfer coefficients in a square duct with two opposite rib-roughned walls for Reynolds number varied from 8000 to 80,000. The rib height-to-equivalent diameter ratio (e/D) was kept at a constant value of 0.063, the rib pitch-to-height ratio (P/e) was varied from 10 to 20, and the rib angle-of-attack (alpha) was varied from 90 deg to 60 deg to 45 deg to 30 deg respectively. Two types of entrance conditions were examined, namely, long duct and sudden contraction. The heat transfer coefficient distribution on the smooth side wall and the rough side wall at the entrance and the fully developed regions were measured. Thermal performance comparison indicated that the pumping power requirement for the rib with an oblique angle to the flow (alpha = 45 deg to 30 deg) was about 20 to 50 percent lower than the rib with a 90 deg angle to the flow for a given heat transfer duty.
Document ID
19850004007
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Han, J. C.
(Texas A&M Univ. College Station, TX, United States)
Park, J. S.
(Texas A&M Univ. College Station, TX, United States)
Lei, C. K.
(Texas A&M Univ. College Station, TX, United States)
Date Acquired
September 5, 2013
Publication Date
November 1, 1984
Publication Information
Publisher: NASA
Subject Category
Fluid Mechanics And Heat Transfer
Report/Patent Number
E-2249
NASA-CR-3837
NAS 1.26:3837
Accession Number
85N12315
Funding Number(s)
PROJECT: RTOP 505-31-4K
PROJECT: DA PROJ. 1L1-62209-AH-76
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
No Preview Available