Effect of permeable ribs on heat transfer and friction in a rectangular channel
- Chung-Hua Polytechnic Inst., Hsinchu (Taiwan, Province of China). Dept. of Mechanical Engineering
- National Tsing Hua Univ., Hsinchu (Taiwan, Province of China). Dept. of Power Mechanical Engineering
To increase specific thrust and to reduce specific fuel consumption (SFC), high turbine entry gas temperature (1,400--1,600 C) has become the trend in advanced aero-engine design. Such a high gas temperature is far above the allowable metal temperature; therefore, turbine blades must be cooled in order to operate in the high gas temperature environment. Heat transfer and friction characteristics in a rectangular channel with perforated ribs arranged in-line on two opposite walls are investigated experimentally. Five perforated rib open-area ratios (0, 10, 22, 38, and 44%) and three rib pitch-to-height ratios (10, 15, and 20) are examined. The Reynolds number ranges from 5,000 to 50,000. The rib height-to-channel hydraulic diameter ratio and the channel aspect ratio are 0.081 and 4, respectively. Laser holographic interferometry is employed not only to measure the heat transfer coefficients of the ribbed wall but also to determine the rib apparent permeability. It is found that ribs with appropriate high open-area ratio and high Reynolds number are permeable, and the critical Reynolds number for evidence of flow permeability decreases with increasing rib open-area ratio. Results of local heat transfer coefficients further show that the permeable ribs have an advantage of obviating hot spots. Moreover, the duct with permeable ribs gives a higher thermal performance than that with solid ribs.
- OSTI ID:
- 55498
- 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
Similar Records
Heat transfer and friction characteristics in rectangular channels with rib turbulators
An experimental investigation of heat transfer characteristics for turbulent flow over staggered ribs in a square duct