Project Title:

Enhanced Cooling of Turbine Blades with Perforated Ribs

94-1	01.02	0017		

Enhanced Cooling of Turbine Blades with Perforated Ribs 

Abstract:

Gas turbines are required to operate with gas flows at temperatures 
more than 1400@C, much higher than the melting temperatures of 
blade material. Ribs cast in internal passages of blades for 
cooling, result in exorbitant pressure drops and extremely uneven 
heat transfer distribution. This is mainly due to the rib-induced 
"separation reattachment of cooling air". Perforated ribs are 
proposed for heat transfer augmentation. It is anticipated that the 
interaction between the flow through perforations and the main flow 
over the rib, can increase turbulence intensity near the wall, 
yielding enhanced and uniform heat transfer. The additional flow 
path provided by perforated ribs can also lower the penalty in 
pressure drops. The present investigation aims at obtaining the 
distribution of local heat transfer coefficients by using liquid 
crystal thermometry and understanding the complex interaction 
between two flows. The local distributions obtained will determine 
the extent of uniformity and enhancement of heat transfer. A square 
channel with ribs on two opposite walls simulating internal 
passages of blades will be employed. A wide number of operating and 
geometrical parameters for perforated ribs will be examined. 
Lynntech Inc., intends to adopt a dual-use approach for advanced 
cooling techniques, rendering them available for aircraft engines 
and industrial consumer-oriented applications.

The potential commercial applications for perforated ribs include 
gas turbine blades employed in aircraft engines and power plant 
utilities, heat exchangers for process and petrochemical 
industries, fuel rods in nuclear reactors, evaporator and 
condensers in refrigeration industries, tubes in boilers and heat 
recovery units, etc. 

Key Words

Lynntech, Inc.,	
7610 Eastmark Drive,
Suite 105,
College Station, TX 77840.