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.