SBIR 95-1 SOLICITATION

PROJECT SUMMARY

Contract Id:

NAS 3 27739

Proposal Number:

01.02-0017

Project Title:

HEAT TRANSFER ENHANCEMENT IN TURBINE BLADES WITH ASYMMETRIC RIBS

Technical Abstract:

Gas turbines are required to operate with gas flows at temperatures more than 1400oC, much higher than the melting temperatures of the blade material. The Coriolis force, induced by rotation of turbine blades, results in highly non-uniform heat transfer distribution on leading and trailing sides, leading to premature failure and unreliable thermal operation of the blade. This is mainly due to the distortion of mainstream velocity profile by cross-stream secondary flows. To combat this problem, use of Asymmetric ribs are proposed for heat transfer augmentation, namely, thicker ribs on trailing side and thinner ribs on leading side. It is anticipated that higher shear stress along the leading wall and lower shear stress on the leading wall, enforced by asymmetric ribs, will yield enhanced and more uniform heat transfer. The proposed investigation aims at obtaining uniform distributions of regional and local heat transfer coefficients through mass transfer experiments and by using the analogy between heat and mass transfer. Extensive experiments will be conducted with transverse and angled, asymmetric ribs in a two-pass, square rotating channel. The local distributions obtained will determine the extent of uniformity and enhancement of heat transfer with asymmetric ribs. A wide number of operating and geometrical parameters will be examined. The proposed Phase I project will identify the best rib configuration that can yield enhanced and more uniform heat transfer in turbine blades.

Potential Commercial Applications:

The for asymmetric ribs include gas turbine blades for aircraft engines and rotors of electrical rotating machinery. It will lead to higher power output, higher thermal efficiency, and increased life cycle of gas turbine engines and turbomachinery.

Name and Address of Offeror:

Lynntech, Inc
7610 Eastmark Drive, Suite 105
College Station, Texas 77840