Glenn-HT is a computational fluid dynamics (CFD) computer code for the analysis of three-dimensional flow and convective heat transfer in a gas turbine. Glenn-HT has been evolving during the past few years at Glenn Research Center, and at least 35 technical papers relative to this code have been published. The code is unique in the ability to give highly detailed representations of flow fields very close to solid surfaces. This ability is necessary for obtaining accurate representations of fluid heat transfer and viscous shear stresses.

The computation of convective heat transfer in a gas-turbine environment is a very difficult task, but one that must be done with reasonable accuracy in order to design a durable engine. Three-dimensional CFD computer codes are used extensively to determine pressure distributions in turbines, but the determination of heat transfer is a much more complex problem, in which it is necessary to consider details of flow fields very close to solid walls. Glenn-HT has been specifically developed to address this issue. The unique feature of this code is the use of a multiblock grid system that enables the use of high-quality grid structures very close to walls, eliminating the need for wall functions for calculating heat transfer. A conventional aspect of the code is the inclusion of a two-equation k-ω model (a k-ω model is a mathematical model of turbulence in which k denotes the turbulent kinetic energy, while ω denotes the fractional rate of dissipation of the k).

The code has been used extensively to perform cooling-passage-flow and hot-gas-path-flow calculations, including detailed calculations of film cooling and of complex tip-clearance-gap flow and heat transfer. The code has been validated for a number of turbine configurations. Although developed and used primarily as a research tool, the code should be useful for detailed design analysis.

This work was done by James D. Heidmann of Glenn Research Center, Ali A. Ameri and Vijay K. Garg of AYT Corp., David L. Rigby of NYMA/Dynacs, and Erlendur Steinhorsson of OAI. LEW-16765


NASA Tech Briefs Magazine

This article first appeared in the November, 1999 issue of NASA Tech Briefs Magazine.

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