Accession Number : ADA328807
Title : Complementary Velocity and Heat Transfer Measurements in a Rotating Turbine Cooling Passage.
Descriptive Note : Doctoral thesis,
Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
Personal Author(s) : Bons, Jeffrey P.
PDF Url : ADA328807
Report Date : 22 AUG 1997
Pagination or Media Count : 200
Abstract : An experimental investigation was conducted on the internal flowfield of a simulated turbine blade cooling passage. The passage is of a square cross-section and was manufactured from quartz for optical accessibility. Velocity measurements were taken using Particle Image Velocimetry for both heated and non-heated cases. Thin film resistive heaters on the four passage walls allow heat to be added to the coolant flow without obstructing laser access. Under the same conditions, an infrared detector with associated optics collected wall temperature data for use in calculating local Nusselt number. The test section was operated with radial outward flow and at values of Reynolds number, Rotation number, and density ratio typical of applications. Velocity data for the non-heated case document the evolution of the Coriolis-induced double vortex. The vortex has the effect of increasing the leading side boundary layer thickness while decreasing the trailing side boundary layer thickness. Also, the streamwise component of the Coriolis acceleration creates a thinned side wall boundary layer. These data reveal an unsteady, turbulent flowfield in the cooling passage. Velocity data for the heated case show a strongly distorted streamwise profile indicative of a buoyancy effect on the leading side. The Coriolis vortex is the mechanism for the accumulation of stagnant flow on the leading side of the passage. Heat transfer data show a maximum factor of two difference in the Nusselt number from trailing side to leading side. An estimate of this heat transfer disparity based on the measured boundary layer edge velocity yields approximately the same factor of two. A momentum integral model was developed for data interpretation which accounts for Coriolis and buoyancy effects. Calculated streamwise profiles and secondary flows match the experimental data well.
Descriptors : *HEAT TRANSFER, *TURBINE BLADES, SIMULATION, OPTICAL PROPERTIES, THIN FILMS, THESES, TURBULENT FLOW, VORTICES, LASERS, COOLING, QUARTZ, FLOW FIELDS, CROSS SECTIONS, INFRARED DETECTORS, VELOCIMETERS, REYNOLDS NUMBER, MOMENTUM, BUOYANCY, STAGNATION, RADIAL FLOW, SECONDARY FLOW, CORIOLIS EFFECT.
Subject Categories : Fluid Mechanics
Jet and Gas Turbine Engines
Distribution Statement : APPROVED FOR PUBLIC RELEASE