Effects of freestream turbulence on turbine blade heat transfer in transonic flow

The effects of grid generated freestream turbulence on surface heat transfer to turbine blades were measured experimentally. Time-resolved and unsteady heat flux measurements were made with Heat Flux Microsensors at two positions on the suction side of turbine blades. The experiments were conducted on a stationary cascade of aluminum turbine blades for heated runs at transonic conditions. Non-dimensional flow parameters were matched to actual engine conditions including the design exit Mach number of 1.26 and the gas-to-wall temperature ratio of 1.4. Methods for determining the adiabatic wall temperature and heat transfer coefficient are presented and the results are compared to computer predictions for these blades. Heat transfer measurements were taken with a new, directly deposited HFM gage near the trailing edge shock on nitrogen cooled blades. The average heat transfer coefficient for Mach 1.26 was 765 W/(m² °C) and matched well with a predicted value of 738 W/(m² °C). Freestream turbulence effects were studied at a second gage location 1.0 cm from the stagnation point on uncooled blades. Results at this location show an increase in freestream turbulence from 1 % to 8% led to a 15% increase of the average heat transfer coefficient and also matched well with predictions. The fast response time of the HFM illustrated graphically the increase in energy spectra due to freestream turbulence at the 0 - 10kHz range. The heat flux turbulence intensity (Tu_q) was defined as another physical quantity important to turbine blade heat transfer.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Mechanical Engineering

Department dc:contributor.department

Mechanical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1995

Author dc:creator

• Johnson, Loren Patton

Chairs dc:contributor.committeechair

• Diller, Thomas E.
• Ng, Fai

Committee member dc:contributor.committeemember

• Nelson, Douglas J.

• heat flux measurements

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

etd-01312009-063212

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/40836