Design and calibration of a local heat-flux measurement system for unsteady flows
A local heat-flux measurement system was built, calibrated, and testedfor use in unsteady flows. The system was designed to maintainconstant-wall-temperature boundary conditions. The measuring element is athin-film heat flux gage made by sputter-coating gold onto a substrate.A constant-temperature anemometer is used to maintain the thin-film gage at aspecified temperature under fluctuating conditions. A separate temperaturecontrol system maintains the surrounding boundary at the gage temperature.The system was calibrated for both steady and unsteady flows using a speciallydesigned calibrator for local heat flux gages. The steady calibration was donewith predominantly convective heat transfer. The unsteady calibration wasachieved by adding oscillating radiant energy to the surface. Consequently,quantitative result can be obtained for both the mean and fluctuating componentsof the heat transfer. The frequency response was good to over 90 H/ital z/.Sample results are presented of the unsteady heat transfer over a circularcylinder caused by natural vortex shedding at 70 to 80 H/ital z/.
- Research Organization:
- Mchanical Engineering Department, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061(US)
- OSTI ID:
- 6217166
- Journal Information:
- J. Heat Transfer; (United States), Journal Name: J. Heat Transfer; (United States) Vol. 111:2; ISSN JHTRA
- Country of Publication:
- United States
- Language:
- English
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