A method for the simultaneous determination of local effectiveness and heat transfer distributions in three-temperature convection situations
Abstract
An experimental method is described that enables the simultaneous determination of both local effectiveness and local heat-transfer information on surfaces involved in three-temperature convection situations, where the local surface temperature and heat transfer rate is under the influence of two interacting fluid streams at different temperatures. Film cooling through a single row of discrete flush-injection holes is used as the demonstration three-temperature situation, but the method is equally applicable to a wide variety of three-temperature situations. Two closely related transient experiments are conducted, and effectiveness and heat transfer are obtained as a simultaneous solution satisfying both data sets. The requisite information can be obtained with only a single transient test according to the measurement theory described, and reasonable improvements in the coating and experimental technique should make such tests feasible in the future. In all cases, the basic measured quantity is the time required for the local surface points to reach prescribed temperatures as indicated by a liquid-crystal color display, and the information is acquired through the use of video camera and computer vision system. The principal advantages of the method presented in comparison to other local measurement methods for three-temperature problems are the relatively simple and inexpensive surface preparation and the ready applicability to complex surface geometries.
- Publication:
-
36th ASME, International Gas Turbine and Aeroengine Congress and Exposition
- Pub Date:
- June 1991
- Bibcode:
- 1991gatu.confR....V
- Keywords:
-
- Film Cooling;
- Free Convection;
- Heat Transfer;
- Surface Temperature;
- Boundary Conditions;
- Liquid Crystals;
- Thermochromatic Materials;
- Fluid Mechanics and Heat Transfer