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Internal Heat Transfer Experiments

Overview of CAD modelTest-section installed in fan spin pit

 

The goal of this research is to better understand heat transfer to the coolant flowing through the internal serpentine passages of a high-pressure turbine blade.  Heat transfer within these passages provides a significant fraction of the overall blade cooling, and a variety of techniques are used to enhance it such as the use of turbulators, pin-fin arrays, and unique turn geometries.  However, accurate (and timely) prediction of the heat transfer induced by these features remains a difficult challenge.

This experimental program provides data for a scaled-up blade geometry for appropriate ranges of Reynolds Number and Rotation Number.  Matching these parameters requires that the entire test section be able to rotate at speeds up to 3,000 RPM.  Comparisons for rotating and stationary situations, a variety of Reynolds Numbers, and different passage aspect ratios will help provide a more complete understanding of the governing flow physics.

In addition to providing valuable measurements, this experiment has also been a technology driver.  Preparing the test section to rotate at high-speed has required the development of new micro-electronics, structurally integrated circuitry, and mechanical assembly techniques.  Research in this area will continue to require the advancement of new measurement techniques to provide higher resolution data in a challenging environment.