Title page for ETD etd-080399-154049


Type of Document Dissertation
Author Popp, Oliver
URN etd-080399-154049
Title Steady and Unsteady Heat Transfer in a Film Cooled Transonic Turbine Cascade
Degree PhD
Department Mechanical Engineering
Advisory Committee
Advisor Name Title
Ng, Fai Committee Chair
Diller, Thomas E. Committee Co-Chair
Dancey, Clinton L. Committee Member
Schetz, Joseph A. Committee Member
Wicks, Alfred L. Committee Member
Keywords
  • Unsteady Heat Transfer
  • Turbine
  • Film Cooling
  • Transonic Cascade
Date of Defense 1999-07-23
Availability unrestricted
Abstract
The unsteady interaction of shock waves emerging from the trailing edge of modern turbine nozzle guide vanes and impinging on downstream rotor blades is modeled in a linear cascade. The Reynolds number based on blade chord and exit conditions (5*10^6) and the exit Mach number (1.2) are representative of modern engine operating conditions. The relative motion of shocks and blades is simulated by sending a shock wave along the leading edges of the linear cascade instead of moving the blades through an array of stationary shock waves. The blade geometry is a generic version of a modern high turning rotor blade with transonic exit conditions. The blade is equipped with a showerhead film cooling scheme. Heat flux, surface pressure and surface temperature are measured at six locations on the suction side of the central blade. Pressure measurements are taken with Kulite XCQ-062-50a high frequency pressure transducers. Heat flux data is obtained with Vatell HFM-7/L high speed heat flux sensors. High speed heat flux and pressure data are recorded during the time of the shock impact with and without film cooling. The data is analyzed in detail to find the relative magnitudes of the shock effect on the heat transfer coefficient and the recovery temperature or adiabatic wall temperature (in the presence of film cooling).

It is shown that the variations of the heat transfer coefficient and the film effectiveness are less significant than the variations of recovery temperature. The effect of the shock is found to be similar in the cases with and without film cooling. In both cases the variation of recovery temperature induced by the shock is shown to be the main contribution to the overall unsteady heat flux.

The unsteady heat flux is compared to results from different prediction models published in the literature. The best agreement of data and prediction is found for a model that assumes a constant heat transfer coefficient and a temperature difference calculated from the unsteady surface pressure assuming an isentropic compression.

Files
  Filename       Size       Approximate Download Time (Hours:Minutes:Seconds) 
 
 28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access 
  ThesisMain.pdf 2.63 Mb 00:12:11 00:06:16 00:05:29 00:02:44 00:00:14

Browse All Available ETDs by ( Author | Department )

dla home
etds imagebase journals news ereserve special collections
virgnia tech home contact dla university libraries

If you have questions or technical problems, please Contact DLA.