Title page for ETD etd-05192003-115253


Type of Document Master's Thesis
Author Hohlfeld, Erik Max
Author's Email Address ehohlfel@vt.edu
URN etd-05192003-115253
Title Film Cooling Predictions Along the Tip and Platform of a Turbine Blade
Degree Master of Science
Department Mechanical Engineering
Advisory Committee
Advisor Name Title
Thole, Karen A. Committee Chair
Dancey, Clinton L. Committee Member
Tafti, Danesh K. Committee Member
Keywords
  • gas turbines
  • microcircuit
  • tip gap
  • platform
  • blade heat transfer
  • film-cooling
Date of Defense 2003-05-08
Availability unrestricted
Abstract
Turbine airfoils are exposed to the hottest temperatures in the gas turbine with temperatures typically exceeding the melting point of the blade material. Cooling methods investigated in this computational study included parasitic cooling flow losses, which are inherent to engines, and microcircuit channels. Parasitic losses included dirt purge holes, located along the blade tip, and platform leakage flow, which result from gaps between various turbine components. Microcircuits are a novel cooling technique involving small air passages placed near the airfoil surface to enhance internal cooling. This study evaluated the benefit of external film-cooling flow exhausted from strategically placed microcircuits.

Along the blade tip, predictions showed mid-chord cooling was independent of the blowing from microcircuit exits. The formation of a pressure side vortex was found to develop for most microcircuit film-cooling cases. Significant leading edge cooling was obtained from coolant exiting from dirt purge holes with a small tip gap while little cooling was seen with a large tip gap.

Along the blade platform, the migration of coolant from the front leakage was shown to cool a considerable part of the platform. Several hot spots were predicted along the platform, which were circumvented through the placement of microcircuit channels. Ingestion of hot mainstream gas was predicted along the aft portion of the gutter and agreed with distress exhibited by actual gas turbine engines.

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  Appendix.pdf 5.48 Mb 00:25:23 00:13:03 00:11:25 00:05:42 00:00:29
  Part_I.pdf 3.57 Mb 00:16:32 00:08:30 00:07:26 00:03:43 00:00:19
  Part_II.pdf 2.53 Mb 00:11:42 00:06:01 00:05:16 00:02:38 00:00:13
  Part_III.pdf 30.66 Mb 02:21:57 01:13:00 01:03:53 00:31:56 00:02:43
  Part_IV.pdf 9.50 Mb 00:43:59 00:22:37 00:19:47 00:09:53 00:00:50

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