Title page for ETD etd-05252004-171602


Type of Document Master's Thesis
Author Prausa, Jeffrey Nathaniel
URN etd-05252004-171602
Title Heat Transfer Coefficient and Adiabatic Effectiveness Measurements for an Internal Turbine Vane Cooling Feature
Degree Master of Science
Department Mechanical Engineering
Advisory Committee
Advisor Name Title
Thole, Karen A. Committee Chair
O'Brien, Walter F. Jr. Committee Member
Vick, Brian L. Committee Member
Keywords
  • film cooling
  • microcircuit
  • internal cooling
  • heat transfer agumentation
  • gas turbines
  • friction augmentation
Date of Defense 2004-05-21
Availability unrestricted
Abstract
Aircraft engine manufacturers strive for greater performance and efficiency by continually increasing the turbine inlet temperature. High turbine inlet temperatures significantly degrade the lifetime of components in the turbine. Modern gas turbines operate with turbine inlet temperatures well above the melting temperature of key turbine components. Without active cooling schemes, modern turbines would fail catastrophically. This study will evaluate a novel cooling scheme for turbine airfoils, called microcircuit cooling, in which small cooling channels are located extremely close to the surface of a turbine airfoil. Coolant bled from the compressor passes through the microcircuits and exits through film cooling slots. On further cooling benefit is that the microcircuit passages are filled with irregular pin fin features that serve to increase convective cooling through the channels.

Results from this study indicate a strong interaction between the internal microcircuit features and the external film-cooling from the slot exit. Asymmetric cooling patterns downstream of the slot resulted from the asymmetric pin fin design within the microcircuit. Adiabatic effectiveness levels were found to be optimum for the slot design at a blowing ratio of 0.37. The pin fin arrangement along with the impingement cooling at the microcircuit entrance increased the area-averaged heat transfer by a factor of three, relative to an obstructed channel, over a Reynolds range of 5,000 to 15,000.

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