HEAT TRANSFER EFFECTS OF NON-TRADITIONAL FILM COOLING HOLE GEOMETRIES ON COOLING EFFECTIVENESS

Open Access
Author:
Sun, Emily J
Area of Honors:
Mechanical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Stephen P Lynch, Thesis Supervisor
  • Stephanie Stockar, Honors Advisor
Keywords:
  • film cooling
  • geometry
  • curved meter
  • shaped holes
  • adiabatic film cooling effectiveness
  • effectiveness
  • bent meter
  • shaped hole
  • cross-section
Abstract:
A gas turbine is a device that harnesses energy from the manipulation of air. In pursuit of greater efficiencies, the temperatures of the combustors are being increased. Given these conditions, certain design steps and materials selection are vital for the performance of the components. On the design side, internal and external cooling features can be designed to control the heat transfer to and from a part. Film cooling is a mechanism by which some of the internal cooling flow is allowed to flow over the surface of the airfoil of a turbine blade via holes in the wall of the turbine blade. Currently film cooling hole geometry designs are usually drilled through the walls of the airfoil through laser drilling or electro discharge machining (EDM). With this method of creating the film cooling holes, the designs for these holes needs to fall along a linear axis and tool-paths must be considered. However, with the development of additive manufacturing, turbine blades can be constructed with film cooling holes already embedded in the designs. As a result, the designs for film cooling holes have a greater complexity tolerance, which can be used to optimize the internal fluid dynamics. In order to explore the effects of the complex film cooling geometries, various film cooling hole geometries have been designed. The major designs were different modification of the 7-7-7 hole. The two types of design modifications were to the cross section or the curvature of the meter. The four major designs were: the Square hole, the Half Circle hole, the 60 Turn hole, and the 90 Turn hole. An experiment was conducted to determine the effect of the different changes on film cooling effectiveness in comparison to the 7-7-7 hole.