An Experimental Film Cooling Effectiveness Introducing a New Film Hole Geometry Using Pressure Sensitive Paint Technique
[Thesis]
Yao, Yuan
Taslim, Mohammad E.
Northeastern University
2019
210 p.
M.S.
Northeastern University
2019
Since the invention of the gas turbine technology, countless engineers and scientists have been trying their best to refine this type of machine. One of the most difficult problems associated with the design of a gas turbine is the thermal protection for the turbine airfoils. For airfoil surface, the most efficient way of thermal protection is film cooling which is the focus of this thesis. Film cooling is spreading a coolant over the hot airfoil surfaces and creating a blanket of the cooling air over that surface to protect it from the incoming hot gases from the combustion chamber. To accomplish this task, different hole angles and shapes are employed. In this thesis, two new 'V-shaped' film cooling hole, which combine anti-counter-rotating vortices (ACRV) with normal film cooling concept, are tested for film cooling effectiveness comparison with a 7-7-7-degree fan-shaped film cooling hole and the original baseline cylindrical film holes. Pressure Sensitive Paint (PSP) technology is used to measure the film cooling effectiveness, which is a fairly new and accurate technique for film cooling studies. The main conclusion is: (1) Both 'V-shaped' hole geometries can significantly resist the influence of the counter-rotating vortex pair and make the flow retouch the surface. (2) V60-shaped design shows the highest film cooling effectiveness at high blowing ratio ratios. (3) The V-shaped film cooling holes tested in this study show almost the same results at high blowing ratios.