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An Experimental Investigation of Flow Characteristics with Film Cooling Holes on Turbine Blade Leading Edge

Author: QuHongWei
Tutor: LiShaoHua
School: Tohoku Electric Power University
Course: Thermal Power Engineering
Keywords: Low speed blow down wind tunnel Film cooling Blowing ratio Blade curvature Experiment investigation
CLC: TK473
Type: Master's thesis
Year: 2011
Downloads: 36
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Abstract

Film cooling technology as one of the most effective means of protecting the turbine blades is widely used in modern high load aircraft engines .Numerical simulation and experiment are two mainly methods for film cooling research. The conclusions in this thesis were based on the results of previous experiments that was done in the Wind Tunnel Laboratory in Northeast Dian Li University. Firstly , the hot-film anemometer was used to measure the field of film cooling with a round hole at the jet injection angle of 90°in a flat plate .Secondly we use the blade named MARKⅡthat was released by NASA Levis Gas Turbine Research Center, because the size of the blade was too small, so under the experimental conditions the measurement deviation may be large, in order to decrease the deviation we magnified 2 times of the blade according to the principle of similarity theory. Under the condition that the mainstream velocity to be 10 m/s and the Renolds number based on the chord length of the blade was 160000. The Hot-film anemometer was used to measure the D speed u、v, and turbulent kinetic energy along circumferential direction distribution that downstream of the film cooling holes on the suction side and the pressure side. Also we chose M=0.5 and 1.5 for blowing ratio, the very position of film cooling holes on the suction and the pressure side are x/d = 4,8,15 and 25. All of these aim to further the study of the flow adherent to the wall mechanism thoughtfully.Experimental upper leaves can be rotated,so the blade installation angle can be changed in the experimental section. The concept success to solve the re-use of section leaves. We can remove experimental film cooling holes and change the geometric parameters randomly. The study provided convenience for future scholars .According to the experiment results. When the blowing ratio on the suction side and the pressure side increase, the mainstream and the jet injection mixing center also rise. Entrainment flow occurs at the position of the blade surface with great curvature gradient and simultaneously the mixing flow has a wicked adherent to the wall. The velocity gradient of the u velocity that on the suction side was increasing significantlly, also the level of the adherent to the wall was better than the pressure side. With the x/d increasing, the velocity u on the pressure side gradually becomed irregularly, also the secondary flow occurs near the wall region which has the great curvature. The blowing ratio on the suction side has a little influence on velocity v than on the pressure side. On the pressure surface, as x/d increases, the maximum value of turbulent kinetic energy moves away from the wall with the same blowing ratio, at the same time the maximum value of turbulent kinetic energy decreases. Near the wall, turbulent kinetic energy on the suction surface change less obviously than the pressure side. The value of turbulent kinetic energy in the blade trailing edge region varies, but the magnitude is much smaller than the pressure side. With the blowing ratio increasing, the maximum turbulent kinetic energy is on the rise, but not very obvious.

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CLC: > Industrial Technology > Energy and Power Engineering > Internal combustion engine > Gas turbine ( gas turbine ) > Structure
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