THEORETICAL ANALYSIS OF COOLING EFFECT ON THE EFFECTIVENESS OF GAS TURBINE BLADES | ||||
| ERJ. Engineering Research Journal | ||||
| Article 7, Volume 32, Issue 3, July 2009, Page 305-318 PDF (672.13 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/erjm.2009.69346 | ||||
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| Authors | ||||
| M. Khalil Bassiouny1; S. A. Wilson1; M. F. Mosa2 | ||||
| 1Mechanical Power Engineering Department Faculty of Engineering, Minoufiya University, | ||||
| 2Mechanical Power Engineering Department Faculty of Engineering, Minoufiya University | ||||
| Abstract | ||||
| The modem gas turbine engines operate at high pressure ratio and consequently higher entry turbine temperatures. At high loads, this temperature exceeds the allowable metal-temperature limits. The turbine blades need to be protected to ensure theft integrity. The efficient cooling technique such as film cooling is therefore essential to protect the gas turbine blades. The efficiency of this technique depends on several parameters, such as the injection blowing ratio, density ratio, mainstream turbulence intensity, mainstream pressure gradient, boundary layer thickness, injection angle, spacing between holes as well as their arrangement, and the blade geometry. The main objective of this study was to make a numerical study on the first stage for both profiles VKI and C3X turbine blades cascade with a leading edge showerhead film-cooling arrangement by using the commercial code Fluent v. 5.4. The governing equations for steady, t~vo dimensional, turbulent, compressible flow are integrated over arbitrary two-dimensional control volumes with the aid of Gauss theorem. The present computational model seeks to a realistic filmcooled turbine blade. The code is used to study the combination of film and convection cooling. While most ofthe theoretical studies considered isothermal blade surfaces in thermal calculations over the blade surfaces. The results indicated that the film cooling enhances adiabatic effectiveness and decreases the surface heat flux by six times that of uncooling blade. In case of increasing the blowing ratios or streamwise injection angle, the adiabatic effectiveness decreases gradually. The effectiveness for combined cooling is higher than that of film cooling only due to the combination offilm and convection cooling together. Also the film cooling effectiveness for the VKI profile is higher than that ofthe C3X profile as a result ofthe better design shape of VKI profile. The model had been validated and tested with previously published experimental and theoretical results. These comparisons show a satisfactory agreement that permits an extension of the theoretical study. | ||||
| Keywords | ||||
| Film cooling; Effectiveness; Gas turbine; Nozzle blades | ||||
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