A Comparison of Experimental and Numerical Studies Performed on a Low-Pressure Turbine Blade Cascade at High-Speed Conditions, Low Reynolds Numbers and Various Turbulence Intensities

作     者：Jan Michalek Petr Straka 

作者机构：VZLU - Aerospace Research and Test Establishment Beranovych 13019500 PragueCzech Republic 

出 版 物：《Journal of Thermal Science》 (热科学学报（英文版）)

年 卷 期：2013年第22卷第5期

页      面：413-423页

核心收录：

学科分类：082502[工学-航空宇航推进理论与工程] 08[工学] 0825[工学-航空宇航科学与技术] 

基　　金：funded by the European Commission within the FP7 project "Efficient Systems and Propulsion for Small Aircraft ESPOSA",grant agreement No.ACP1-GA-2011-284859-ESPOSA partially supported by the Long-term Framework Advancement Plan provided by Ministry of Industry and Trade of the Czech Republic 

主　　题：low pressure turbine high-speed flow low Reynolds number flow separation transition RANS 

摘      要：This paper focuses on a comparison of experimental and numerical investigations performed on a low-pressure mid-loaded turbine blade at operating conditions comprised of a wide range of Math numbers （from 0.5 - 1.1）, Reynolds numbers （from 0.4e＋5 - 3.0e＋5）, flow incidence （-15 - 15 degrees） and three levels of free-stream tur- bulence intensities （2, 5 and 10%）. The experimental part of the work was performed in a high-speed linear cas- cade wind tunnel. The increased levels of turbulence were achieved by a passive grid placed at the cascade inlet. A two-dimensional flow field at the center of the blade was traversed pitch-wise upstream and downstream the cascade by means of a five-bole probe and a needle pressure probe, respectively. The blade loading was measured using the surface pressure taps evenly deployed at the blade mid-span along the suction and the pressure side. The inlet turbulence was investigated using the constant temperature anemometer technique with a dual sensor probe. Experimentally evaluated values of turbulent kinetic energy and its dissipation rate were then used as inputs for the numerical simulations. An in-house code based on a system of the Favre-averaged Navier-Stokes equation closed by a two-equation k-co turbulence model was adopted for the predictions. The code utilizes an algebraic model of bypass transition valid both for attached as for separated flows taking in account the effect of free-stream turbulence and pressure gradient. The resulting comparison was carried out in terms of the kinetic en- ergy loss coefficient, distributions of downstream wakes and blade velocity. Additionally a flow visualization was performed by means of the Schlieren technique in order to provide a further understanding of the studied phe- nomena. A few selected cases with a particular interest in the attached and separated flow transition are compared and discussed.