Van Lookeren研究了拟流度比为0时的蒸汽驱前缘预测模型,提出形状因子取得最大值时的注汽参数为最优参数。而在实际油藏中,由于地层中原油黏度较大,或注汽速率较小,拟流度比往往较大,此时利用最大形状因子优化注汽参数受到限制。针对该...Van Lookeren研究了拟流度比为0时的蒸汽驱前缘预测模型,提出形状因子取得最大值时的注汽参数为最优参数。而在实际油藏中,由于地层中原油黏度较大,或注汽速率较小,拟流度比往往较大,此时利用最大形状因子优化注汽参数受到限制。针对该情形,应用数学方法研究了拟流度比不为0时的蒸汽驱前缘预测模型。绘制了形状因子、拟流度比、注汽速率与前缘形状关系图版,发现增大注汽速率,可增大形状因子,从而减小拟流度比,减轻蒸汽超覆程度,提高前缘驱的波及效率。由于注汽速率受注汽压力限制,研究了注汽速率与注汽压力的协调关系,利用该关系和研究的前缘模型,对前人的注汽参数优化方法进行了改进。展开更多
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）...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.展开更多
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-ESPOSApartially supported by the Long-term Framework Advancement Plan provided by Ministry of Industry and Trade of the Czech Republic
文摘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.
