ABSTRACT
With the development of low cost computing power, computational fluid dynamics (CFD) technologies for turbomachinery flow have progressed significantly [1–7]. Three-dimensional steady flow calculations based on the Reynolds averaged Navier-Stokes equations are now relatively well established and routinely used to optimize blading and flow path contours. At the present time, numerical methods do not always predict the absolute aerodynamic loss exactly because of the inadequate physical models. However, the variations of aerodynamic performance due to design changes are predicted adequately for engineering guidance. CFD applications for investigating different design options are very useful during the design cycle. However, further studies are being conducted to improve the accuracy of numerical solutions so that the error in the calculated aerodynamic loss can be maintained below a certain margin. For this purpose, several test flows in turbomachinery have been proposed to evaluate the current capability of various CFD codes to calculate the aerodynamic loss in representative turbomachinery flows. For the turbine flow field, a well documented set of measurements in a low speed linear turbine cascade at Durham University, England, has been used as one of the test flows by ERCOFTAC [8]. The numerical exercises at the well organized ERCOFTAC meetings 224have indicated that the measured loss structure in this rather simple turbine blade row has not been successfully calculated so far. Working Group 26 of AGARD has used a well documented subsonic turbine flow measurement obtained at DLR [9]. Again, various calculations indicate that the detailed loss distributions are not well calculated. The primary objective of the current study is to evaluate the current capability of a turbomachinery CFD code in terms of calculating aerodynamic loss with two sets of well documented turbine flow. The calculations were executed without any specific tuning of any parameters inside the code. The numerical results are compared with the measurements as well as with previously published numerical results.
