CALCULATION OF FLOW CHARACTERISTICS IN HEAT TURBOMACHINERY TURBINE STAGE WITH DIFFERENT THREE DIMENSIONAL SHAPE OF THE STATOR BLADE WITH ANSYS CFX SOFTWARE
Main purpose of the presented work was the investigation of influence of three dimensional blades over flow characteristics. The paper presents comparison between experimental and CFD (Computational Fluid Dynamics) data so called verification test, impulse turbine stage with Frozen Rotor and Transient Rotor Interface modeling. Static pressure distribution was measured at mid span of the blade. The paper discusses secondary flow phenomena.
Validation of Numerical Computations and Turbulence Models Combinations for Gas Turbine Cascade Blade Flow
The accuracy of computer codes for turbo-machinery turbulent flow field calculations relies strongly on the type and behavior of the turbulence model used in the computations. Analysis of different Reynolds Average Navier-Stokes Equation (RANS) based turbulence models was applied to predict the flow field in the linear first stage gas turbine cascade blade. The experimental investigation is also introduced to validate the accuracy of turbulence models. This was done by using five linear cascade blades tested in an open jet type low-speed subsonic wind tunnel. The static pressure distribution was measured at the midspan of cascade middle blade by using static pressure taps. The numerical results obtained from different turbulence model simulations is individually reviewed for the correctness of its predictions and compared with the experimental data in terms of integrated flow parameters, such as static pressure coefficient distribution on both blade sides. The results show that RNG k-e turbulence model gave the best prediction of pressure distribution when compared with the experimental data. Prediction of standard k-e and k-ω turbulence models fail to predict accurately the flow field parameters in cascade passage. Prediction of (k-e) turbulence model overestimate the turbulence kinetic energy values, especially in the regions of high velocity at blade suction side, also not accurately predict the flow separation on the blade suction side.
The Off-Design Performance of a Low Pressure Turbine Cascade
The ability of a given blade profile to operate over a wide range of conditions is often of the utmost importance. This paper reports the off-design performance of a low pressure turbine rotor root section in a linear cascade. Data were obtained using pneumatic probes and surface flow visualisation. The effects of incidence (+9, 0, −20 deg.), Reynolds No. (1.5, 2.9, 6.0×105), pitch-chord ratio (0.46, 0.56, 0.69) and inlet boundary layer thickness (0.011, 0.022 δ*/C) are discussed. Particular attention is paid to the three-dimensionality of the flow field. Significant differences in the detail of the flow occur over the range of operating conditions investigated. It is found that the production of new secondary loss is greatest at the lower Reynolds numbers, positive incidence and the higher pitch-chord ratios.Copyright © 1986 by ASME