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.
Evaluation of buckling load and dynamic performance of steel shear wall retrofitted with strips made of shape memory alloy
One of the most imperfections of the steel shear wall is out of plane displacements that cause severe damage in both structural and non-structural elements. In this paper, the effects of shape-memory alloys on steel shear walls are investigated. First, a numerical analysis using the finite element method in ABAQUS software has been carried out according to an experimental test. The results of the numerical analysis have been verified with experimental results. Next, shape-memory alloy fibers have been added vertically and horizontally to various parts of the steel shear wall. The results show that retrofitting with the shape-memory alloy reduces the out-of-plane displacement of the steel shear wall under both cyclic and seismic loadings. Besides, the buckling load in the steel shear wall increases when it is retrofitted with the shape-memory alloy. Also, the total out-of-plane movement (accumulated absolute displacements) of the steel shear wall and non-structural damage are controlled by the characteristic of a shape-memory alloy material called “super-elastic”.