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Simulation of flow through the tip-section turbine blade cascade for various inlet conditions
Straka, P. ; Příhoda, Jaromír
The contribution deals with the numerical simulation of 2D compressible flow through a tip-section of the turbine blade cascade using the EARSM turbulence model completed by the algebraic transition model. Predictions were carried out at the Reynolds number Re2is = 1.85E+06 for Mach numbers M2is = 1.77 and 1.92. The study was focused on the effect of small changes of flow inlet angle and changes of free-stream turbulence on flow structure in the blade cascade, especially on the shock wave/boundary layer interaction.
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Numerical Simulation of Compressible Transitional Flow Through High-Loaded Turbine Blade Cascade
Straka, P. ; Příhoda, Jaromír
The contribution deals with the numerical simulation of compressible transitional flow through the high-loaded turbine blade cascade. The mathematical model is based on the solution of the averaged Navier-Stokes equations closed by the explicit algebraic Reynolds stress model completed by the algebraic transition model taking into account the effect of free-stream turbulence and pressure gradient. The transition model is based on empirical correlations for the onset and the length of the transition region covering a wide range of free-stream turbulence. Various boundary conditions with the transition in attached and separated flows were tested and compared with experimental data.
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Modelling of the boundary-layer transition in the low-pressure turbine blade cascade
Straka, P. ; Příhoda, Jaromír
The paper deals with the application of a algebraic model of the bypass transition in attached and separated flow. The model was applied for flow in a low-pressure turbine blade cascade, where the flow field is strongly influenced by the transition in the separated flow. The aim is to points out some shortcomings of the current transition model and its modifications are proposed. Presented results of modelling are compared with the experimental data.
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Numerical solution of compressible flow through a turbine cascade using various transition models
Nádvorník, M. ; Straka, P. ; Příhoda, Jaromír
The contribution deals with the numerical simulation of 2D compressible flow through a linear turbine blade cascade. Simulations were carried out by the in-house numerical code based on the two-equation k-omega turbulence model with the algebraic transition model and by the commercial software Fluent using the three-equation turbulence model including the transition model proposed by Walters and Cokljat. Predictions carried out for different Reynolds and Mach numbers cover the transition in the attached and separated flow as well. Predicted values of the loss coefficient and the flow outlet angle were compared with experimental data for the turbine cascade VS33.
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Numerical modelling of the laminar/turbulent transition in the separated boundary layer on an airfoil
Ďuriš, M. ; Příhoda, Jaromír ; Maršík, František
The work deals with the numerical modelling of the laminar/turbulent transition in the separated boundary layer in 2D compressible flow. The prediction is based on the solution of the averaged Navier-Stokes equations closed by the k-omega turbulence model and by the algebraic model of the bypass transition. Calculations were carried out by the commercial software ANSYS FLUENT 6.3.26 complemented by the user defined functions. The proposed model is compared with experimental data obtained for flow over airfoils NACA 63A421 and XIS40MOD and various angles of the attack.
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Transition modelling in blade cascades
Straka, P. ; Příhoda, Jaromír
A modified algebraic model of the laminar/turbulent bypass transition was implemented into the in-house numerical code for the simulation of 2D compressible turbulent flow using the RANS equations closed by the two-equation k-omega TNT turbulence model. The model was verified by the ERCOFTAC test cases for various boundary-layer flows and applied for the simulation of the transitional flow in turbine blade cascades.
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Modification of an algebraic bypass-transition model for internal flows
Straka, P. ; Příhoda, Jaromír
The contribution deals with testing of an algebraic bypass-transition model for shear flows characteristic for turbomachinery. The transition model based on the algebraic equation for the intermittency coefficient is added to the averaged Navier-Stokes equations with the SST turbulence model. The transition onset and length are given by empirical relations. The modified model considers different intermittency coefficient in the transitional boundary layer and in the outer turbulent stream. The model was verified by means of test cases ERCOFTAC covering boundary-layer flow with various free-stream turbulence and pressure gradient.
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