Boundary Layer Effects on the Transonic Flow in a Straight Turbine Cascade

Abstract

The analysis presented here deals with two subjects related to the transonic flow in a straight turbine cascade: 1) turbulization of the suction side boundary layer and its subsequent development along the profile 2) influence of side wall boundary layers on cascade flows. The turbulization effect of supersonic compression on the boundary layers which accompany transonic expansion on the suction side of the profile is investigated by independent methods. Both the experimental results and the calculation confirm the loss of stability of the laminar boundary layer and its subsequent transition into turbulence in the region of an adverse pressure gradient. Also the possibility of reverse transition of turbulent boundary layer in a subsequent strong favourable pressure gradient is investigated. The contraction effect of the wind tunnel side wall boundary layers is expressed by means of the AVDR factor over a wide range of flow regimes determined by the incidence angle and the Mach number. A correction of the exit flow angle from the cascade is made to obtain a purely 2D flow although it is apparent that the measured exit angle values and the exit angle obtained for a 2D flow differ considerably.

Flux schemes based finite volume method for internal transonic flow with condensation

“…The VFFC scheme yields very good results on both structured quadrilateral and unstructured triangular grids in the case of transonic inviscid flow of air in Geselschaft für Angewandte Mathematik und Mechanik (GAMM) channel that was already presented in [18]. It also delivers numerical results qualitatively comparable to other commonly used modern schemes [19] in the case of transonic inviscid flow of air ( = 1.4) in 2D turbine cascade SE1050, for cascade data see [20]. The examples of numerical results and comparison with experimental data for the flow case with the inlet total pressure 10 5 Pa, the inlet total temperature 273.15 K, the inlet flow angle 19.3 • , and the outlet mean pressure 42 322 Pa are given in Figure 3 (the secondorder method was used with MinMod limiter).…”

“…We consider an inviscid flow model, homogeneous nucleation, convection of droplets by vapor, and small values of liquid mass fraction (wetness). Under these assumptionsŠťastný andŠejna created a flow model [1], which consists of equations describing conservation of mass momentum and energy for the mixture, and further transport equations for wetness and Hills moments. The modification of this model is employed here.…”

Investigation of Compressible Flow Through a Turbine Blade Cascade for Various Transonic Flow Regimes

“…The optical and pressure measurements were carried out in a wide range of boundary conditions starting with the design operation up to the off-design operations with extensive separation, see Šťastný and Šafařík [3,4]. Optical measurements were carried out by the Mach-Zehnder interferometer and pressure measurements by the Prandtl probe upstream the blade cascade and by the five-hole conical probe in the traversing plane behind the blade cascade.…”

“…The typical turbine rotor blade cascade SE1050 has been investigated at various flow conditions in a wide range of Mach numbers and incidence angles including high positive and negative values (Šťastný and Šafařík [3,4]). Data related to the design operation are included as a test case in the ERCOFTAC Database CFD-QNET, see Příhoda and Kozel [5].…”

Generalization of an Analytical Two-Phase Steam Flow Calculator to High-Pressure Cases

“…Following single-phase measuring techniques, stagnation probes are often used in two phase flow situation (Petr,[2]; Stastny, [3]; White, [4]). In practice if the size of liquid droplets is small (less than one micron) the momentum (inertia) equilibrium between the two phase is maintained, and with the thermal equilibrium between the phases the pitot tube would measure the equilibrium stagnation pressure (Guha,[5]).…”