The Importance of Shroud Leakage Modeling in Multistage Turbine Flow Calculations

Abstract

Three-dimensional steady multistage calculations, using the mixing plane approach, are compared with experimental measurement in a low-speed three-stage model turbine. The comparisons are made with two levels of shroud seal clearance, one representative of a real turbine and one with minimal seal clearance and almost no shroud leakage. Three different calculations are compared. The first computes the main blade path with no modeling of shroud leakage. The second includes a simple model of shroud leakage using sources and sinks on the end-walls, and the third is a multiblock calculation with all leakage paths and cavities computed. It is found that neglect of shroud leakage makes the computed velocity profiles and loss distributions significantly different to those measured. Simple modeling of shroud leakage gives some improvement but full calculation of the leakage flows and cavities is necessary to obtain good agreement between calculation and measurement.

Origins and Structure of Spike-Type Rotating Stall

“…Nomenclature c x ¼ axial chord p ¼ pressure p 01 ¼ rotor inlet stagnation pressure r t ¼ tip radius All the computations presented in this paper were performed using Turbostream [11]. The code is a structured multiblock RANS solver that was developed using the method employed in the Denton code, TBLOCK [23]. The approach is finite-volume time-marching, second order in space, with three levels of multigrid and a single step explicit time integration scheme.…”

Hot Streak and Vane Coolant Migration in a Downstream Rotor

“…A multi-block flow solver, TBLOCK [16] has been used for the numerical studies presented in this paper. The code is a finite volume, unsteady RANS solver, which uses the explicit Scree [17] scheme which is second order accurate in space.…”

“…Indeed, reliable predictions of flow structure and loss over a range of turbomachinery applications have been reported using this method (e.g. Rosic et al [16], Gabadebo et al [21]). …”

SBLOCK: A Framework for Efficient Stencil-Based PDE Solvers on Multi-core Platforms

“…The TBLOCK solver is widely used in both industry and in academia, and is the latest in a long line of previous codes by Denton that are known collectively as the "Denton codes". A complete description of the algorithm used by the solver is given by Klostermeier [11] while shorter overviews and examples of its application to turbomachinery research have been published by Reid et al [12] and Rosic et al [13]. In addition, the motivation for the current method can be traced through a series of papers by Denton [14][15] [16].…”

“…3). The benchmarks use a real turbomachinery simulation taken from Rosic et al [13]. In its baseline configuration, the case contains 72 blocks and four million grid nodes, but can be scaled up as required -the largest case for the weak scaling on 64 GPUs contains 160 million grid nodes and 2880 blocks.…”