Towards High-Order Large Eddy Simulation of Aero-Thermal Flows for Turbomachinery Applications

Abstract

The solution accuracy and computational efficiency of high order Large Eddy Simulation (LES) solvers are evaluated on two benchmark open literature blade cascade problems. The first problem concerns wake development in the T106A low pressure turbine cascade [1]. The second problem examines the effect of free-stream turbulence on heat transfer from the VKI first stage high pressure turbine vane [2]. The calculations are performed with two independently developed high order LES solvers using completely different numerical algorithms. The first solver FDL3Di [3] was originally developed at the Airforce Research Laboratory (AFRL) and employs structured overset grids. It uses a sixth order compact finite difference scheme in space along with an implicit Beam-Warming scheme for time marching. The second solver, hpMusic, is developed at the University of Kansas [4]. This is a variable order (up to sixth order) unstructured grid solver employing a discontinuous formulation known as flux reconstruction (FR) / correction procedure via reconstruction (CPR) [5]. The computational grids used are independently tuned for each application. The solvers are benchmarked against experimental data for wake development and blade heat transfer coefficient. Further physical insights in to the test cases are also obtained, filling gaps in experimental results, especially for the VKI problem.

The Current State of High-Fidelity Simulations for Main Gas Path Turbomachinery Components and Their Industrial Impact

“…the kinetic loss values were not the same. Bhaskaran et al [5] also used different solvers with structured and unstructured grids and were the first to include the upstream bars for the inflow turbulence generation in a 6-th order accurate LES of the LS89 vane. The expected result was that heat transfer is controlled by the combination of turbulence intensity and length scale at the blade leading edge axial position, an information that is seldom available in the design phase, but that can have a large impact on performance.…”

“…additional non−linear terms (5) This relates the Reynolds stress tensor τ ij to its trace 2k, strain rate tensor S ij and additional non-dimensional terms. V k ij are basis functions formed from polynomials of non-dimensional strain s ij = τ S ij and rotation rate…”

Eddy Resolving Strategies in Turbomachinery and Peripheral Components

“…3. Note, the purple line shows the exciting potential of high-order methods and hence the re-emergence of interest in such approaches in many applications including turbomachinery [8][9][10][11][12]. Flow Classification.…”

On the mesh resolution of industrial LES based on the DNS of flow over the T106C turbine

“…Large eddy simulation [1] has received increased attention for industrial applications over the past decade for challenging vortex-dominated turbulent flows [2][3][4][5][6]. Direct numerical simulations have also been used to study interesting flow physics at low Reynolds numbers, e.g.…”

“…It has been shown that in some cases SGS models may be detrimental to the solution quality [33][34][35][36]. In practice, implicit LES (ILES) has proved its potential for turbulent flow simulations [4,5,[37][38][39]. In the context of LES, high-order adaptive methods such as DG and FR/CPR have been shown to resolve a wider spectrum than the classical FD method, and are comparable to the CD method in terms of resolution power [40,41].…”