LES/DNS of flow past T106 LPT cascade using a higher-order LB model

TL;DR

This study evaluates a higher-order Entropic Lattice Boltzmann Method (ELBM) for simulating separated and transitional flows over a T106 Low-Pressure Turbine cascade without turbulence models, showing good agreement with experimental data.

Contribution

The paper demonstrates the effectiveness of a higher-order ELBM in capturing flow transition and separation in turbine cascades without explicit turbulence modeling.

Findings

Pressure coefficient matches experimental results.

Flow transition occurs under inlet disturbance.

Flow features agree with previous computational studies.

Abstract

The main objective of the present work is to assess higher-order Entropic Lattice Boltzmann Method (ELBM) for separated and transitional flows without the use of any explicit turbulence model. For this, we chose to simulate two cases of T106 Low-Pressure Turbine (LPT) cascade -- T106A and T106C -- representing incompressible and compressible flow regimes respectively. These results are obtained using our company's in-house higher-order ELBM transonic solver. We have carried out two sets of simulations for both the test cases. One with a clean inlet and the other with an inlet disturbance given by white Gaussian noise superimposed on the inlet velocity. For the clean inlet case, the flow remains laminar on the entire blade surface for both the test cases. It undergoes transition on the suction side for the inlet disturbance case. The pressure coefficient for the T106A and the isentropic Mach number on the blade surface for the T106C matches well with the experimental results. Also, the qualitative comparison of flow features in terms of the Q-criterion is in good agreement with the earlier computational results reported in literature.