CUED Publications database

A critical examination of a correlation-based transition model for low pressure turbines

Lefas, D and Cui, J and Tucker, PG (2017) A critical examination of a correlation-based transition model for low pressure turbines. In: UNSPECIFIED.

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Two of the main requirements identified for a fully compatible CFD transition model demand that: first it does not affect the underlying turbulence model in fully turbulent regimes and second, that it is applicable to three dimensional flows. The purpose of this paper is to determine whether the γ - Re model satisfies these requirements for Low Pressure Turbines (LPTs). The γ - Re model’s performance for LPTs is positive overall. A significant improvement on the underlying SST model is observed. The total pressure loss coefficient (Y ) predicted at the exit plane by the γ - Re model is only 4% greater than that determined by quasi-DNS, compared to 16% greater for the SST model. In the midspan region, the γ - Re model successfully predicts a laminar boundary layer on the suction surface. This laminar boundary layer separates near the trailing edge and then reattaches after transition, resulting in a fully turbulent boundary layer downstream. The location of separation and subsequent separation-induced transition from the γ - Re model agrees almost in full with the quasi-DNS results. However, a number of significant limitations are identified, especially in the endwall region. First, γ close to the endwall tends towards zero in the γ - Re model, resulting in a zero production of turbulent kinetic energy. Second, even though the laminar region close to the pressure surface is readily identified up to z = 14.3, for the higher z-planes examined this is not the case. This contradicts the quasi-DNS results. Finally, the production of turbulence along the suction surface by the corner vortex is significantly underestimated by the γ - Re model. θ θ p θ θ θ θ θ +

Item Type: Conference or Workshop Item (UNSPECIFIED)
Divisions: Div A > Fluid Mechanics
Div A > Turbomachinery
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 19:26
Last Modified: 10 Apr 2021 00:49
DOI: 10.2514/6.2017-0782