Large eddy simulation of free-stream turbulence effects on heat transfer to a high-pressure turbine cascade

2010 ◽  
Vol 11 ◽  
pp. N6 ◽  
Author(s):  
Rathakrishnan Bhaskaran ◽  
Sanjiva K. Lele
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Large Eddy Simulation ◽  
Free Stream ◽  
Turbine Cascade ◽  
High Pressure Turbine ◽  
Free Stream Turbulence ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Turbulence Effects

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

2017 ◽  
Author(s):  
R. Bhaskaran ◽  
Feilin Jia ◽  
Gregory M. Laskowski ◽  
Z. J. Wang ◽  
Umesh Paliath
Keyword(s):  
Heat Transfer ◽  
Large Eddy Simulation ◽  
Numerical Algorithms ◽  
High Order ◽  
Sixth Order ◽  
Computational Grids ◽  
Variable Order ◽  
Free Stream Turbulence ◽  
Eddy Simulation ◽  
Large Eddy

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.

Large Eddy Simulation of Combustor and Complete Single-Stage High-Pressure Turbine of the FACTOR Test Rig

2019 ◽  
Author(s):  
Martin Thomas ◽  
Jerome Dombard ◽  
Florent Duchaine ◽  
Laurent Gicquel ◽  
Charlie Koupper
Keyword(s):  
High Pressure ◽  
Large Eddy Simulation ◽  
Combustion Chamber ◽  
Measurement Data ◽  
Single Stage ◽  
High Pressure Turbine ◽  
Lean Burn ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Compact Design

Abstract Development goals for next generation aircraft engines are mainly determined by the need to reduce fuel consumption and environmental impact. To reduce NOx emissions lean combustion technologies will be applied in future development projects. The more compact design and the absence of dilution holes in this type of engines shortens residence times in the combustion chamber and reduces mixing which results in higher levels of swirl, turbulence and temperature distortions at the exit of the combustion chamber. For these engines interactions between components are more important, so that the traditional engine design approach of component-wise optimization will have to be adapted. To study new lean burn architectures the European FACTOR project investigates the transport of hot streaks produced by a non-reactive combustor simulator through a single stage high-pressure turbine. In this work high-fidelity Large Eddy Simulation (LES) of combustor and complete high-pressure turbine are discussed and validated against experimental data. Measurement data is available on P40 (exit of the combustion chamber), P41 (exit of the stator) and P42 (exit of the rotor) and generally shows a good agreement to LES data.

Numerical Simulations of the Near-Field Region of Film Cooling Jets Under High Free Stream Turbulence: Application of RANS and Hybrid URANS/Large Eddy Simulation Models

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Hosein Foroutan ◽  
Savas Yavuzkurt
Keyword(s):  
Experimental Data ◽  
Large Eddy Simulation ◽  
Film Cooling ◽  
Free Stream ◽  
Near Field ◽  
Turbulent Heat ◽  
Field Region ◽  
Free Stream Turbulence ◽  
Eddy Simulation ◽  
Large Eddy

This paper investigates the flow field and thermal characteristics in the near-field region of film cooling jets through numerical simulations using Reynolds-averaged Navier–Stokes (RANS) and hybrid unsteady RANS (URANS)/large eddy simulation (LES) models. Detailed simulations of flow and thermal fields of a single-row of film cooling cylindrical holes with 30 deg inline injection on a flat plate are obtained for low (M = 0.5) and high (M = 1.5) blowing ratios under high free stream turbulence (FST) (10%). The realizable k‐ε model is used within the RANS framework and a realizable k‐ε-based detached eddy simulation (DES) is used as a hybrid URANS/LES model. Both models are used together with the two-layer zonal model for near-wall simulations. Steady and time-averaged unsteady film cooling effectiveness obtained using these models are compared with available experimental data. It is shown that hybrid URANS/LES models (DES in the present paper) predict more mixing both in the wall-normal and spanwise directions compared to RANS models, while unsteady asymmetric vortical structures of the flow can also be captured. The turbulent heat flux components predicted by the DES model are higher than those obtained by the RANS simulations, resulting in enhanced turbulent heat transfer between the jet and mainstream, and consequently better predictions of the effectiveness. Nevertheless, there still exist some discrepancies between numerical results and experimental data. Furthermore, the unsteady physics of jet and crossflow interactions and the jet lift-off under high FST is studied using the present DES results.

scholarly journals Loss Prediction in an Axial Compressor Cascade at Off-Design Incidences With Free Stream Disturbances Using Large Eddy Simulation

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
John Leggett ◽  
Stephan Priebe ◽  
Aamir Shabbir ◽  
Vittorio Michelassi ◽  
Richard Sandberg ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Free Stream ◽  
Axial Compressor ◽  
Operating Conditions ◽  
Boundary Layer Transition ◽  
Compressor Cascade ◽  
Free Stream Turbulence ◽  
Eddy Simulation ◽  
Profile Losses ◽  
Large Eddy

Axial compressors may be operated under off-design incidences due to variable operating conditions. Therefore, a successful design requires accurate performance and stability limits predictions under a wide operating range. Designers generally rely both on correlations and on Reynolds-averaged Navier–Stokes (RANS), the accuracy of the latter often being questioned. The present study investigates profile losses in an axial compressor linear cascade using both RANS and wall-resolved large eddy simulation (LES), and compares with measurements. The analysis concentrates on “loss buckets,” local separation bubbles and boundary layer transition with high levels of free stream turbulence, as encountered in real compressor environment without and with periodic incoming wakes. The work extends the previous research with the intention of furthering our understanding of prediction tools and improving our quantification of the physical processes involved in loss generation. The results show that while RANS predicts overall profile losses with good accuracy, the relative importance of the different loss mechanisms does not match with LES, especially at off-design conditions. This implies that a RANS-based optimization of a compressor profile under a wide incidence range may require a thorough LES verification at off-design incidence.

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