RANS Analysis of HL-CRM at Take-off and Landing Configurations with different Flap Deflections and Engine Settings using DLR-TAU Code

This paper presents numerical optimization of a rotating rectangular channel design with the staggered arrays of pin-fins using Kriging meta-modeling technique. In the reference case, the channel aspect ratio (AR) is 4:1, the pin length to diameter ratio (H/D) is 2.0, and the pin spacing to diameter ratio is 2.0 in both the streamwise and spanwise directions. The rotation number is 0.15, while the Reynolds number based on hydraulic diameter is fixed at 10,000. Rotation of the channel slightly reduces the heat transfer on the leading surface and increases it on the trailing surface due to Coriolis effects. Two non-dimensional variables, the ratio of the height to diameter of the pin-fin and the ratio of the spacing between the pin-fins to diameter of the pin-fins, are chosen as design variables. The objective function defined as a linear combination of heat transfer and friction loss related terms with a weighting factor is selected for the optimization. Twenty training points generated by Latin hypercube sampling (LHS) are evaluated by three-dimensional Reynolds-averaged Navier-Stokes (RANS) analysis with the shear stress transport (SST) model for the turbulence closure. The predictions of objective function by Kriging meta-modeling at optimum point show reasonable accuracy in comparison with the values calculated by RANS analysis. The results of optimization show that the cooling performance of the optimized shape is enhanced significantly through the optimization.

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RANS Analysis of An Iced Airfoil at Medium/High Reynolds Number

25th AIAA Applied Aerodynamics Conference ◽

10.2514/6.2007-4283 ◽

2007 ◽

Cited By ~ 1

Author(s):

Claudio Maria Marongiu ◽

Pier Luigi Vitagliano ◽

Giorgio Zanazzi ◽

Robert Narducci

Keyword(s):

Reynolds Number ◽

High Reynolds Number ◽

High Reynolds ◽

Rans Analysis

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CFD–RANS analysis of the rotational effects on the boundary layer of wind turbine blades

Journal of Physics Conference Series ◽

10.1088/1742-6596/75/1/012031 ◽

2007 ◽

Vol 75 ◽

pp. 012031 ◽

Cited By ~ 5

Author(s):

Carlo E Carcangiu ◽

Jens N Sørensen ◽

Francesco Cambuli ◽

Natalino Mandas

Keyword(s):

Boundary Layer ◽

Wind Turbine ◽

Turbine Blades ◽

Wind Turbine Blades ◽

Rans Analysis

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Optimization of Printed Circuit Heat Exchanger Using Exergy Analysis

Journal of Heat Transfer ◽

10.1115/1.4029849 ◽

2015 ◽

Vol 137 (6) ◽

Cited By ~ 9

Author(s):

Sang-Moon Lee ◽

Kwang-Yong Kim

Keyword(s):

Heat Exchanger ◽

Objective Function ◽

Exergy Analysis ◽

Navier Stokes ◽

Printed Circuit ◽

Flow Channels ◽

Design Variables ◽

Modeling Techniques ◽

Geometric Variables ◽

Rans Analysis

A printed circuit heat exchanger (PCHE) with zigzag flow channels in a double-faced configuration was optimized to enhance its thermal–hydraulic performance. Using exergy analysis, the objective function was defined as the net exergy gain of the system considering the exergy gain by heat transfer and exergy loss due to friction in the channels. A Reynolds-averaged Navier–Stokes (RANS) analysis and surrogate modeling techniques were used for the optimization. Three geometric variables were selected as the design variables. The objective function was calculated at each design point through RANS analysis in order to construct a response surface surrogate model. Through the optimization, both the thermal and hydraulic performances of the PCHE were improved with respect to the reference geometry by suppressing flow separation in the channels.

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Understanding of Secondary Loss Structures in a Multi-Stage Transonic Compressor Using DES

Volume 2D: Turbomachinery ◽

10.1115/gt2016-57218 ◽

2016 ◽

Author(s):

Donghyun Kim ◽

Changmin Son ◽

Kuisoon Kim

Keyword(s):

Flow Separation ◽

Pressure Loss ◽

Total Pressure ◽

Three Dimensional ◽

Total Pressure Loss ◽

Suction Surface ◽

Corner Region ◽

Transonic Compressor ◽

Multi Stage ◽

Rans Analysis

In the present study, a multi-stage transonic compressor has been analyzed to investigate secondary loss structures and flow interactions in the corner region where the hub endwall and blade suction surface meet. The Detached Eddy Simulation (DES) approach is used successfully with the Shear Stress Transport (SST) turbulence model to directly resolve the eddy structure in the separated region. The SST-DES results for a transonic three stage axial compressor are compared with a RANS analysis obtained using ANSYS CFX. The present analysis indicates that the DES is better in simulating secondary losses and vortex structures than the RANS. With the DES, a large three-dimensional separation is predicted in the stator suction surface and hub endwall compared to the RANS prediction. The flow separation affects adversely the loss characteristics such as increases in the entropy and total pressure loss. The DES analysis indicates that the secondary flow phenomenon of the stator rows is apparent in all stages. It is observed to predict two distinct vortices induced by a three dimensional flow separation in the region adjacent to the suction surface and trailing edge of the last stage stator near the hub endwall. For the front two stages, the DES also predicts strong vortices and flow separation in the same corner region while the RANS analysis fails to predict them clearly. The total pressure loss prediction is concerned, the DES analysis predicts significantly larger than the RANS analysis in the region where the hub corner separation occurs. The DES is also found to predict a periodic fluctuations in the entropy, leading to the instantaneous efficiency variations with maximum differences of about 10% compared with the RANS solutions.

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Unsteady Effects of Blade Row Interaction on Flow Field and Aerodynamic Performance of a Transonic Centrifugal Compressor Impeller

10.1115/gt2021-59462 ◽

2021 ◽

Author(s):

Kazutoyo Yamada ◽

Kosuke Kubo ◽

Kenichiro Iwakiri ◽

Yoshihiro Ishikawa ◽

Hirotaka Higashimori

Keyword(s):

Steady State ◽

Flow Field ◽

Centrifugal Compressor ◽

Aerodynamic Performance ◽

Vaned Diffuser ◽

Tip Leakage ◽

Transonic Centrifugal Compressor ◽

Compressor Performance ◽

Unsteady Effects ◽

Rans Analysis

Abstract This paper discusses the unsteady effects associated with the impeller/diffuser interaction on the internal flow field and aerodynamic performance of a centrifugal compressor. In centrifugal compressors with a vaned diffuser, the flow field is inherently unsteady due to the influence of interaction between the impeller and the diffuser, and the unsteadiness of the flow field can often have a great influence on the aerodynamic performance of the compressor. Especially in high-load compressors, it is considered that large unsteady effects are produced on the compressor performance with a strong flow unsteadiness. The unsteady effect on aerodynamic performance of the compressor has not been fully revealed yet, and sometimes the steady-state RANS simulation finds it difficult to predict the compressor performance. In this study, numerical simulations have been conducted for a transonic centrifugal compressor with a vaned diffuser. The unsteady effects were clarified by comparing the numerical results between a single-passage steady-state RANS analysis and a full-annulus unsteady RANS analysis. The comparison of simulation results showed the difference in entropy generation in the impeller. The impingement of diffuser shock wave with the impeller pressure surface brought about a cyclic increase in the blade loading near the impeller trailing edge. Accordingly, with increasing tip leakage flow rate, a second tip leakage vortex was newly generated in the aft part of the impeller, which resulted in additional unsteady loss generation inside the impeller.

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