scholarly journals Aeroacoustic Analysis of the Tonal Noise of a Large-Scale Radial Blower

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Aurélien Marsan ◽  
Stéphane Moreau
Keyword(s):  
Numerical Simulations ◽  
Large Scale ◽  
Navier Stokes ◽  
Noise Generation ◽  
Tonal Noise ◽  
Radiated Noise ◽  
Rotating Blades ◽  
Reynolds Averaged Navier Stokes ◽  
Generation Mechanisms ◽  
Made In

Large-scale radial blowers are widely used in factories and are one of the main sources of noise. The present study aims at identifying the noise generation mechanisms in such a radial blower in order to suggest simple modifications that could be made in order to reduce the noise. The flow in a representative large-scale radial blower is investigated thanks to unsteady Reynolds-averaged Navier–Stokes (URANS) numerical simulations. The radiated noise is calculated, thanks to an in-house propagation code based on the Ffowcs Williams Hawkings' (FWH) analogy, SherFWH. The results highlight the main noise generation mechanisms, in particular the interaction between the rotating blades and the tongue, and the interaction between the rotating blades and the trapdoors located on the volute sidewall. Some modifications of the geometry are suggested.

Advanced Numerical Methods for the Prediction of Tonal Noise in Turbomachinery—Part I: Implicit Runge–Kutta Schemes

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Graham Ashcroft ◽  
Christian Frey ◽  
Kathrin Heitkamp ◽  
Christian Weckmüller
Keyword(s):  
Stokes Equations ◽  
Temporal Integration ◽  
Aerodynamic Noise ◽  
Navier Stokes ◽  
Noise Generation ◽  
Academic Problems ◽  
Tonal Noise ◽  
Navier Stokes Equations ◽  
Runge Kutta ◽  
The Stability

This is the first part of a series of two papers on unsteady computational fluid dynamics (CFD) methods for the numerical simulation of aerodynamic noise generation and propagation. In this part, the stability, accuracy, and efficiency of implicit Runge–Kutta schemes for the temporal integration of the compressible Navier–Stokes equations are investigated in the context of a CFD code for turbomachinery applications. Using two model academic problems, the properties of two explicit first stage, singly diagonally implicit Runge–Kutta (ESDIRK) schemes of second- and third-order accuracy are quantified and compared with more conventional second-order multistep methods. Finally, to assess the ESDIRK schemes in the context of an industrially relevant configuration, the schemes are applied to predict the tonal noise generation and transmission in a modern high bypass ratio fan stage and comparisons with the corresponding experimental data are provided.

Unsteady Simulations of Flow Field and Scalar Mixing in Transverse Jets

2009 ◽  
Author(s):  
Elizaveta Ivanova ◽  
Massimiliano Di Domenico ◽  
Berthold Noll ◽  
Manfred Aigner
Keyword(s):  
Large Scale ◽  
Quantitative Prediction ◽  
Navier Stokes ◽  
Scalar Mixing ◽  
Combustion Chambers ◽  
Mixing Processes ◽  
Transverse Jets ◽  
Vortical Structures ◽  
Jet In Crossflow ◽  
Reynolds Averaged Navier Stokes

This paper presents numerical simulations of flow and scalar mixing in two different jet in crossflow configurations. The testcases are chosen to resemble the dilution mixing processes in gas turbine combustion chambers. Unsteady simulations employing two different computational approaches are presented: unsteady Reynolds-Averaged Navier-Stokes (URANS) and Scale-Adaptive Simulations (SAS). The results obtained by each method are compared, analyzed, and validated against experimental data. The importance of the reproduction of the large-scale unsteady coherent vortical structures in the numerical simulation is demonstrated. Both URANS and SAS revealed the typical jet in crossflow vortical structures. The SAS method was able to resolve smaller structures than URANS on the same computational grid. The quantitative prediction accuracy of time-averaged velocities and temperatures is satisfactory for both methods. In contrast, the steady-state Reynolds-Averaged Navier-Stokes (RANS) computations failed for the present testcases.

Tonal noise generation mechanisms in low-speed mixed-flow fans

2014 ◽  
Author(s):  
Timothy J. Newman ◽  
Anurag Agarwal ◽  
Ann Dowling ◽  
Ryan Stimpson
Keyword(s):  
Noise Generation ◽  
Tonal Noise ◽  
Mixed Flow ◽  
Low Speed ◽  
Generation Mechanisms

Partially Averaged Navier-Stokes Turbulence Modeling of Flow in 5x5 PWR Fuel Assembly With Spacer Grid

2018 ◽  
Author(s):  
Giacomo Busco ◽  
Yassin A. Hassan
Keyword(s):  
Large Eddy Simulation ◽  
Numerical Simulations ◽  
Stokes Equations ◽  
Direct Numerical Simulations ◽  
Navier Stokes ◽  
Spacer Grid ◽  
Navier Stokes Equations ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Reynolds Averaged Navier Stokes

The highly turbulent flow inside a pressurized water reactor makes unpractical the use of scale resolving simulations, due to the large number of space and time turbulent structures. The high computational cost associated with typical large eddies simulations or direct numerical simulations techniques is unsuitable due to the large spatiotemporal resolution required. Partially averaged Navier-Stokes turbulence model is presented as bridging model between Reynolds averaged Navier-Stokes equations and direct numerical simulations. As filtered representation of the Navier-Stokes equations, the model is able to continuously shift its energy-based filter, inside the turbulence spectrum, being able to resolve the turbulent scales of interest. The choice of energy based cut-off filters gives the chance to directly impose the degree of needed resolution, where the most important large scales unsteadiness are resolved at minimal computational expenses. The partially averaged Navier-Stokes modelling approach has been tested for a Reynolds number of 14,000, inside a 5 × 5 fuel bundle, with a single spacer grid and split-type mixing vanes. Four different filters have been tested, whose resolution ranged from Reynolds averaged Navier-Stokes and large eddy simulation. A comparison with large eddy simulation will be presented. The results show that the partially averaged Navier-Stokes modeling produces results comparable to those of large eddy simulation when the appropriate cut-off energy filter is chosen. The turbulence models results will be compared with the available particle image velocimetry experimental data.

Assessment of the validity of RANS knock prediction using the resonance theory

2019 ◽  
Vol 21 (4) ◽  
pp. 610-621 ◽  
Author(s):  
Corinna Netzer ◽  
Lars Seidel ◽  
Frédéric Ravet ◽  
Fabian Mauss
Keyword(s):  
Numerical Simulations ◽  
Direct Numerical Simulations ◽  
Large Eddy Simulations ◽  
Navier Stokes ◽  
Post Processing ◽  
Resonance Theory ◽  
Auto Ignition ◽  
Engine Knock ◽  
Large Eddy ◽  
Reynolds Averaged Navier Stokes

Following the resonance theory by Bradley and co-workers, engine knock is a consequence of an auto-ignition in the developing detonation regime. Their detonation diagram was developed using direct numerical simulations and was applied in the literature to engine knock assessment using large eddy simulations. In this work, it is analyzed if the detonation diagram can be applied for post-processing and evaluation of predicted auto-ignitions in Reynolds-averaged Navier–Stokes simulations even though the Reynolds-averaged Navier–Stokes approach cannot resolve the fine structures resolved in direct numerical simulations and large eddy simulations that lead to the prediction of a developing detonation. For this purpose, an engine operating point at the knock limit spark advance is simulated using Reynolds-averaged Navier–Stokes and large eddy simulations. The combustion is predicted using the G-equation and the well-stirred reactor model in the unburnt gases based on a detailed gasoline surrogate reaction scheme. All the predicted ignition kernels are evaluated using the resonance theory in a post-processing step. According to the different turbulence models, the predicted pressure rise rates and gradients differ. However, the predicted ignition kernel sizes and imposed gas velocities by the auto-ignition event are similar, which suggests that the auto-ignitions predicted by Reynolds-averaged Navier–Stokes simulations can be given a meaningful interpretation within the detonation diagram.

Shock Waves and Plume Prediction of a Rocket Thruster With an Attached Panel

2003 ◽  
Author(s):  
Farhad Davoudzadeh ◽  
Nan-Suey Liu
Keyword(s):  
Supersonic Flow ◽  
Shock Waves ◽  
Flow Field ◽  
Numerical Simulations ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Experimental Measurements ◽  
Pressure Distributions ◽  
Temperature And Pressure ◽  
Reynolds Averaged Navier Stokes

Reynolds-Averaged Navier-stokes (RANS) numerical simulations are performed to predict the supersonic flow field induced by a H2-O2 rocket thruster with an attached panel, under a variety of operating conditions. The simulations have captured physical details of the flow field, such as the plume formation and expansion, formation of a system of shock waves and their effects on the temperature and pressure distributions on the walls. Comparison between the computed results for 2-D and adiabatic walls and the related experimental measurements for 3-D and cooled walls shows that the results of the simulations are consistent with those obtained from the related rig tests.

Virtual Gas Turbine: Pre-Processing and Numerical Simulations

2016 ◽  
Author(s):  
Feng Wang ◽  
Mauro Carnevale ◽  
Gan Lu ◽  
Luca di Mare ◽  
Davendu Kulkarni
Keyword(s):  
Computational Model ◽  
Numerical Simulations ◽  
Gas Turbine ◽  
Design Process ◽  
Large Scale ◽  
Physical Phenomenon ◽  
Navier Stokes ◽  
Time Cost ◽  
Turbine Engine ◽  
Geometrical Shapes

The design process of a gas turbine engine involves interrelated multi-disciplinary and multi-fidelity designs of engine components. Traditional component-based design process is not always able to capture the complicated physical phenomenon caused by component interactions. It is likely that such interactions are not resolved until hardware is built and tests are conducted. Component interactions can be captured by assembling all these components into one computational model. Nowadays, numerical solvers are fairly easy to use and the most time-consuming (in terms of man-hours) step for large scale gas turbine simulations is the preprocessing process. In this paper, a method is proposed to reduce its time-cost and make large scale gas turbine numerical simulations affordable in the design process. The method is based on a novel featured-based in-house geometry database. It allows the meshing modules to not only extract geometrical shapes of a computational model and additional attributes attached to the geometrical shapes as well, such as rotational frames, boundary types, materials, etc. This will considerably reduce the time-cost in setting up the boundary conditions for the models in a correct and consistent manner. Furthermore, since all the geometrical modules access to the same geometrical database, geometrical consistency is satisfied implicitly. This will remove the time-consuming process of checking possible mismatching in geometrical models when many components are present. The capability of the proposed method is demonstrated by meshing the whole gas path of a modern three-shaft engine and the Reynold’s Averaged Navier-Stokes (RANS) simulation of the whole gas path.

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