Investigations on CFD Simulations for Predicting Windage Power Losses in Spur Gears

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Y. Marchesse ◽  
C. Changenet ◽  
F. Ville ◽  
P. Velex
Keyword(s):  
Three Dimensional ◽  
Volumetric Flow Rate ◽  
Spur Gears ◽  
Power Losses ◽  
Test Rig ◽  
Cfd Simulations ◽  
Specific Test ◽  
Computational Fluid Dynamics Cfd ◽  
Volume Method ◽  
Three Dimensional Simulations

In this paper, a computational fluid dynamics (CFD) code is applied to two- and three-dimensional simulations of windage power loss generated by spur gears rotating in air. Emphasis is placed on the various meshes associated with the finite volume method and on the choice of turbulence model. Comparing CFD predictions with the power losses measured on a specific test rig, it is shown that the fluid ejection in the radial direction must be included in order to reproduce the experimental evidence. The relative importance of the losses generated by the gear front and rear faces along with those due to the teeth is discussed. The volumetric flow rate expelled by the teeth is analyzed and the influence of flanges is highlighted.

On the Influence of a Hubside Exducer Cavity and Bleed Air in a Close-Coupled Centrifugal Compressor Stage

2017 ◽  
Vol 139 (7) ◽  
Author(s):  
Peter Kaluza ◽  
Christian Landgraf ◽  
Philipp Schwarz ◽  
Peter Jeschke ◽  
Caitlin Smythe
Keyword(s):  
Centrifugal Compressor ◽  
Pressure Field ◽  
State Of The Art ◽  
Test Rig ◽  
Cfd Simulations ◽  
Trailing Edge ◽  
Loss Mechanism ◽  
Aero Engine ◽  
Computational Fluid Dynamics Cfd ◽  
Stage Efficiency

In aero-engine applications, centrifugal compressors are often close-coupled with their respective diffusers to increase efficiency at the expense of a reduced operating range. The aim of this paper is to show that state-of-the art steady-state computational fluid dynamics (CFD) simulations can model a hubside cavity between an impeller and a close-coupled diffuser and to enhance the understanding of how the cavity affects performance. The investigated cavity is located at the impeller trailing edge, and bleed air is extracted through it. Due to geometrical limitations, the mixing plane is located in the cavity region. Therefore, the previous analyses used only a cut (“simple”) model of the cavity. With the new, “full” cavity model, the region inside the cavity right after the impeller trailing edge is not neglected anymore. The numerical setup is validated using the experimental data gathered on a state-of-the art centrifugal compressor test-rig. For the total pressure field in front of the diffuser throat, a clear improvement is achieved. The results presented reveal a drop in stage efficiency by 0.5%-points caused by a new loss mechanism at the impeller trailing edge. On the hubside, the fundamentally different interaction of the cavity with the coreflow increases the losses in the downstream components resulting in the mentioned stage efficiency drop. Finally, varying bleed air extraction is investigated with both cavity models. Only the full cavity (FC) model captures the changes measured in the experiment.

Transient CFD Visualization of Fossil Fuel Combustion Simulations

2003 ◽  
Author(s):  
Brian Dotson ◽  
Kent Eshenberg ◽  
Chris Guenther ◽  
Thomas O’Brien
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Cfd Simulation ◽  
Low Cost ◽  
Three Dimensional ◽  
Cfd Simulations ◽  
Projection System ◽  
Computational Fluid Dynamics Cfd ◽  
High Level ◽  
Wall System

The design of high-efficiency lower-emission coal-fed power plants is facilitated by the extensive use of computational fluid dynamics (CFD) simulations. This paper describes work conducted at the National Energy Technology Laboratory (NETL) and Pittsburgh Supercomputing Center (PSC) to provide an environment for the immersive three-dimensional visualization of CFD simulation results. A low-cost high-resolution projection system has been developed in the visualization lab at NETL. This multi-wall system consists of four projection screens, three of which are tiled into four quadrants. The graphics for the multi-wall system are rendered using a cluster of eight personal computers. A high-level visualization interface named Mavis has also been developed to combine the powerful 3D modules of OpenDX with methods developed at NETL for studying multiphase CFD data. With Python, a completely new OpenDX user interface was built that extends and simplifies the features of a basic graphics library.

scholarly journals A Comparative Study on the Performance of a Horizontal Axis Ocean Current Turbine Considering Deflector and Operating Depths

2020 ◽  
Vol 12 (8) ◽  
pp. 3333
Author(s):  
Nauman Riyaz Maldar ◽  
Cheng Yee Ng ◽  
Lee Woen Ean ◽  
Elif Oguz ◽  
Ahmad Fitriadhy ◽  
...  
Keyword(s):  
Fluid Pressure ◽  
Three Dimensional ◽  
Horizontal Axis ◽  
Ocean Current ◽  
Power Coefficient ◽  
Cfd Simulations ◽  
Torque Coefficient ◽  
Computational Fluid Dynamics Cfd ◽  
Turbine Design ◽  
Current Turbine

Several different designs and prototypes of ocean current turbines have been tested over recent years. For every design test, emphasis is given to achieving an optimum power output from the flow. In this study, the performance of a Horizontal Axis Ocean Current Turbine (HAOCT) has been investigated using three-dimensional Computational Fluid Dynamics (CFD) simulations for three cases, namely, (1) a turbine without a deflector, (2) a turbine with a deflector, and (3) a turbine with a deflector operating at a higher fluid depth. The turbine design was modeled in DesignModeler software and simulations were carried out in commercial CFD software Flow-3D. The Torque Coefficient (Cm) and Power Coefficient (Cp) for the turbine have been investigated for a certain range of Tip-Speed Ratios (TSRs) in a flow velocity of 0.7 m/s. Furthermore, comparisons have been made to demonstrate the effect of the deflector on the performance of the turbine and the influence of a higher fluid pressure on the same. The results from the simulations indicate that the higher value of Cp was achieved for Case 2 as compared to the other two cases. The findings from the study indicate that the use of the deflector enhances the performance of the turbine. Furthermore, a higher fluid pressure acting on the turbine has a significant effect on its performance.

Simulation of Spray Cooling in a Desublimer

2000 ◽  
Author(s):  
Malcolm J. Andrews ◽  
David Zwick
Keyword(s):  
Drop Size ◽  
Three Dimensional ◽  
Spray Cooling ◽  
Cfd Modeling ◽  
Lagrangian Description ◽  
Water Spray ◽  
Cfd Simulations ◽  
Computational Fluid Dynamics Cfd ◽  
Fully Coupled ◽  
Water Spray Cooling

Abstract Three-dimensional Computational Fluid Dynamics (CFD) simulations are presented for water spray cooling of a Phthalic Anhydride desublimer. The multiphase CFD modeling includes a fully coupled Eulerian/Lagrangian formulation for the carrier gas and water spray, and a quasi-steady model for the desublimation process. The use of a Lagrangian description for the spray enables a drop size distribution, but also necessitates running the simulation through the transient to obtain a steady operation result. The simulation has been used to study effect of drop size, spray dispersion and spray location/orientation.

Extent, capacity and possibilities of computational fluid dynamics as a design tool for pump intakes: a review

2018 ◽  
Vol 18 (5) ◽  
pp. 1518-1530 ◽  
Author(s):  
Jie Zhang ◽  
Tien Yee
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Three Dimensional ◽  
Design Tool ◽  
Cfd Modeling ◽  
Cfd Simulations ◽  
Pump Station ◽  
Computational Fluid Dynamics Cfd ◽  
Future Direction ◽  
Computational Resources

Abstract Flow near pump intakes is three-dimensional in nature, and is affected by many factors such as the geometry of the intake bay, uniformity of approach flow, critical submergence, placements and operation combinations of pumps and so on. In the last three decades, advancement of numerical techniques coupled with the increase in computational resources made it possible to conduct computational fluid dynamics (CFD) simulations on pump intakes. This article reviews different aspects involved in CFD modeling of pump station intakes, outlines the challenges faced by current CFD modelers, and provides an attempt to forecast future direction of CFD modeling of pump intakes.

Three-Dimensional Numerical Simulation of Fluid with Sparse Particles' Erosion to Pipelines

2013 ◽  
Vol 805-806 ◽  
pp. 1785-1789
Author(s):  
Chang Bin Wang ◽  
Miao Wang ◽  
Xiao Xu Li ◽  
Yu Liu ◽  
Jie Nan Dong
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Flow Model ◽  
Particle Distribution ◽  
Three Dimensional ◽  
Two Phase ◽  
Wear Area ◽  
Computational Fluid Dynamics Cfd ◽  
Set Up ◽  
Volume Method

A three dimensional fluid flow model was set up in this paper, based on the computational fluid dynamics (CFD) and the elasticity theory. Using the finite volume method, a 120° bend was taken as a research object to simulate the erosion to the wall of fluid with sparse particles, finally, to determine the most severe wear areas.At the same time, the distribution of two-phase flows pressure and velocity was analyzed in 45° and 90° bends, then tracked the trajectory of the particles. The results show that the 90°bend has the smallest wear area and particle distribution or combination property is the best.

scholarly journals Experimental investigations and analysis on churning losses of splash lubricated spiral bevel gears

2017 ◽  
Vol 18 (4) ◽  
pp. 412 ◽  
Author(s):  
S. Laruelle ◽  
C. Fossier ◽  
C. Changenet ◽  
F. Ville ◽  
S. Koechlin
Keyword(s):  
Experimental Tests ◽  
Operating Conditions ◽  
Experimental Investigations ◽  
Spiral Bevel Gear ◽  
Power Losses ◽  
Test Rig ◽  
Specific Test ◽  
Spiral Bevel Gears ◽  
Bevel Gears ◽  
Spiral Bevel

Churning losses are a complex phenomenon which generates significant power losses when considering splash lubrication of gear units. However, only few works deal with bevel gears dipped lubrication losses. The objective of this study is to provide a wide variety of experimental tests on churning losses, especially getting interested in geometry of spiral bevel gears influence. A specific test rig was used in order to study a single spiral bevel gear partially immersed in an oil bath. Experiments have been conducted for several operating conditions in terms of speeds, lubricants, temperatures and gear geometries to study their impact on splash lubrication power losses. These experimental results are compared with the predictions from various literature sources. As the results did not agree well with the predictions for all operating conditions, an extended equation derived from previous works is introduced to estimate churning losses of bevel gears.

A Hybrid Particle-Continuum Framework

2008 ◽  
Author(s):  
Matthew K. Borg ◽  
Jason M. Reese
Keyword(s):  
Three Dimensional ◽  
Computational Modelling ◽  
Numerical Code ◽  
Test Cases ◽  
Cfd Simulations ◽  
Hybrid Particle ◽  
Hybrid Framework ◽  
Computational Fluid Dynamics Cfd ◽  
Polyhedral Cells ◽  
The Individual

A new hybrid particle-continuum numerical code is currently being developed as an engineering tool for accurate and fast computational modelling of nanoflows. Molecular Dynamics (MD) and Computational Fluid Dynamics (CFD) are the components/solvers used within the particle and continuum zones respectively. In this paper the development of a two-component hybrid framework, based on domain-decomposition, is described. The main objective of the framework is to facilitate hybrid MD-CFD simulations within complex geometries, using a mesh of structured/unstructured arbitrary polyhedral cells, identical to that used in engineering CFD. This requires complex three-dimensional (3D) interfaces and overlap regions (comprising user-defined sub-regions) to be constructed between adjacent zones. The individual sub-regions serve as an appropriate means of exchanging information between components (i.e. coupling or boundary condition imposition), in 3D, during the hybrid simulation. The global domain is decomposed appropriately into MD and CFD sub-domains such that internal boundaries within the overlap regions become the external boundaries on the separate meshes, prior to commencing the hybrid simulations. The hybrid framework is implemented in OpenFOAM [1], an open source C++ CFD toolbox, using a general, case-independent approach and is parallelised. Two nanochannel test cases are investigated to show that the hybrid environment is flexible and well-suited for engineering design applications as well for the development of new hybrid codes and coupling models.

Effect of Combustion Chamber Geometry on Emissions From a Single-Cylinder Diesel Engine

2005 ◽  
Author(s):  
Boggavarapu V. V. S. U. Prasad ◽  
R. V. Ravikrishna
Keyword(s):  
Diesel Engine ◽  
Combustion Chamber ◽  
Direct Injection ◽  
Three Dimensional ◽  
Cfd Simulations ◽  
Government Regulations ◽  
Single Cylinder ◽  
Piston Bowl ◽  
Computational Fluid Dynamics Cfd ◽  
Valve Part

Many of the stationary power generation and agricultural pumping applications in India utilize diesel engines. Recently, as per Government regulations, these engines are required to satisfy stringent emissions norms. This forms the motivation for the present study on a stationary, direct-injection, single cylinder, 10 HP diesel engine. The selected engine was not satisfying the norms. The engine has a hemi- spherical piston bowl and an injector with a finite sac volume. The combustion chamber was made re-entrant and the injector was replaced with a sac-less injector. After these modifications, there is a significant change in emission levels. To understand clearly the effect of the combustion chamber geometry on the emission levels, three-dimensional computational fluid dynamics (CFD) simulations have been performed for the complete suction and closed-valve part of the cycle. Comparisons of turbulent kinetic energy and swirl levels of old and new geometries were systematically conducted. In contrary to the expected, that the swirl and turbulence levels are consistently less in the modified geometry than that of original geometry. A third combustion chamber was proposed and tested computationally. It was found that the in the proposed combustion chamber swirl and turbulence levels are much higher than the baseline engine. Thus, the proposed combustion chamber geometry shows significant potential for the engine to meet the prescribed norms.

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