CFD Analysis of Gear Windage Losses: Validation and Parametric Aerodynamic Studies

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Matthew J. Hill ◽  
Robert F. Kunz ◽  
Richard B. Medvitz ◽  
Robert F. Handschuh ◽  
Lyle N. Long ◽  
...  
Keyword(s):  
Experimental Data ◽  
Spur Gear ◽  
Mitigation Strategies ◽  
Test Facility ◽  
Cfd Analysis ◽  
Physical Mechanisms ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Cfd Analyses ◽  
Good Agreement

A computational fluid dynamics (CFD) method has been applied to gear configurations with and without shrouding. The goals of this work have been to validate the numerical and modeling approaches used for these applications and to develop physical understanding of the aerodynamics of gear windage loss. Several spur gear geometries are considered, for which experimental data are available. Various canonical shrouding configurations and free spinning (no shroud) cases are studied. Comparisons are made with experimental data from open literature, and data recently obtained in the NASA Glenn Research Center Gear Windage Test Facility, Cleveland, OH. The results show good agreement with the experiment. The parametric shroud configuration studies carried out in the Glenn experiments and the CFD analyses elucidate the physical mechanisms of windage losses as well as mitigation strategies due to shrouding and newly proposed tooth contour modifications.

Pumping Loss of Shrouded Meshed Spur Gears

2020 ◽  
Vol 142 (11) ◽  
Author(s):  
Michael J. Hurrell ◽  
Jerzy T. Sawicki
Keyword(s):  
High Speed ◽  
Spur Gear ◽  
Test Facility ◽  
Spur Gears ◽  
Cfd Analysis ◽  
Total Load ◽  
New Approach ◽  
Computational Fluid Dynamics Cfd ◽  
Loss Component ◽  
Swept Volume

Abstract High speed rotorcraft transmissions are subject to load-independent power losses consisting of drag loss and pumping loss. Tightly conforming shrouds enclosing the transmission gears are often incorporated to reduce the drag component of the total load-independent losses. However, tightly conforming axial shrouds can result in an increase in the pumping loss component. Quantifying the pumping loss of shrouded gear transmissions has been the subject of many studies. This study presents a new approach for estimating pumping loss based on the concept of swept volume and examines the applicability of the approach to various shroud configurations. The drag loss and pumping loss of a shrouded spur gear pair have been determined through testing using the NASA Glenn Research Center (GRC) Gear Windage Test Facility. The results from this testing have been compared to theoretical results using the formulations presented in this study. In addition, computational fluid dynamics (CFD) analysis has been conducted for the various shroud configurations tested at NASA GRC. The results from the CFD analysis confirm the theoretical and empirical results and provide insight into the applicability of the swept volume approach for estimating pumping power loss of shrouded gear transmissions.

Model Testing and CFD Analysis of 2D Profiles Towards Offshore Applications

2013 ◽  
Author(s):  
Lucas do Vale Machado ◽  
Antonio Carlos Fernandes ◽  
Gustavo César Rachid Bodstein
Keyword(s):  
Experimental Data ◽  
Experimental Measurements ◽  
Cfd Analysis ◽  
Two Dimensional ◽  
Reference Simulation ◽  
Sst Turbulence Model ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results ◽  
Naca 0015 ◽  
Good Agreement

In this paper we present numerical and experimental work motivated by the study of a rudder profile with significant levels of lift that provides better performance for the maneuvering and stabilization of a ship. This is the so-called Schilling profile. The analysis of the two-dimensional subsonic steady flow over four profiles was carried out using computational fluid dynamics (CFD) tools with a κ-ω SST turbulence model. We consider three Schilling profiles with different thicknesses and the classical NACA 0015 profile, taken as a reference. Simulation results were compared to our experimental measurements at various angles of attack and two orders of magnitude of the Reynolds number, 5.45 × 104 and 1.09 × 105. The numerical results show general good agreement with experimental data and highlight the distinct behavior of Schilling profile.

Multiphase CFD Analysis of a Subsea Intervention System

2015 ◽  
Author(s):  
Elham Maghsoudi ◽  
Uday Godse ◽  
Alistair Gill
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Large Scale ◽  
Cfd Analysis ◽  
Cfd Models ◽  
System A ◽  
Mixing Behavior ◽  
Computational Fluid Dynamics Cfd ◽  
2D And 3D ◽  
Good Agreement

In this study, a computational fluid dynamics (CFD) analysis was conducted to evaluate a new design of an intervention system. A multiphase analysis was performed to understand the mixing characteristics as the cement is pumped into the well and the degree to which the cement could be contaminated with spacer fluid. A transient multiphase analysis was conducted to examine the flow and the mixing behavior through the various sections of the intervention system. A combination of 2D and 3D CFD models was used, depending upon the geometry in each section. The results indicated that the intervention system operates efficiently without diluting the cement. Non-Newtonian methods used in CFD were validated using available theoretical and experimental data. In a large-scale yard test, good agreement was obtained for resin and water; however, cement did not show good agreement as the flow rate increased over 1 bbl/min.

Development of the DLE Combustor for L30A Gas Turbine

2015 ◽  
Author(s):  
Toshiaki Sakurazawa ◽  
Takeo Oda ◽  
Satoshi Takami ◽  
Atsushi Okuto ◽  
Yasuhiro Kinoshita
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Nox Emission ◽  
Test Facility ◽  
Exhaust Temperature ◽  
Main Burner ◽  
Harmful Emissions ◽  
Emission Regulation ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Analyses

This paper describes the development of the Dry Low Emission (DLE) combustor for L30A gas turbine. Kawasaki Heavy Industries, LTD (KHI) has been producing relatively small-size gas turbines (25kW to 30MW class). L30A gas turbine, which has a rated output of 30MW, achieved the thermal efficiency of more than 40%. Most continuous operation models use DLE combustion systems to reduce the harmful emissions and to meet the emission regulation or self-imposed restrictions. KHI’s DLE combustors consist of three burners, a diffusion pilot burner, a lean premix main burner, and supplemental burners. KHI’s proven DLE technologies are also adapted to the L30A combustor design. The development of L30 combustor is divided in four main steps. In the first step, Computational Fluid Dynamics (CFD) analyses were carried out to optimize the detail configuration of the combustor. In a second step, an experimental evaluation using single-can-combustor was conducted in-house intermediate-pressure test facility to evaluate the performances such as ignition, emissions, liner wall temperature, exhaust temperature distribution, and satisfactory results were obtained. In the third step, actual pressure and temperature rig tests were carried out at the Institute for Power Plant Technology, Steam and Gas Turbines (IKDG) of Aachen University, achieving NOx emission value of less than 15ppm (O2=15%). Finally, the L30A commercial validation engine was tested in an in-house test facility, NOx emission is achieved less than 15ppm (O2=15%) between 50% and 100% load operation point. L30A field validation engine have been operated from September 2012 at a chemical industries in Japan.

An anti-crystallization design of selective catalytic reduction nozzle holder

2021 ◽  
pp. 095440702097084
Author(s):  
Dewen Liu ◽  
Kai Lu ◽  
Shusen Liu ◽  
Yan Wu ◽  
Shuzhan Bai
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Injection System ◽  
Test Results ◽  
Verification Methods ◽  
Crystallization Risk ◽  
Protective Cover ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Good Agreement

From the aspect of reducing the risk of crystallization on nozzle surface, a new design of nozzle protective cover was to solve the problem in selective catalytic reduction (SCR) urea injection system. The simulation calculation and experimental verification methods were used to compare different schemes. The results show that reducing the height of nozzle holder can reduce the vortex currents near nozzle surface and effectively reduce the risk of crystallization on the nozzle surface. It is proposed to install a protective cover in the nozzle holder under the scheme of reducing the height of nozzle holder, which can further eliminate the vortex. Simulation and test results demonstrate good agreement under the rated running condition. The scheme of adding a protective cover in the nozzle holder shows the least crystallization risk by computational fluid dynamics (CFD) method. The crystallization cycle test shows that, after the height of nozzle holder is reduced, the risk of crystallization on the nozzle surface is reduced correspondingly. The addition of a protective cover in the nozzle holder solves the problem of crystallization on the nozzle surface, which provides a new method for anti-crystallization design.

The Hydrodynamics Studies on Loop Seal in CFBC Boiler Using CFD Analysis

2019 ◽  
Vol 15 (1) ◽  
Author(s):  
M. Vivekanandan ◽  
N. Anantharaman ◽  
M. Premalatha
Keyword(s):  
Pressure Drop ◽  
Circulating Fluidized Bed ◽  
Unit Length ◽  
Mechanical Valve ◽  
Sand Particle ◽  
Cfd Analysis ◽  
Solid Mass ◽  
Mass Fluxes ◽  
Computational Fluid Dynamics Cfd ◽  
Good Agreement

Abstract In a circulating fluidized bed (CFB), the loop seal is an important component which recirculates the solids captured by the cyclone to the bottom of the riser and avoids the direct flow of gas from high-pressure riser to the low-pressure cyclone. Most of the CFBC systems employ a Non-Mechanical valve, and its function has been investigated by many researchers. In this work, the flow of solid particle within the loop seal has been studied elaborately, and various design and operating parameters of the loop seal were analyzed in detail using Computational Fluid Dynamics (CFD). The CFD study has handled a loop-seal of dimension 110 mm × 430 mm × 400 mm high. This analysis has been done with a 200 µm sand particle and it is checked for its flow ability through various sizes and by altering the L/H ratio for three solid mass fluxes and for three L/H ratios of loop seal. The rate of solid mass flux depends on the length of the horizontal passage connecting the recycle cycle compartment of the loop seal with the supply chamber and hence the solid flow rate and the pressure difference per unit length are directly proportional to the length of the chamber or passage. Hence, L/H ratio is taken as a driving variable for the optimum performance of loop seal. The CFD analysis results reveal that the aeration of the solid to be used within the loop-seal should be higher than the Minimum Fluidization velocity. Also, keeping the length of the horizontal passage constant and varying the height of the passage will reduce the pressure drop. The pressure drop across the horizontal passage decreases up to a certain L/H ratio after which it increases. By comparing the three L/H ratios, L/H ratio of 2.62 is having a lesser pressure drop for the three mass fluxes. L/H ratio of 2.62 is having a good fluidization phenomenon and also the flow from the recycle chamber is more in comparison to the other L/H ratios. Experimental data from the literature is in good agreement with the CFD results.

scholarly journals ICCM2015: A Comparison of RANS and LES Computational Methods in Analyzing Ventilation Flow Through a Room Fitted with a Two-Sided Windcatcher

2017 ◽  
Vol 14 (03) ◽  
pp. 1750021 ◽  
Author(s):  
A. Niktash ◽  
B. P. Huynh
Keyword(s):  
Natural Ventilation ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Interior Space ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through ◽  
Cfd Method ◽  
Good Agreement

A windcatcher is a structure for providing natural ventilation using wind power; it is usually fitted on the roof of a building to exhaust the inside stale air to the outside and supplies the outside fresh air into the building interior space working by pressure difference between outside and inside of the building. In this paper, the behavior of free wind flow through a three-dimensional room fitted with a centered position two-canal bottom shape windcatcher model is investigated numerically, using a commercial computational fluid dynamics (CFD) software package and LES (Large Eddy Simulation) CFD method. The results have been compared with the obtained results for the same model but using RANS (Reynolds Averaged Navier–Stokes) CFD method. The model with its surrounded space has been considered in both method. It is found that the achieved results for the model from LES method are in good agreement with RANS method’s results for the same model.

Coupled CFD-ANN Procedure for Extending Heat Transfer Correlations Out of Their Range of Validity

2012 ◽  
Author(s):  
Andrea Viano ◽  
Gabriele Ottino ◽  
Luca Ratto ◽  
Giuseppe Spataro
Keyword(s):  
Neural Network ◽  
Heat Transfer ◽  
Experimental Data ◽  
Nusselt Number ◽  
Gas Turbine ◽  
Training Session ◽  
Nonlinear Problems ◽  
Artificial Neural ◽  
Cfd Analyses ◽  
Good Agreement

The heat transfer coefficient and pressure losses are among the main parameters to be evaluated in gas turbine cooling network design. Due to the complexity of these estimates, correlation-based computations are typically used as a result of time-consuming and expensive experimental activities. One of the main problems that the industry has to face is that these correlations, based on non-dimensional experimental data, produce reliable results in a range of validity typically different from that encountered in gas turbine applications. This paper will present preliminary results of an innovative procedure based on CFD analyses and Artificial Neural Networks, able to extend correlation predictions out of their range of validity, without any additional experimental data. Well-known test cases were replicated by building corresponding CAD geometries which were discretized by means of appropriate meshes, resulting from grid-independence studies. CFD analyses, based on the RANS approach, were performed to overlay the computations of the Nusselt number obtained from experimental activities. A preliminary comparison among turbulence models was carried out to find one leading to a good agreement with the experimental data. Then, an optimization method, based on Evolutionary Algorithms, was applied to the CFD analyses in order to find the best set of constant values for the chosen turbulence model, leading to the most accurate prediction of the experimental dataset. The resulting ad hoc CFD model was adopted in order to analyse test case configurations characterized by parameters within and external to the correlation validity field, building a sufficiently wide feeding database. A feed-forward multi-layer neural network was selected among network architectures typically used in engineering applications for prediction analyses. ANNs were chosen because they enable the solution of these complex nonlinear problems by using simple computational operations. The selected Artificial Neural Network was trained by a back-propagation procedure on the CFD results regarding Nusselt number. The validation of the resulting ANN was performed comparing its outputs with experimental data external to the correlation range of validity, which had not been used in the training session. Good agreement has been found. Results are presented and discussed.

Piston-Lift Check Valve Flow Verification Using CFD

2018 ◽  
Author(s):  
Matthew Laney ◽  
Ronald Farrell
Keyword(s):  
Flow Characteristics ◽  
Check Valve ◽  
Valve Lift ◽  
Cfd Analysis ◽  
Test Results ◽  
Finite Element Software ◽  
Translational Movement ◽  
Wide Range ◽  
Computational Fluid Dynamics Cfd ◽  
Good Agreement

Computational Fluid Dynamics (CFD) is increasingly being used as a reliable method for determining flow characteristics of a wide range of flow situations. This paper presents an extension of paper PVP2017-66269, “Check Valve Flow and Disk Lift Simulation Using CFD” [1], and utilizes some of the same concepts to characterize flow through piston-lift check valves. The previous example considered a swing check valve involving rotational movement; this example considers a vertical lift piston check valve involving translational movement. Specifically, CFD was used to determine valve flow coefficients (CV) as a function of disk lift position as well as to determine the flow rate required to achieve full open or predict intermediate disk lift positions. The CFX application, which is part of the ANSYS suite of finite element software, was used to determine the flow characteristics. As presented in PVP2017-66269, balancing flow-induced forces on the check element and considering the disk assembly weight, the valve lift behavior can be predicted. Results from the CFX analysis were compared to recent test results of a skirted disk-piston check valve and previous test results of a standard disk-piston check valve. The results showed good agreement in most cases. This validates that flow characteristics across valves with different types of check elements at different disk lift positions can be reliably predicted using CFD analysis. It is important to note that while the test results and CFD analysis showed good agreement, it was vital that actual testing be performed in order to validate the approach. This follows the recommendation outlined in the previous paper.

Pumping Loss of Shrouded Meshed Spur Gears

2020 ◽  
Author(s):  
Michael J. Hurrell ◽  
Jerzy T. Sawicki
Keyword(s):  
High Speed ◽  
Fluid Dynamic ◽  
Spur Gear ◽  
Test Facility ◽  
Spur Gears ◽  
Cfd Analysis ◽  
Total Load ◽  
New Approach ◽  
Loss Component ◽  
Swept Volume

Abstract High speed rotorcraft transmissions are subject to load-independent power losses consisting of drag loss and pumping loss. Tightly conforming shrouds enclosing the transmission gears are often incorporated to reduce the drag component of the total load-independent losses. However, tightly conforming axial shrouds can result in an increase in the pumping loss component. Quantifying the pumping loss of shrouded gear transmissions has been the subject of many studies. This study presents a new approach for estimating pumping loss based on the concept of swept volume and examines the applicability of the approach to various shroud configurations. The drag loss and pumping loss of a shrouded spur gear pair has been determined through testing using the NASA Glenn Research Center (GRC) Gear Windage Test Facility. The results from this testing have been compared to theoretical results using the formulations presented in this study. In addition, computational fluid dynamic (CFD) analysis has been conducted for the various shroud configurations tested at NASA GRC. The results from the CFD analysis confirm the theoretical and empirical results and provide insight into the applicability of the swept volume approach for estimating pumping power loss of shrouded gear transmissions.

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