Evaluation of Non-Cavitating Steady State Performance of an Aero-Engine Gear Pump by Numerical Methods

2017 ◽  
Author(s):  
Shivakumar Ulaganathan ◽  
Ch. Kanna Babu ◽  
Girish Kalyanrao Degaonkar
Keyword(s):  
Numerical Analysis ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Internal Flow ◽  
Operating Conditions ◽  
Gear Pump ◽  
Design Features ◽  
Flow Features ◽  
Gear Pumps ◽  
Aero Engines

External gear pumps are typically used in aero-engines for the fuel and lubrication system due to its simplicity in construction. The design of the gear pump has been considerably improved over several years by including design features to improve its overall performance and reliability. In this paper, three-dimensional numerical analysis of an external gear was carried out by including design features such as scallops at the inlet and outlet, radial and axial clearances, journal bearing clearances and the axial tilt of the supporting bushes. The Immersed Solid Method (ISM) is used to analyze the gear pump at different operating conditions. The applicability of different turbulence models to the Immersed solid method is discussed. The internal flow features are discussed and compared with the results available in the literature. The Pump characteristics curve developed from the numerical analysis using the Immersed solid method (ISM) is compared with the experimental test results.

scholarly journals Evaluation of Tooth Space Pressure and Incomplete Filling in External Gear Pumps by Means of Three-Dimensional CFD Simulations

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 342
Author(s):  
Alessandro Corvaglia ◽  
Massimo Rundo ◽  
Paolo Casoli ◽  
Antonio Lettini
Keyword(s):  
Three Dimensional ◽  
Operating Conditions ◽  
Dynamics Simulation ◽  
Inlet Pressure ◽  
Gear Pump ◽  
External Gear Pumps ◽  
Internal Fluid ◽  
Incomplete Filling ◽  
Gear Pumps ◽  
High Dynamics

The paper presents the computational fluid dynamics simulation of an external gear pump for fluid power applications. The aim of the study is to test the capability of the model to evaluate the pressure in a tooth space for the entire shaft revolution and the minimum inlet pressure for the complete filling. The model takes into account the internal fluid leakages and two different configurations of the thrust plates have been considered. The simulations in different operating conditions have been validated with proper high dynamics transducers measuring the internal pressure in a tooth space for the entire shaft revolution. Steady-state simulations have been also performed in order to detect the fall of the flow rate due to the incomplete filling of the tooth spaces when the inlet pressure is reduced. It has been demonstrated that, despite the need of a compromise for overcoming the limitation of considering fixed positions of the gears’ axes and of the thrust plates, significant results can be obtained, making the CFD approach very suitable for such analyses.

Numerical Analysis of the Deterministic Stresses Associated to Impeller-Tongue Interactions in a Single Volute Centrifugal Pump

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
J. M. Fernández Oro ◽  
J. González ◽  
R. Barrio Perotti ◽  
M. Galdo Vega
Keyword(s):  
Numerical Analysis ◽  
Numerical Model ◽  
Centrifugal Pump ◽  
Turbulence Intensity ◽  
Three Dimensional ◽  
Relevant Information ◽  
Three Dimensional Flow ◽  
Deterministic Analysis ◽  
Starting Point ◽  
Flow Features

In this paper, a deterministic stress decomposition is applied over the numerical three-dimensional flow solution available for a single volute centrifugal pump. The numerical model has proven in previous publications its robustness to obtain the impeller to volute-tongue flow interaction, and it is now used as starting point for the current research. The main objective has been oriented toward a detailed analysis of the lack of uniformity in the flow that the volute tongue promotes on the blade-to-blade axisymmetric pattern. Through this analysis, the fluctuation field may be retrieved and main interaction sources have been pinpointed. The results obtained with the deterministic analysis become of paramount interest to understand the different flow features found in a typical centrifugal pump as a function of the flow rate. Moreover, this postprocessing tool provides an economic and easy procedure for designers to compare the different deterministic terms, also giving relevant information on the unresolved turbulence intensity scales. Complementarily, a way to model the turbulent effects in a systematic way is also presented, comparing their impact on the performance with respect to deterministic sources in a useful framework, that may be applied for similar kinds of pumps.

Methodology for the Evaluation of Gear Pump Performance

2020 ◽  
Author(s):  
Logan T. Williams
Keyword(s):  
Empirical Data ◽  
Pressure Rise ◽  
Operating Conditions ◽  
Volumetric Efficiency ◽  
Fluid Viscosity ◽  
Gear Pump ◽  
Pump Performance ◽  
Pump Speed ◽  
Multiple Parameters ◽  
Gear Pumps

Abstract Currently, most performance curves of gear pumps present volumetric efficiency as a function of one or more operating conditions. However, the nature of gear pumps is that volumetric efficiency is dependent on pump speed, pump pressure rise, and fluid viscosity. This dependency on multiple parameters impedes direct comparisons between pumps tested at disparate operating conditions or on different testbeds. A new method has been developed that formulates the volumetric efficiency as a function of a single parameter that captures pump speed, pressure, and fluid viscosity. The characteristics of the pump is then captured by curve fitting two constants to empirical data. This method allows extrapolation of pump performance beyond empirical data and direct comparison of the volumetric efficiency curves of two pumps tested under disparate conditions within a single plot. This work describes the analytical derivation of the methodology and the empirical data used for validations. Additionally, several possible applications of this method are presented.

scholarly journals Darmstadt Rotor No. 2, II: Design of Leaning Rotor Blades

2003 ◽  
Vol 9 (6) ◽  
pp. 385-391
Author(s):  
Jörg Bergner ◽  
Dietmar K. Hennecke ◽  
Martin Hoeger ◽  
Karl Engel
Keyword(s):  
Mechanical Stability ◽  
Three Dimensional ◽  
Stability Limit ◽  
Operating Conditions ◽  
Rotor Blades ◽  
Navier Stokes ◽  
Structural Constraints ◽  
Transonic Compressor ◽  
Aero Engines ◽  
The Impact

For Darmstadt University of Technology's axial singlestage transonic compressor rig, a new three-dimensional aft-swept rotor was designed and manufactured at MTU Aero Engines in Munich, Germany. The application of carbon fiber–reinforced plastic made it possible to overcome structural constraints and therefore to further increase the amount of lean and sweep of the blade. The aim of the design was to improve the mechanical stability at operation that is close to stall.To avoid the hazard of rubbing at the blade tip, which is found especially at off-design operating conditions close to the stability limit of the compression system, aft-sweep was introduced together with excessive backward lean.This article reports an investigation of the impact of various amounts of lean on the aerodynamic behavior of the compressor stage on the basis of steady-state Navier-Stokes simulations. The results indicate that high backward lean promotes an undesirable redistribution of mass flow and gives rise to a basic change in the shock pattern, whereas a forward-leaning geometry results in the development of a highly back-swept shock front. However, the disadvantage is a decrease in shock strength and efficiency.

The calculation of gear pump porting areas by mathematical means

2014 ◽  
Vol 229 (1) ◽  
pp. 180-188 ◽  
Author(s):  
Martin K Yates
Keyword(s):  
Computer Aided Design ◽  
Gear Pump ◽  
Fuel Delivery ◽  
Lumped Parameter ◽  
Pinion Gear ◽  
Computer Aided ◽  
Gear Pumps ◽  
Aero Engines ◽  
Definition Of ◽  
Aided Design

Twin pinion gear pumps are used widely in industrial hydraulics and as fuel-delivery pumps for aero engines. The kinematics of the pumping action leads to high-flow rates into and out of the meshing gears, and at the high speeds used with aerospace fuel pumps cavitation can occur. One-dimensional ‘lumped parameter’ models are often used to analyse this type of pump. These methods rely on an accurate description of the volume trapped by the meshing teeth and the flow areas during the meshing cycle. Typically, multiple computer-aided design models have to be created to calculate these values during the meshing cycle. This paper presents a mathematical method for calculating these parameters based on a parametric definition of the gear and inlet and outlet porting. Green's theorem is used to allow line integrals around the periphery of the tooth spaces to be used to calculate the volumes and flow areas. Winding numbers are used to calculate the inflow and outflow areas that are formed by the intersection of the trapped volume and the side area porting. The method is validated against computer-aided design model data. This method is well suited for incorporation in an optimisation algorithm since the geometry is defined parametrically.

Toward Defining Objective Criteria for Assessing the Adequacy of Assumed Axisymmetry and Steadiness of Flows in Rotating Cavities

2005 ◽  
Vol 128 (4) ◽  
pp. 708-716 ◽  
Author(s):  
G. D. Snowsill ◽  
C. Young
Keyword(s):  
Boundary Conditions ◽  
A Priori ◽  
Three Dimensional ◽  
Cyclic Symmetry ◽  
Acceptable Solution ◽  
Inappropriate Use ◽  
Flow Features ◽  
Computational Fluid Dynamics Cfd ◽  
Aero Engines ◽  
Multiple Reference

The need to make a priori decisions about the level of approximation that can be accepted—and subsequently justified—in flows of industrial complexity is a perennial problem for computational fluid dynamics (CFD) analysts. This problem is particularly acute in the simulation of rotating cavity flows, where the stiffness of the equation set results in protracted convergence times, making any simplification extremely attractive. For example, it is common practice, in applications where the geometry and boundary conditions are axisymmetric, to assume that the flow solution will also be axisymmetric. It is known, however, that inappropriate imposition of this assumption can lead to significant errors. Similarly, where the geometry or boundary conditions exhibit cyclic symmetry, it is quite common for analysts to constrain the solutions to satisfy this symmetry through boundary condition definition. Examples of inappropriate use of these approximating assumptions are frequently encountered in rotating machinery applications, such as the ventilation of rotating cavities within aero-engines. Objective criteria are required to provide guidance regarding the level of approximation that is appropriate in such applications. In the present work, a study has been carried out into: (i) The extent to which local three-dimensional features influence solutions in a generally two-dimensional (2D) problem. Criteria are proposed to aid in decisions about when a 2D axisymmetric model is likely to deliver an acceptable solution; (ii) the influence of flow features which may have a cyclic symmetry that differs from the bounding geometry or imposed boundary conditions (or indeed have no cyclic symmetry); and (iii) the influence of unsteady flow features and the extent to which their effects can be represented by mixing plane or multiple reference frame approximations.

Fluidic Jet Barriers for Sealing Applications

2011 ◽  
Author(s):  
Simon I. Hogg ◽  
Isabel Gomez Ruiz
Keyword(s):  
New Technology ◽  
Internal Flow ◽  
Labyrinth Seal ◽  
Operating Conditions ◽  
Seal Design ◽  
Brush Seal ◽  
Fluid Jets ◽  
Flow Features ◽  
Upstream Direction ◽  
Physical Barriers

The turbine industry is continually looking for new developments to improve thermodynamic performance and sealing has received significant attention over the years. Fluidic seals employ aerodynamic flow features to create blockage/loss and reduce leakage, rather than relying on physical barriers to flow such as brush seal bristle packs etc. They are also potentially cheaper to implement than contacting seal technologies such as brush seals. The fundamental mechanism by which fluid jets inclined in an upstream direction produce blockage and reduce the flow along leakage channels are examined in the paper. Computational Fluid Dynamics is used to quantify the net gain in leakage performance that can be achieved in simple channel flow for various operating conditions and jet configurations. These results are used to guide further CFD calculations in which the potential for leakage reduction from adapting conventional labyrinth turbomachinery seal designs to include fluidic jets is investigated. Calculations are carried out for operating conditions that are typical of gas and steam turbine applications, in order to demonstrate the potential of new seal designs of this generic type. The device considered in the paper is essentially a conventional labyrinth seal design which is modified to include internal flow channels within the structure supporting the labyrinth fins, to supply the fluidic jets. The new technology is therefore a modification to an existing component with potential for application in existing turbine designs, requiring no/minimal changes outside of the seal design space to implement.

Research on Floating Moment Balancing Mechanism of a Gear Pump's Asymmetric Floating Plate with a V-Shaped Groove

2013 ◽  
Vol 415 ◽  
pp. 555-558
Author(s):  
An Lin Wang ◽  
Xiao Lu Zhang ◽  
Xue Wen Shan ◽  
Wei Liu
Keyword(s):  
Flow Field ◽  
Structural Characteristics ◽  
Evaluation Criteria ◽  
Internal Flow ◽  
Experimental Tests ◽  
Gear Pump ◽  
Balance Performance ◽  
Floating Plate ◽  
Gear Pumps ◽  
Groove Structure

Symmetrical floating plate of the high pressure and large displacement gear pump in rated conditions is inability to achieve the floating moment balance. To solve this problem, a new balancing mechanism is presented in this paper, which is asymmetric with a V-shaped groove structure on its driven side, called asymmetric balancing mechanism. Compared with traditional symmetric balancing mechanism, the floating plate with asymmetric balancing mechanism the can the coupling problem between the gear shaft and gear inner flow field through its own asymmetrical structure, so that the gear pumps internal flow field was the symmetrical distribution. According to the structural characteristics of the floating plates, Parameterized moment model based on discrete feature points was established. Theoretical analysis and experimental tests show the result , when suffered floating moment as evaluation criteria, in rated conditions, compared with the traditional symmetrical balancing mechanism one, that the balance performance of the floating plate with V-shaped groove asymmetric balancing mechanism improve by 41.42%.

scholarly journals Characterization of Model-Based Uncertainties in Incompressible Turbulent Flows by Machine Learning

2018 ◽  
Author(s):  
Mustafa Usta ◽  
Ali Tosyali
Keyword(s):  
Machine Learning ◽  
Turbulent Flows ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Machine Learning Algorithms ◽  
Mean Flow ◽  
Flow Properties ◽  
Significant Discrepancy ◽  
Model Based ◽  
Flow Features

This work determines the inaccuracy of using Reynolds averaged Navier Stokes (RANS) turbulence models in transition to turbulent flow regimes by predicting the model-based discrepancies between RANS and large eddy simulation (LES) models. Then, it incorporates the capabilities of machine learning algorithms to characterize the discrepancies which are defined as a function of mean flow properties of RANS simulations. First, three-dimensional CFD simulations using k-omega Shear Stress Transport (SST) and dynamic one-equation subgrid-scale models are conducted in a wall-bounded channel containing a cylinder for RANS and LES, respectively, to identify the turbulent kinetic energy discrepancy. Second, several flow features such as viscosity ratio, wall-distance based Reynolds number, and vortex stretching are calculated from the mean flow properties of RANS. Then the discrepancy is regressed on these flow features using the Random Forests regression algorithm. Finally, the discrepancy of the test flow is predicted using the trained algorithm. The results reveal that a significant discrepancy exists between RANS and LES simulations, and ML algorithm successfully predicts the increased model uncertainties caused by the employment of k-omega SST turbulence model for transitional fluid flows.

Comparison of Various RANS Models for Impinging Round Jet Cooling From a Cylinder

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Ketan Atulkumar Ganatra ◽  
Dushyant Singh
Keyword(s):  
Heat Transfer ◽  
Numerical Analysis ◽  
Turbulence Model ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Jet Impingement ◽  
Target Surface ◽  
Point Of View ◽  
Nozzle Diameter ◽  
Round Jet

The numerical analysis for the round jet impingement over a circular cylinder has been carried out. The v2f turbulence model is used for the numerical analysis and compared with the two equation turbulence models from the fluid flow and the heat transfer point of view. Further, the numerical results for the heat transfer with original and modified v2f turbulence model are compared with the experimental results. The nozzle is placed orthogonally to the target surface (heated cylindrical surface). The flow is assumed as the steady, incompressible, three-dimensional and turbulent. The spacing between the nozzle exit and the target surface ranges from 4 to 15 times the nozzle diameter. The Reynolds number based on the nozzle diameter ranges from 23,000 to 38,800. From the heat transfer results, the modified v2f turbulence model is better as compared to the other turbulence models. The modified v2f turbulence model has the least error for the numerical Nusselt number at the stagnation point and wall jet region.

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