Numerical Modeling of a Helical External Gear Pump With Continuous-Contact Gear Profile: A Comparison Between a Lumped-Parameter and a 3D CFD Approach of Simulation

2018 ◽  
Author(s):  
Xinran Zhao ◽  
Andrea Vacca ◽  
Sujan Dhar
Keyword(s):  
Cfd Simulation ◽  
Good Description ◽  
Helical Gear ◽  
Lumped Parameter Model ◽  
Fluid Power ◽  
Gear Pump ◽  
Continuous Contact ◽  
Positive Displacement ◽  
Lumped Parameter ◽  
Flow Features

The concept of continuous-contact helical gear pumps (CCHGP) has been proposed and successfully commercialized in the recent past. Thanks to the continuous-contact rotor profile design and to the helical gear structure, this design eliminates the kinematic flow oscillation. This has important implications on the fluid borne noise generation, which is considered as one of the major sources of noise emissions and mechanical vibrations for positive displacement machines. Although the commercial success of the CCHGP concept, there is very little published studies about the underling physics at the basis of the functioning of this type of design. This is mostly due to the complexity of the fluid domain that characterize the functioning of CCHGP units. In this paper, a transient 3D CFD study is conducted for a reference CCHGP unit for high-pressure (up to 200 bar) fluid power applications. The results of the 3D CFD simulation are compared with those given by a lumped-parameter model developed at the Maha Fluid Power Research Center of Purdue University (USA), which was previously validated against experimental results. The results show how with a proper discretization of the fluid domain the CFD simulation approach can be used for the case of helical CCHGP units. Both models provide a good description of the main features of operation of the unit. The lumped parameter model is quicker, thus suitable for fast optimization studies. However, the CFD results not only can be used to support the main assumptions done on the lumped parameter model, they also permit to gain further insight on the operation of the CCHGP unit, particularly with respect to the flow features of the meshing process.

scholarly journals Engineering Procedure for Positive Displacement Pump Performance Analysis Based on 1D and 3D CFD Commercial Codes

2017 ◽  
Author(s):  
Aleksandar Josifovic ◽  
Matthew Stickland ◽  
Aldo Iannetti ◽  
Jonathan Corney
Keyword(s):  
Cfd Simulation ◽  
Numerical Data ◽  
Experimental Tests ◽  
Input Function ◽  
Lumped Parameter Model ◽  
Cfd Analysis ◽  
Positive Displacement ◽  
Lumped Parameter ◽  
Time Required ◽  
Parameter Approach

A numerical analysis methodology, which demonstrates how a 1D pipework simulation can be enhanced with the results of a 3D CFD simulation of key components, is used to estimate the performance of multi-cylinder Positive Displacement pumps. The procedure uses of a 1-D lumped fluid dynamics model whose accuracy was improved by incorporating CFD analysis of the PD pump valves. The application describes how valve loss co-efficient resulting from CFD analysis was utilised by the lumped parameter model as an input function. The results suggest that the combination of the CFD and lumped parameter approach exceeds the limitations found by Iannetti [1] in modelling the interaction between the pump chambers of a multi-cylinder pump as the simplified lumped parameter approach makes the entire multi-cylinder model affordable in terms of computational power and time required. The results obtained are validated by means of experimental tests the results of which are presented together with the numerical data. An example of the capability of the procedure developed and the support it is able to provide to designers is also presented.

scholarly journals Lumped parameter model of vane pumps developed in OpenModelica environment

2021 ◽  
Vol 312 ◽  
pp. 05005
Author(s):  
Barbara Zardin ◽  
Giovanni Cillo ◽  
Marco Rizzoli ◽  
Massimo Borghi
Keyword(s):  
Flow Rate ◽  
Dynamic Behaviour ◽  
Fluid Dynamic ◽  
Dynamic Modelling ◽  
Physical Modelling ◽  
Lumped Parameter Model ◽  
Fluid Power ◽  
Vane Pump ◽  
Positive Displacement ◽  
Lumped Parameter

In this paper, the authors present a 0D fluid dynamic model of a vane pump used to refill tanks with fuel. The model is entirely developed in OpenModelica environment, where the authors have created specific libraries of elements suitable for the physical modelling of fluid power components and systems. Among the different approaches, the zero-dimension (0D) fluid-dynamic modelling of positive displacement machines is suitable to study many aspects as: the instantaneous flow rate, pressure and torque transients, the fluid borne noise related to the flow rate and pressure irregularity, the dynamic behaviour of the variable displacement control. Overall, this approach in modelling allows to link the geometrical features of the machine with its dynamic behaviour and for this reason is particularly useful in guiding the design. The model of the vane pump is described together with the main design features that can be analysed in terms of their influence on the pump behaviour. Besides the specific results obtained regarding the design of the pump, the paper also demonstrates the use of OpenModelica language and environment, and its efficacy, into the applications of fluid power modelling and simulation.

A New Continuous Contact Low-Noise Gear Pump

1983 ◽  
Vol 105 (4) ◽  
pp. 736-741 ◽  
Author(s):  
K. Mitome ◽  
K. Seki
Keyword(s):  
Point Contact ◽  
Practical Method ◽  
Spur Gear ◽  
Helical Gear ◽  
Low Noise ◽  
Tooth Profile ◽  
Gear Pump ◽  
Excellent Performance ◽  
Continuous Contact ◽  
Gear Pumps

Developed is a new low-noise gear pump which has no trapping and whose gears are in continuous one-point contact in the plane of rotation. First this paper studies a practical method to design the tooth profile of a spur gear for a given path of contact. A new tooth profile is obtained by giving a closed path of contact like a figure 8. Basic dimensions are determined and limites of them are obtained. Both theoretical and approximate displacements are expressed in terms of the basic dimensions. Secondly, a helical gear pump is studied. The helical gear can be discussed in the same way as the spur gear by new basic dimensions. Finally some test gear pumps are made and tested. Test prove that this gear pump has excellent performance and durability.

scholarly journals Multiphase CFD Simulation of Solid Propellant Combustion in a Small Gun Chamber

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Ahmed Bougamra ◽  
Huilin Lu
Keyword(s):  
Cfd Simulation ◽  
Numerical Study ◽  
Lumped Parameter Model ◽  
Charge Weight ◽  
Maximum Pressure ◽  
Multiphase Model ◽  
Velocity Increase ◽  
Muzzle Velocity ◽  
Lumped Parameter ◽  
The Impact

The interior ballistics simulations in 9 mm small gun chamber were conducted by implementing the process into the mixture multiphase model of Fluent V6.3 platform. The pressure of the combustion chamber, the velocity, and the travel of the projectile were investigated. The performance of the process, namely, the maximum pressure, the muzzle velocity, and the duration of the process was assessed. The calculation method is validated by the comparison of the numerical simulations results in the small gun with practical tests, and with lumped-parameter model results. In the current numerical study, both the characteristics and the performance of the interior ballistic process were reasonably predicted compared with the practical tests results. The impact of the weight charge on the interior ballistic performances was investigated. It has been found that the maximum pressure and the muzzle velocity increase with the increase of the charge weight.

scholarly journals Unjuk Kerja dan Pemeliharaan Gear Pump pada Unit Excavator 220 LC

2017 ◽  
Vol 5 (01) ◽  
pp. 55-66
Author(s):  
Veny Selviyanty.YH
Keyword(s):  
Material Testing ◽  
Fluid Power ◽  
Gear Pump ◽  
Positive Displacement ◽  
Non Destructive

Gear pump (pompa roda gigi) adalah jenis pompa positive displacement dimana fluida akan mengalir melalui celah-celah roda gigi dengan dinding rumahnya disebut sebagai pompa karena fluida yang dialirkan pada umumnya berupa cairan (liquid) atau bubur (slurry). Sedangkan pompa positive displacement berarti pompa tersebut menghisap sejumlah fluida yang terjebak yang kemudian ditekan dan dipindahkan ke arah keluaran (outlet). Gear pump sering digunakan untuk aplikasi hydrolic fluid power. Dalam pengoperasiannya sebuah komponen gear pump excavator dapat mengalami kegagalan, meskipun komponen tersebut masih dalam keadaan bagus/ baru. Untuk menganalisa penyebab terjadi kegagalan gear pump ini dilakukan pengujian yang meliputi pengujian yang bersifat merusak (destructive material testing) menggunakan uji kekerasan dan pengujian yang tidak merusak (non-destructive material testing) menggunakan uji fraktografi, metallografi dan pengujian komposisi kimia. Dari hasil pemeriksaan di labor menunjukan bahwa Gear Pump Excavator mengalami kerusakan pada gigi penggerak di bagian luar dan gigi bagian dalam, photo makro roda gigi bagian luar dalam penampang melintang menunjukan adanya cacat Deformasi / Perubahan Bentuk akibat beban bentur pada permukaan roda gigi. Roda gigi yang menerima beban putar/ gesek mengalami aus sesuai dengan arah putaran geardan pada permukaan patahan dan menunjukkan terdapatnya inklusi yang terkonsentrasi mengarah ke permukaan material gear pump excavator sehingga menyebabkan terjadinya aus. Pada material gear pump excavator  yang mengalami kegagalan bila dilihat dari bentuk patahannya termasuk kepada jenis beban fatik  karena sebelum patah gear pump excavator  mengalami cacat deformasi.

A Novel Positive Displacement Axial Piston Machine With Bent Cylinder Sleeves

2021 ◽  
Author(s):  
Swarnava Mukherjee ◽  
Antonio Masia ◽  
Mark Bronson ◽  
Lizhi Shang ◽  
Andrea Vacca
Keyword(s):  
Elastohydrodynamic Lubrication ◽  
Lumped Parameter Model ◽  
Cylinder Block ◽  
Element Analysis ◽  
Frictional Loss ◽  
Positive Displacement ◽  
Piston Cylinder ◽  
Lumped Parameter ◽  
Axial Piston Machine ◽  
Axial Piston

Abstract In this paper, an investigation of a novel positive displacement axial piston machine using a bent cylinder sleeve configuration is presented. The proposed design eliminates the side moments on the piston/cylinder interface, therefore, reduces the frictional loss and improves the total energy efficiency. A multi-physics elastohydrodynamic lubrication model was used to aid the design of the piston/cylinder and the cylinder block/port block interface. Then, a lumped parameter model was used to optimize the port block geometry. Groove geometry was chosen primarily to reduce flow ripple, tilting moment, and cavitation risk. To improve the housing stiffness, the lumped parameter model was combined with a finite element analysis. This ensured safety for the testing. In the end, steady-state experiments were performed on the prototype based on the ISO4409 normative. The unit’s speed was set to 500 rpm, then increased by 500 rpm until it reached 3000 rpm. The supply pressure was set to 20 bar. The outlet pressure was set to 70 bar at first, then increased by 50 bar until it reached 220 bar. The results show a remarkable volumetric efficiency with a peak of 99.5%. It is however noted that due to some of the issues with the initial iteration of the current design, there is a reduction in mechanical efficiency. The causes and possible future solutions to these issues are discussed in the manuscript.

scholarly journals Viscous Loss Analysis of the Flooded Electro-Hydrostatic Actuator Motor under Laminar and Turbulent Flow States

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 975
Author(s):  
Yanpeng Li ◽  
Zongxia Jiao ◽  
Tian Yu ◽  
Yaoxing Shang
Keyword(s):  
Calculation Method ◽  
Heat Dissipation ◽  
Cfd Simulation ◽  
Viscous Friction ◽  
Lumped Parameter Model ◽  
Friction Loss ◽  
Gradient Theory ◽  
Flow State ◽  
Lumped Parameter ◽  
Viscous Loss

The electro-hydrostatic actuator (EHA) is one of the most prevalent types of power-by-wire (PBW) actuation systems. With the increase in EHA power density, using the pump’s leakage oil to cool the motor has been gradually adopted to solve the problem of excessive motor temperature. However, the viscous friction loss caused by the liquid viscosity will seriously affect the heat dissipation effect and dynamic performance of the motor. To calculate the motor viscosity loss accurately, a novel calculation method is proposed in this paper. Using the energy gradient theory, the relationship between the fluid flow state and the rotation speed is analyzed. In addition, the lumped parameter model of viscous loss is established by using the conservation of momentum theory and computational fluid dynamics (CFD) simulation. A test rig is designed to test the viscous friction loss for various rotation speeds, and the test results show a good agreement with the theoretical analysis. The present results demonstrate the effectiveness of the lumped parameter model and provide a better calculation method for wet motor viscosity loss calculation.

scholarly journals Theoretical Investigation into the Ripple Source of External Gear Pumps

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 535 ◽  
Author(s):  
Xinran Zhao ◽  
Andrea Vacca
Keyword(s):  
Fluid Power ◽  
Flow Pulsation ◽  
Positive Displacement ◽  
System A ◽  
Novel Approach ◽  
Lumped Parameter ◽  
External Gear Pumps ◽  
Gear Pumps ◽  
Increasing Demand ◽  
Good Interpretation

External gear pumps are among the most popular fluid power positive displacement pumps, however they often suffer of excessive flow pulsation transmitted to the downstream circuit. To meet the increasing demand of quiet operation for modern fluid power system, a better understanding of the ripple source of gear pumps is desirable. This paper presents a novel approach for the analysis of the ripple source of gear pumps based on decomposition into a kinematic component and a pressurization component. The pump ripple can be regarded as the superposition of the displacement solution and the pressurization solution. The displacement solution is driven by the kinematic flow, and it can be derived from the kinematic flow theory; instead, the pressurization solution can be approximated by overlapping the pressurization flow for a single displacement chamber. Furthermore, in this way the changes of these two components with modification of the delivery circuit are determined in both analytical and numerical ways. The result of this analysis provides a good interpretation of the pulsation simulated by a detailed lumped-parameter simulation model, thus showing its validity. The result also indicates that the response of two ripple sources to the change of the loading in the downstream hydraulic circuit is very different. These findings reveal the limitation of the traditional experimental method for determining the pump ripple, that new experimental methods which are more physics-based can be potentially formulated based on this work.

scholarly journals CFD Simulation of a Post-Compensated Load Sensing Directional Control Valve

2021 ◽  
Vol 312 ◽  
pp. 05002
Author(s):  
Paola Fresia ◽  
Massimo Rundo
Keyword(s):  
Pressure Drop ◽  
Cfd Simulation ◽  
Control Valve ◽  
Design Tool ◽  
Lumped Parameter Model ◽  
Cfd Model ◽  
Load Sensing ◽  
Directional Control ◽  
Lumped Parameter ◽  
Directional Control Valve

The paper presents the CFD model of a load sensing directional control valve. The model was validated experimentally in terms of pressure drop and flow force at different positions of the spool. The spool position was imposed manually by means of a micrometric screw and a load cell was used for measuring the flow force. The CFD model was developed with the CAD-embedded tool FloEFD®. The model has been proved to be very reliable in estimating the pressure drop, moreover quite good results were obtained also in the evaluation of the flow force. The CFD simulations were used to tune the coefficients of a lumped parameter model of the valve, so that such a model can be efficiently used for the simulation of an entire hydraulic circuit. Moreover, the CFD model has been used as design tool for attenuating the detrimental effect of the flow force. In particular, the width of the land upstream of the metering edge has an influence on the resultant force on the spool. If was found that it is possible to significantly reduce the flow force at maximum opening with a relatively small increment of the pressure drop across the valve.

An Assessed Model for the Vibro-Acoustic Analysis of Gear Pumps

2013 ◽  
Author(s):  
Emiliano Mucchi ◽  
Giorgio Dalpiaz
Keyword(s):  
Finite Element ◽  
Boundary Element ◽  
Acoustic Analysis ◽  
Simulated Data ◽  
Element Model ◽  
Lumped Parameter Model ◽  
Fe Model ◽  
Gear Pump ◽  
Operational Conditions ◽  
Lumped Parameter

In this work a combined model for the vibro-acoustic analysis of an external gear pump for automotive applications is presented and experimentally assessed. The model includes a lumped-parameter model, a finite-element model and a boundary-element model. The lumped-parameter (LP) model regards the interior parts of the pump (bearing blocks and gears), the finite element (FE) model regards the external parts of the pump (casing and end plates), while the boundary element (BE) model estimates the noise generation in operational conditions. Attention has been devoted to the inclusion of the oil effect inside the pump casing: the fluid-structure interaction between oil and pump casing was taken into account. The model has been assessed using experiments: the experimental accelerations and acoustic pressure measured in operational conditions have been compared with the simulated data coming from the combined LP/FE/BE model. Eventually, model results and limitations are presented.

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