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.

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.

An Innovative Device for Passive Control of Surge in Industrial Compression Systems

2000 ◽  
Author(s):  
Gianmario L. Arnulfi ◽  
Pietro Giannattasio ◽  
Diego Micheli ◽  
Piero Pinamonti
Keyword(s):  
Passive Control ◽  
Experimental Tests ◽  
Control Device ◽  
Operating Conditions ◽  
Compression System ◽  
Multi Stage ◽  
Lumped Parameter ◽  
Wide Range ◽  
Optimal Values ◽  
Parameter Approach

The present paper reports a numerical-experimental study on the dynamic behaviour of a compression system based on a multi-stage centrifugal blower and fitted with an innovative device for the dynamic suppression of surge instability. The control device is of passive type and is based on the aeroelastic coupling of the basic compression system with a hydraulic oscillator. The controlled system is modelled at first by using a non-linear lumped parameter approach. The simulated system dynamics within a wide range of operating conditions allows a parametric analysis to be performed and the optimal values of the control parameters to be singled out. Such optimal values are then used to design the hydraulic oscillator, which results in a technically feasible and very simple configuration. Finally, experimental tests are carried out on the compression plant with and without the passive control device, which demonstrate the effectiveness of the proposed control system in suppressing surge instabilities, at least within the limits predicted by the numerical simulation.

scholarly journals Performance Assessment of Bladeless Micro-Expanders Using 3D Numerical Simulation

2019 ◽  
Vol 113 ◽  
pp. 03016 ◽  
Author(s):  
Avinash Renuke ◽  
Alberto Traverso ◽  
Matteo Pascenti
Keyword(s):  
Shear Stress ◽  
Cfd Simulation ◽  
Numerical Data ◽  
Flow Density ◽  
Cfd Analysis ◽  
Mixing Zone ◽  
Sst Turbulence Model ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results ◽  
First Time

This paper summarizes the development of fully 3D Computational Fluid Dynamics (CFD) analysis for bladeless air micro expander for 200 W and 3 kW rated power. Modelling of nozzle along with rotor is done using structured mesh. This analysis, for the first time, demonstrates the interaction between nozzle and rotor using compressible flow density-based solver. The Shear Stress Transport (SST) turbulence model is employed to resolve wall effects on the rotor and to determine the shear stress accurately. The results illustrate the flow field inside stator and rotor along with complicated mixing zone between stator and rotor. The comparison of rotor-stator CFD simulation results is done with experiments to preliminary validate the model. The losses in the turbine are discussed with the help of experimental and numerical data.

Passive control of microclimate in museum display cases: A lumped parameter model and experimental tests

2015 ◽  
Vol 16 (4) ◽  
pp. 413-418 ◽  
Author(s):  
Francesco Romano ◽  
Luigi P.M. Colombo ◽  
Mirco Gaudenzi ◽  
Cesare M. Joppolo ◽  
Luigi P. Romano
Keyword(s):  
Passive Control ◽  
Experimental Tests ◽  
Lumped Parameter Model ◽  
Lumped Parameter ◽  
Museum Display

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 Lumped parameter model and experimental tests on a pressure limiter for variable displacement pumps

2020 ◽  
Vol 197 ◽  
pp. 07005
Author(s):  
Paola Fresia ◽  
Massimo Rundo
Keyword(s):  
Experimental Tests ◽  
Control Flow ◽  
Lumped Parameter Model ◽  
Load Sensing ◽  
Axial Piston Pumps ◽  
Discharge Coefficients ◽  
Lumped Parameter ◽  
Variable Displacement ◽  
Flow Through ◽  
And Control

The paper presents the lumped parameter model of a pressure limiter for axial piston pumps developed in the Simcenter Amesim® environment. The control includes both the absolute and differential (load sensing) pressure limiter in a single body. The continuous position valve was tested experimentally alone on a test rig in order to estimate the discharge coefficients required for tuning the model. The tests were performed at imposed positions of the spool and the corresponding modulated pressure and control flow through the valve were measured. A contactless transducer was used for measuring with a very high accuracy the spool position. The influence of the bleed orifice on the pressure gain was also measured experimentally. It was found that the discharge coefficients have a significant influence on the hydraulic characteristic of the valve with also a consequence on the dynamic behavior of the entire displacement control.

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 Assessing Groundwater Residence Time in a Highly Anthropized Unconfined Aquifer Using Bomb Peak 14C and Reconstructed Irrigation Water 3H

Radiocarbon ◽  
2013 ◽  
Vol 55 (2) ◽  
pp. 993-1006 ◽  
Author(s):  
Paul Baudron ◽  
Florent Barbecot ◽  
Marina Gillon ◽  
José Luis García Aróstegui ◽  
Yves Travi ◽  
...  
Keyword(s):  
Residence Time ◽  
Agricultural Development ◽  
Input Function ◽  
Exponential Model ◽  
Unconfined Aquifer ◽  
Lumped Parameter Model ◽  
Aquifer System ◽  
Lumped Parameter ◽  
Recharge Rates ◽  
Recent Variation

Radiocarbon decay is rarely used to assess the residence time of modern groundwater due to the low resolution of its long half-life in comparison to the expected range of ages. Nonetheless, the modern 14C peak induced by the nuclear bomb tests traces efficiently the impacts of recent human activities on groundwater recharge, as well as for tritium. A simple lumped parameter model (LPM) was implemented in order to assess the interest of 14C and 3H nuclear peaks in a highly anthropized aquifer system of southeastern Spain under intense agricultural development. It required i) to assess a correction factor for modern 14C activities and ii) to reconstruct the 3H recharge input function, affected by irrigation. In such a complex hydrogeological context, an exponential model did not provide satisfying results for all samples. A better solution was reached by taking into account the qualitative recent variation of the recharge rates into a combined exponential flow and piston flow model. Apart from presenting an uncommon approach for 14C dating of modern groundwater, this study highlights the need of considering not only the variation of the tracer but also the variability of recharge rates in LPMs.

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.

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