Computer Prediction of Cyclic Excitation Sources for an External Gear Pump

1985 ◽  
Vol 199 (3) ◽  
pp. 175-180 ◽  
Author(s):  
K Foster ◽  
R Taylor ◽  
I M Bidhendi
Keyword(s):  
Computer Program ◽  
Gear Pump ◽  
Computer Prediction ◽  
Pressure Distributions ◽  
External Gear Pumps ◽  
Theoretical Predictions ◽  
Gear Pumps ◽  
External Gear Pump

A description is given of a computer program for investigating the performance of the external gear pumps under varying conditions with the special emphasis on the examination of pressure distributions within the pump, i.e. excitation forces for the vibration of the pump case and the variation in flow generated by the pump. Measurements are presented for the variation with time of tooth space pressure and the results are compared with the theoretical predictions from the computer program.

The Flow Pulsation Analysis of an External Gear Pump

2011 ◽  
Vol 236-238 ◽  
pp. 2327-2331
Author(s):  
Yan Zhi Li ◽  
Li Huan Gao ◽  
Xiao Yang Tang
Keyword(s):  
Pulse Amplitude ◽  
Gear Pump ◽  
Flow Pulsation ◽  
Flow Ripple ◽  
Pump Flow ◽  
External Gear Pumps ◽  
Tooth Width ◽  
Different Types ◽  
Gear Pumps ◽  
External Gear Pump

In this paper, the theoretical flow ripple of an external gear pump is studied for pumps of similar size using different numbers of teeth on the driving and driven gears. External gear pumps with three different types of tooth profiles are studied. Nondimensional flowrates and fluctuation coefficients of gear pumps are discussed. By using the formula, flowrates can be calculated accurately and efficiently. Results indicate that: in the case of the same displacement (except teeth number and tooth width, other parameters of the gear pump are the same) the gear pump flow pulsation decreases with the increasing of the teeth number. We also concluded that changing tooth profiles on the driving and driven gear can get different pulse amplitude of the flow ripple.

scholarly journals The Influence of Radial and Axial Gaps on Volumetric Efficiency of External Gear Pumps

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4468
Author(s):  
Paulina Szwemin ◽  
Wieslaw Fiebig
Keyword(s):  
Fluid Flow ◽  
Volumetric Efficiency ◽  
Operating Parameters ◽  
Gear Pump ◽  
Cfd Model ◽  
External Gear Pumps ◽  
Flow Phenomena ◽  
Gear Pumps ◽  
The Impact ◽  
External Gear Pump

The design of gear pumps and motors is focused on more efficient units which are possible to achieve using advanced numerical simulation techniques. The flow that appears inside the gear pump is very complex, despite the simple design of the pump itself. The identification of fluid flow phenomena in areas inside the pump, considering the entire range of operating parameters, is a major challenge. This paper presents the results of simulation studies of leakages in axial and radial gaps in an external gear pump carried out for different gap shapes and sizes, as well as various operating parameters. To investigate the processes that affect pump efficiency and visualize the fluid flow phenomena during the pump’s operation, a CFD model was built. It allows for a detailed analysis of the impact of the gears’ eccentricity on leakages and pressure build-up on the circumference. Performed simulations made it possible to indicate the relationship between leakages resulting from the axial and radial gap, which has not been presented so far. To verify the CFD model, experimental investigations on the volumetric efficiency of the external gear pump were carried out. Good convergence of results was obtained; therefore, the presented CFD model is a universal tool in the study of flow inside external gear pumps.

A Numerical Procedure to Design the Optimal Axial Balance of Pressure Compensated Gear Machines

2014 ◽  
Author(s):  
Divya Thiagarajan ◽  
Andrea Vacca
Keyword(s):  
Numerical Procedure ◽  
Operating Conditions ◽  
Force Balance ◽  
Gear Pump ◽  
Power Losses ◽  
Outlet Port ◽  
External Gear Pumps ◽  
Gear Pumps ◽  
Force Components ◽  
External Gear Pump

This paper presents an innovative numerical procedure to determine the optimal balancing area of lateral bushes in external gear pumps or motors. In pressure compensated designs of external gear machines, the lateral bushes perform the important functions of sealing the tooth space volumes while they transfer fluid from the inlet to the outlet port. In normal operating conditions, a lubricating gap exists between the lateral bush and the gear permitting to minimize losses due to shear stress and leakage. These conditions are found by determining proper balancing areas at the side of the bushes not facing the gears, in which the pressure of the high pressure port is properly established. This problem is also known as “axial balance” of external gear machines. To determine the optimal axial balance which minimizes the power losses associated with the lubricating gap in all operating conditions, all the static and hydrodynamic forces acting on the lateral bushes have to be considered. This delicate aspect of external gear units design is usually addressed through empirical procedures; while in this paper an automatic numerical procedure is presented. The proposed method is based on the solution of the force balance of the lateral bushes, taking into account all force components, including the hydrodynamic terms due to the relative inclination between bushes and gears and material deformation. After detailing the procedure, the paper describes its potentials by showing the advantages arising from the optimization of the axial balance of a particular external gear pump for fluid power applications.

Efficiency of External Gear Pump

2021 ◽  
pp. 53-61
Author(s):  
N.L. Velikanov ◽  
V.A. Naumov
Keyword(s):  
Mechanical Efficiency ◽  
Fuel Oil ◽  
Pump Efficiency ◽  
Gear Pump ◽  
Technical Data ◽  
External Gear Pumps ◽  
Gear Pumps ◽  
Load Characteristics ◽  
External Gear Pump ◽  
Research Show

The purpose of the research was to analyze the load characteristics of external gear pumps. As the initial data, the results of factory tests of the NMSH and SH pumps, provided by HMS Livgidromash JSC, were used. The load characteristics of the gear pump NMSH32-10 were constructed, and the dependence of this pump efficiency on the dimensionless pressure and Hersey number was given. The efficiency of the SH 40-4 pump was recalculated according to the test data. Findings of research show that for diesel fuel and oil, the calculated efficiency differs from the values indicated in the technical data sheet by more than 25%, while for fuel oil they differ slightly. This testifies to the non-monotonic dependence between the SH 40-4 pump efficiency and the viscosity. In the entire investigated range of pressures, with an increase in the viscosity of the pumped liquid, the efficiency first increases and then noticeably decreases. The paper presents the dependence of the volumetric and mechanical efficiency of the SH 40-4 pump on the Hersey number at three values of the viscosity of the pumped liquid.

The Research on the Theory of Flow and Method of Ripple Control of the External Gear Pump Group

2013 ◽  
Vol 706-708 ◽  
pp. 1827-1830
Author(s):  
Li Juan Yu ◽  
Xue Cheng Zhang ◽  
Xiao Dong Wang
Keyword(s):  
Quadratic Function ◽  
Gear Pump ◽  
Flow Pulsation ◽  
Amplitude Variation ◽  
Instantaneous Flow ◽  
Theory Of Flow ◽  
External Gear Pumps ◽  
Gear Pumps ◽  
External Gear Pump ◽  
Ripple Control

In this paper, the theory of flow and method of ripple control of the external gear pump group are studied with two same-parameter external gear pumps which are installed in the form of parallel and different phase. In this thesis, the external gear pump group is known as a low ripple gear pump group, and the theory of ripple control is based on the theory that two periodic and quadratic function curves of different phase superposition can reduce the amplitude variation. According to this method, the thesis starts to analyze the instantaneous flow of the low ripple gear pump group, moreover which are compared with the instantaneous flow of a single gear pump. Finally, it is concluded that the flow pulsation rate of low ripple pump group is equal to 1/4 times of a single pump flow pulsation.

scholarly journals Research on Identification Method of Wear Degradation of External Gear Pump Based on Flow Field Analysis

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 4058
Author(s):  
Rui Guo ◽  
Yongtao Li ◽  
Yue Shi ◽  
Hucheng Li ◽  
Jingyi Zhao ◽  
...  
Keyword(s):  
Flow Field ◽  
Internal Flow ◽  
Accelerated Life Test ◽  
Field Analysis ◽  
Gear Pump ◽  
External Gear Pumps ◽  
Gear Pumps ◽  
Flow Field Analysis ◽  
External Gear Pump ◽  
Degradation State

As a kind of hydraulic power component, the external gear pump determines the performance of the entire hydraulic system. The degradation state of gear pumps can be monitored by sensors. Based on the accelerated life test (ALT), this paper proposes a method to identify the wear degradation state of external gear pumps based on flow field analysis. Firstly, the external gear pump is theoretically analyzed. Secondly, dynamic grid technology is used to simulate the internal flow field of the gear pump in detail. Finally, the theoretical and simulation results are verified by the ALT. The results show that this method can effectively identify the wear degradation status of four sample pumps. The results of the work not only provide a solution to the research on the wear degradation of external gear pumps, but also provide strong technical support for the predictive maintenance of hydraulic pumps.

Experimental Investigation of Flowrate Irregularity in Rotary Gear Pumps

1992 ◽  
Author(s):  
G. Mimmi
Keyword(s):  
Experimental Investigation ◽  
Flow Rate ◽  
Experimental Tests ◽  
Periodic Variation ◽  
Experimental Results ◽  
Gear Pump ◽  
Gear Pumps ◽  
Hot Film ◽  
Instantaneous Flow Rate ◽  
External Gear Pump

Abstract In a previous paper the author proposed a method to reduce the periodic variation in flow rate for an external gear pump. To verify the experimental results, a series of experimental tests on a expressly realized gear pump, was carried out. The pump was equipped with relieving grooves milled into the side plates. The tests were done on a closed piping specifically realized and equipped for measuring the instantaneous flow rate of the fluid through a wedge-shaped hot film probe.

Review of Gear Pump Development at NRL

2020 ◽  
Author(s):  
Logan T. Williams
Keyword(s):  
System Development ◽  
Design Guidelines ◽  
Lessons Learned ◽  
Naval Research ◽  
Gear Pump ◽  
Pump Design ◽  
External Gear Pumps ◽  
Gear Pumps ◽  
Original Goal ◽  
Small Form Factor

Abstract Research into hydraulic quadrupeds at the US Naval Research Laboratory (NRL) has created the demand for in-house development of miniaturized hydraulic components, including pumps. As part of this effort to develop a miniaturized hydraulic powertrain, external gear pumps were examined, designed, and iterated upon to create an efficient pump package with a small form factor (1.5 × 1.6 × 1.8 inches). The evolution of the pump design has touched every component of the pump and has resulted in many practical design guidelines, novel pump components, and improved pump analysis tools. The original goal of developing the capability for integrated hydraulic powertrain components, such as embedding the pump into the quadruped’s hydraulic manifold, was to enable further compaction and streamlined system development. An additional result of the project was the accumulation of gear pump design fundamentals and lessons learned that can benefit any pump designer.

Vibroacoustic Measurements and Simulations Applied to External Gear Pumps. An Integrated Simplified Approach

2016 ◽  
Vol 41 (2) ◽  
pp. 285-296 ◽  
Author(s):  
Eleonora Carletti ◽  
Giuseppe Miccoli ◽  
Francesca Pedrielli ◽  
Giorgio Parise
Keyword(s):  
Complex Dynamics ◽  
Gear Tooth ◽  
Fluid Pressure ◽  
Sound Intensity ◽  
Integrated Approach ◽  
Gear Pump ◽  
Simplified Approach ◽  
Noise Field ◽  
Gear Pumps ◽  
External Gear Pump

Abstract This paper describes the development phases of a numerical-experimental integrated approach aimed at obtaining sufficiently accurate predictions of the noise field emitted by an external gear pump by means of some vibration measurements on its external casing. Harmonic response methods and vibroacoustic analyses were considered as the main tools of this methodology. FFT acceleration spectra were experimentally acquired only in some positions of a 8.5 cc/rev external gear pump casing for some working conditions and considered as external excitation boundary conditions for a FE quite simplified vibroacoustic model. The emitted noise field was computed considering the pump as a ‘black box’, without taking into account the complex dynamics of the gear tooth meshing process and the consequent fluid pressure and load distribution. Sound power tests, based on sound intensity measurements, as well as sound pressure measurements in some positions around the pump casing were performed for validation purposes. The comparisons between numerical and experimental results confirmed the potentiality of this approach in offering a good compromise between noise prediction accuracy and reduction of experimental and modelling requirements.

Experimental Validation of a Model for the Dynamic Analysis of Gear Pumps

2013 ◽  
Author(s):  
Emiliano Mucchi ◽  
Giorgio Dalpiaz
Keyword(s):  
Experimental Validation ◽  
Gear Pump ◽  
Test Plate ◽  
Operational Conditions ◽  
Experimental Apparatus ◽  
Gear Pumps ◽  
Force Components ◽  
Set Up ◽  
The Time Domain ◽  
External Gear Pump

This paper concerns the experimental validation of an elastodynamic model of an external gear pump for steering systems in vehicles. The elastodynamic model takes into account the most important phenomena involved in the operation of this kind of machines. Two main sources of noise and vibration can be considered: pressure and gear meshing. An experimental apparatus has been set up for the measurements of the case accelerations and force components in operational conditions. The model was validated by comparison between simulations and experimental results concerning forces and moments: it deals with the external and inertia components acting on the gears, estimated by the model, and the reactions and inertia components on the pump case and the test plate, obtained by measurements. The validation is carried out comparing the level of the time synchronous average in the time domain and the waterfall maps in the frequency domain, with particular attention to identify system resonances. The validation results are globally satisfactory.

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