Showing papers on "Gear pump published in 2021"

Three-dimensional model of an external gear pump with an experimental evaluation of the flow ripple:

Abstract: A three-dimensional model of an external gear pump and a new application of an algorithm for the measurement of the unsteady flow rate in hydraulic pipes are presented. The experimental delivery fl...

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

Abstract: 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.

Design and Analysis of Conjugated Straight-Line Internal Gear Pairs

Abstract: In comparison to involute internal gear pumps, conjugated straight-line internal gear pumps have the advantages of smaller trapped volume, lower flow ripple, and higher reliability. Conjugated straight-line internal gear pumps were invented by Truninger in 1966; however, because of their unique line type, the main characteristics of these pumps are still not completely understood. Internal gear pairs are the key component of these pumps. To better understand the performance of these pumps, the present research focused on the design of an internal gear pair. A numerical model was developed to demonstrate the design method of the conjugated straight-line internal gear pair. To point out the effective engagement of the gear pair, three fundamental requirements were considered—a conjugated point existed in the tooth profile, no interference occurred during the meshing process, and the overlap coefficient was greater than one. Furthermore, according to the design of the gear pair, flow characteristics and some optimization suggestions for tooth parameters were proposed. The main characteristics of the gear pair were compared with those of an involute gear pair. Finally, a conjugated straight-line internal gear pair machined by the linear cutting method was tested, and the obtained results revealed that the design method was correct.

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

Abstract: 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 Analysis of an Innovative Flow Ripple Reduction Method for External Gear Pumps

Abstract: In this paper, an innovative solution to minimize noise emission, acting on the flow ripple, in a prototype External Gear Pump (EGP) is presented. Firstly, a new tool capable to completely simulate this pump’s typologies, called EgeMATor, is presented; the hydraulic model, adopted for the simulation, is based on a lumped parameter method using a control volume approach. Starting from the pump drawing, thanks to different subroutines developed in different environments interconnected, it is possible to analyze an EGP. Results have been compared with the outputs of a three-dimensional CFD numerical model built up using a commercial code, already used with success by the authors. In the second section, an innovative solution to reduce the flow ripple is implemented. This technology is called Alternative Capacitive Volumes (ACV) and works by controlling and uniformizing the reverse flow, performing a consistent reduction of flow non-uniformity amplitude. In particular, a high reduction of the flow non-uniformity is notable in the frequency domain on the second fundamental frequency. The technology is easy to accommodate in a pump housing, especially for high-pressure components, and it helps with reducing the fluid-borne noise.

Research on Prediction Method of Hydraulic Pump Remaining Useful Life Based on KPCA and JITL

Abstract: Hydraulic pumps are commonly used; however, it is difficult to predict their remaining useful life (RUL) effectively. A new method based on kernel principal component analysis (KPCA) and the just in time learning (JITL) method was proposed to solve this problem. First, as the research object, the non-substitute time tac-tail life experiment pressure signals of gear pumps were collected. Following the removal and denoising of the DC component of the pressure signals by the wavelet packet method, multiple characteristic indices were extracted. Subsequently, the KPCA method was used to calculate the weighted fusion of the selected feature indices. Then the state evaluation indices were extracted to characterize the performance degradation of the gear pumps. Finally, an RUL prediction method based on the k-vector nearest neighbor (k-VNN) and JITL methods was proposed. The k-VNN method refers to both the Euclidean distance and angle relationship between two vectors as the basis for modeling. The prediction results verified the feasibility and effectiveness of the proposed method. Compared to the traditional JITL RUL prediction method based on the k-nearest neighbor algorithm, the proposed prediction model of the RUL of a gear pump presents a higher prediction accuracy. The method proposed in this paper is expected to be applied to the RUL prediction and condition monitoring and has broad application prospects and wide applicability.

Finite Element Modeling of a Viscous Fluid Flowing through an External Gear Pump

Abstract: Gear pumps are frequently used for the transport of high-viscosity fluids, for instance, for the extrusion of polymers. The flow rate of this extrusion process is regularly controlled by an external gear pump. In this work, the 2D flow of a viscous fluid through such an external gear pump is studied using the finite element method. Local mesh refinement based on the respective distance between moving boundaries is essential to capture the relatively narrow clearances in the pump. The gear pump works against the pressure driven flow, therefore its performance is strongly dependent on material and processing parameters. The flow of Newtonian and shear-thinning fluids through the external gear pump is studied for a range of processing conditions. Pump curves are obtained that display the volumetric efficiency against the Hersey number, which is defined as viscosity times rotation speed divided by pressure difference over the pump. Analysis of the residence time of the fluid in the pump, shows that vortices are present in the inflow channel causing material to remain in the pump for longer times.

A Virtual Prototype for Fast Design and Visualization of Gerotor Pumps

Abstract: In the context of generation of lubrication flows, gear pumps are widely used, with gerotor-type pumps being specially popular, given their low cost, high compactness, and reliability. The design process of gerotor pumps requires the simulation of the fluid dynamics phenomena that characterize the fluid displacement by the pump. Designers and researchers mainly rely on these methods: (i) computational fluid dynamics (CFD) and (ii) lumped parameter models. CFD methods are accurate in predicting the behavior of the pump, at the expense of large computing resources and time. On the other hand, Lumped Parameter models are fast and they do not require CFD software, at the expense of diminished accuracy. Usually, Lumped Parameter fluid simulation is mounted on specialized black-box visual programming platforms. The resulting pressures and flow rates are then fed to the design software. In response to the current status, this manuscript reports a virtual prototype to be used in the context of a Digital Twin tool. Our approach: (1) integrates pump design, fast approximate simulation, and result visualization processes, (2) does not require an external numerical solver platforms for the approximate model, (3) allows for the fast simulation of gerotor performance using sensor data to feed the simulation model, and (4) compares simulated data vs. imported gerotor operational data. Our results show good agreement between our prediction and CFD-based simulations of the actual pump. Future work is required in predicting rotor micro-movements and cavitation effects, as well as further integration of the physical pump with the software tool.

Numerical Analysis of Standard - Unstandard Gears for an External Gear Pumps

Abstract: The most widely of hydraulic applications power employed source that including low manufacturing costs and good performance are defined as the external gear pumps. In this study, the using of unstandard gears and influence on the performance of gear pumps are studied. These influences include pulsation factor of flow rate, flow rate of pump and trapped volume between two meshing gears. Matlab software has been used to evaluate performance by modifying algorithm and deriving the equations of pump flow rate. The unstandard gear is used in the study undertaken with +0.3 Rack shift coefficient. Results indicated the using of unstandard gears increase flow rate and reduce the trapped volume and pulsation flow rate factor. It was concluded that the factor of pulsation flow rate reduces as increase of teeth number which leads to pulsation flow rate stabilization.

Design Multistage External Gear Pumps for Dry Sump Systems: Methodology and Application

Abstract: Thanks to their manufacturing simplicity, robustness, and consolidated design knowledge, external gear pumps are widely adopted in the automotive fields. With the purpose of leading the design procedure of these positive displacement machines, within this work, the authors integrate in a comprehensive tool the salient equations adopted for the design of the major gear pump features. The presented procedure is devoted to the design of multistage external gear pumps characterized by a singular floating driving shaft supported by fluid-dynamic journal bearings. Focusing the attention on the procedure flexibility, it has been structured in three iterative calculation phases. The core section of the methodology concerns the geometrical design of the involute gear tooth profile. It is oriented to ensure a proper volumetric displacement while complying with the space requirement and the tooth manufacturing limitations. Thus, through the analytical pressure loads estimation combined with the operational parameters, the second calculation step provides the design of the driving shaft and the relevant dimensions of the journal bearings. Finally, by means of a power loss approach, the third macrosection of the procedure leads to estimating the clearances between gear tip and housing. The potentials of the methodology are exposed by describing its applications to a case study of multistage gear pump employed in the dry sump lubrication system of an automotive heavy-duty engine. Each calculation step application is outlined with reference to the proposed analytical formulation and the results of the parameters calibration are presented. Within this context, the procedure is assessed by means of a CFD analysis. The results highlight the accuracy of the methodology on the estimation of the required delivery flow rate. Aside from being accurate, flexible, and reliable, the procedure stands out for being an innovative tool within the multistage gear pump framework.

FMECA and MFCC-Based Early Wear Detection in Gear Pumps in Cost-Aware Monitoring Systems

Abstract: Gear pump failures in industrial settings are common due to their exposure to uneven high-pressure outputs within short time periods of machine operation and uncertainty. Improving the field and line clam are considered as the solutions for these failures, yet they are quite insufficient for optimal reliability. This research, therefore, suggests a method for early wear detection in gear pumps following an extensive failure modes, effects, and criticality analysis (FMECA) of an AP3.5/100 external gear pump manufactured by BESCO. To replicate this condition, fine particles of iron oxide (Fe2O3) were mixed with the experimental fluid, and the resulting vibration data were collected, processed, and exploited for wear detection. The intelligent wear detection process was explored using various machine learning algorithms following a mel-frequency cepstral coefficient (MFCC)-based discriminative feature extraction process. Among these algorithms, extensive performance evaluation reveals that the random forest classifier returned the highest test accuracy of 95.17%, while the k-nearest neighbour was the most cost efficient following cross validations. This study is expected to contribute to improved evaluations of gear pump failure diagnosis and prognostics.

Tribological analysis of the plain bearings in an external gear pump

Abstract: Tribological loads in the plain bearings of external gear pumps are influenced by system-specific parameters (e.g. elasticity of the components, micro-geometry and manufacturing tolerances) and the operating point (rotation speed, operating pressure and temperature of the pressure medium). Due to the pressure build-up in the tooth chambers, fluctuating radial forces are acting on the gear shafts and lead to complex deformations of the bearing bushings and the housing. These deformations have an influence on the tribological loads in the plain bearings. To decrease tribological loads and failure rates, it is possible to modify the plain bearings in terms of their micro-geometry (e.g. clearance and contours) or to take constructive measures on the overall system (e.g. on the bearing bushings). Therefore, it is necessary to understand the influences of external loads, elastic environment and micro-geometry on the tribological loads in the plain bearings. This paper describes the first steps to understand these interactions by building up a simulation model of a specific external gear pump using the MBS/EHD-tool FIRST developed by IST [1]. The focus is to evaluate the required modeling depth regarding the consideration of an elastic housing.

About the influence of eco-friendly fluids on the performance of an external gear pump

Abstract: This paper wants to investigate the effects of eco-friendly fluids on the thermo-fluid-dynamic performance of external gear pumps in order to provide a first response to the increasingly urgent demands of the green economy. A computational fluid dynamics (CFD) approach based on the overset mesh technique was developed for the simulation of the full 3D geometry of an industrial pump, including all the characteristic leakages between components. A sensibility analysis of the numerical model with respect to different fluid properties was performed on a commonly used mineral oil, showing the key role of the fluid compressibility on the prediction of the pump volumetric efficiency. Moreover, the influence of temperature internal variations on both fluid density and viscosity were included. The BIOHYDRAN TMP 46 eco-friendly industrial oil and olive oil were further considered in this work, and the results of the simulations were compared for the three fluid configurations. A slightly lower volumetric efficiency was derived for the olive oil application against the other two conditions, but suggestive improvements were produced in terms of pressure and temperature distributions. Therefore, based on the obtained results, this paper encourages research activity towards the use of eco-friendly fluids in the hydraulic field.

Parameterization, modeling, and validation in real conditions of an external gear pump

Abstract: This article presents a methodology for predicting the fluid dynamic behavior of a gear pump over its operating range. Complete pump parameterization was carried out through standard tests, and these parameters were used to create a bond graph model to simulate the behavior of the unit. This model was experimentally validated under working conditions in field tests. To carry this out, the pump was used to drive the auxiliary movements of a drilling machine, and the experimental data were compared with a simulation of the volumetric behavior under the same conditions. This paper aims to describe a method for characterizing any hydrostatic pump as a “black box” model predicting its behavior in any operating condition. The novelty of this method is based on the correspondence between the variation of the parameters and the internal changes of the unit when working in real conditions, that is, outside a test bench.

Efficiency of External Gear Pump

Abstract: 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.

Cavitation in Positive Displacement Pumps

Abstract: Positive displacement pumps are an integral part of many applications, ranging from fuel systems in the transportation sector and the petrochemical industry to precise flow-metering devices used in the biomedical field. A common characteristic of such devices is the varying shape and volume of the geometry enclosing the transferred liquid. This fact renders modeling and investigation of their operation rather difficult. In this chapter, different methods that can be employed to tackle such issues will be discussed. Furthermore, indicative examples of a high-pressure fuel pump and a gear pump will be discussed along with thermodynamic phenomena that take place, such as compression heating. Furthermore, factors that affect the performance and cavitation formation in such devices will be demonstrated.

A Novel Design of Electro-hydraulic Driven Active Powered Ankle-Foot Prosthesis

Abstract: This paper presents the design and control architecture of a full active powered ankle prosthesis driven by electro-hydrostatic actuator (EHA) to improve amputee gait during the level-ground walking in full-time gait cycle. A 100 W brushless DC motor driving a 0.92 cc/rev bi-directional gear pump serves as the power kernel. An elastic element is configured in series connection with the hydraulic cylinder as energy store unit. With this architecture, better power characteristic, ability of energy storage and passive compliance were obtained to revive sound human characteristic as much as possible. To smooth the gait pattern, a neuromuscular model with Hill-type muscle tendon structure is introduced into the control system scheduled by finite state machine which was designed to carry on different control strategy during individual gait phase. The overall simulation was established utilizing MATLAB/Simulink platform to validate its feasibility.

The performance capabilities of the journal bearings as a supports of the fuel gear pump of the gas turbine engine

Abstract: The paper is about the performance capability of the journal bearings as a support of the fuel gear pump for gas turbine engines (GTE). Supports of the external gear pump usually operate in semi-dry friction conditions, which reduces residual life and is one of the limiting factors. For this investigation, the serial gear pump was chosen with the following parameters: the number of teeth z = 14, module m = 3.8, gear-loading Р = 7800 N. The authors have studied options for a pump with an electrical and mechanical (from the rotor of the GTE) drive. The main criterion for studying the bearing capacity is the minimum thickness of the working layer of a fluid with low viscosity (kerosene). For modeling, a common theory is used based on solutions of differential equations of the viscous fluid hydrodynamics, which relate pressure, velocity, and viscous shear resistance. For technological reasons, the minimum allowable kerosene layer is limited to 5 μ m. The conducted analysis considers the multi-lobe (2-, 3- and 4-lobe) bearings with different lobe orientations relative to the force vector. It was found that the 2-lobe bearing has the best load capacity (provides the largest layer of kerosene). According to the results of the previous investigation for further work, the 2-lobe bearing was chosen. The influence of load, setting gap, eccentricity, the specific radius of lobe curvature, shaft length on the bearing load capacity was analyzed. A rational type of bearing design was proposed based on the load capacity criterion (the minimum layer of working fluid). It was shown that the hydrodynamic 2-lobe bearing can be sufficiently effective for the supports of the gear fuel pumps of GTE. Based on the results of the investigation, 2 variants of the pumping unit designs were proposed. The first one for the pump driven by the gas turbine engine rotor with parameters z = 19, m = 3.3, gears width B = 34, shaft diameter DS = 48, and shaft length LS = 56 (P = 10.2kN). The second one for the electrically driven pump, z = 28, m = 1,8, B = 15, DS = 34, and LS = 41 (P = 3.8 kN). The minimum angular velocity for the pump variants is 470 and 1055 rad/s, respectively. According to the investigation results, it was proposed to conduct related studies of the working process in pumps and bearings.

A CFD-Based Comparison of Different Positive Displacement Pumps for Application in Future Automatic Transmission Systems

Abstract: The efficiency requirements for hydraulic pumps applied in automatic transmissions in future generations of automobiles will increase continuously. In addition, the pumps must be able to cope with multiphase flows to a certain extent. Given this background, a balanced vane pump (BVP), an internal gear pump (IGP) and a three-dimensional geared tumbling multi chamber (TMC) pump are analyzed and compared by a computational fluid dynamics (CFD) approach with ANSYS CFX and TwinMesh. Furthermore, test bench measurements are conducted to obtain experimental data to validate the numerical results. The obtained numerical results show a reasonable agreement with the experimental data. In the first CFD setup, the conveying characteristics of the pumps with pure oil regarding volumetric efficiencies, cavitation onset and pressure ripple are compared. Both the IGP and the BVP show high volumetric efficiencies and low pressure ripples whereas the TMC shows a weaker performance regarding these objectives. In the second CFD setup, an oil-bubbly air multiphase flow with different inlet volume fractions (IGVF) is investigated. It can be shown that free air changes the pumping characteristics significantly by increasing pressure and mass flow ripple and diminishing the volumetric efficiency as well as the required driving torque. The compression ratios of the pumps appear to be an important parameter that determines how the multiphase flow is handled regarding pressure and mass flow ripple. Overall, the BVP and the IGP show both a similar strong performance with and without free air. In the current development state, the TMC pump shows an inferior performance because of its lower compression ratio and therefore needs further optimization.

Electric submersible gear pump installation

Abstract: FIELD: pumps.SUBSTANCE: invention relates to the installation of an electric submersible gear pump. Gear pump 4 is assembled from one or more pumping pair couples with chevron, spur, two helical gears with opposite inclination, involute engagement or Novikov teeth engagement, resting on a thrust washer and enclosed in one or more housing-sections 8, having a profiled suction channel to each pumping pair couples connecting the annulus with the formation fluid through a filter. The discharge channels are connected to the collector of body-section 8 and the collector of pump 4, which communicates with the pump and compressor pipes of the suspension. Between electric motor 2 and pump 4 there is chamber of seals 3 with intermediate shaft 11 on sliding supports with thrust bearing 12, at the ends of which there are two seals 13 of the contact, contact-slot or slot type with fixed or floating rings, to which copper tube 14 is connected that makes it possible to maintain the pressure inside higher than behind the housing and above the pump suction pressure by 0.03-0.05 MPa.EFFECT: invention is aimed at improving the reliable and long-term operation of the installation.3 cl, 4 dwg

Diesel engine fuel injection gear pump

Abstract: FIELD: mechanical engineering.SUBSTANCE: disclosed are methods and systems for diesel engine fuel injection gear pump. In one example front end of engine comprises an intermediate gear engaged with the first end of a crankshaft and a driving gear of a fuel pump engaged with the intermediate gear. The front end of the pump can additionally comprise a fuel pump, with input shaft of the fuel pump being directly connected to the driving gear of the fuel pump.EFFECT: the technical result consists in reducing lateral load on bearings of the fuel pump as well as reducing friction loss and extending service life of the fuel pump.18 cl, 18 dwg

Apparatus and method for thermal compensation during additive manufacturing

Abstract: An additive manufacturing apparatus includes an extruder and a gear pump in fluid communication with extruder. The additive manufacturing apparatus also includes a nozzle in fluid communication with the gear pump. The extruder is connected to a guide member such that at least a portion of the extruder is configured to expand and move along the guide member according to a thermal expansion of the extruder.

Liquid injection device of storage battery

Abstract: The invention discloses a liquid injection device of a storage battery. The liquid injection device comprises a base, and a plurality of liquid injection bottles which are arranged on the top part ofthe base from the left to the right, a gear pump, a vacuum pump, a driving mechanism and a quantifying mechanism, wherein the driving mechanism comprises a gear box, a first rotating shaft and a second rotating shaft which are arranged in the gear box and used for driving the gear pump and the vacuum pump respectively, a first gear arranged on the first rotating shaft and a second gear arranged onthe second rotating shaft, a third gear is arranged between the first gear and the second gear in a meshing mode and is a half gear, and the third gear is connected with a third rotating shaft through a connecting mechanism. According to the liquid injection device, the gear pump and the vacuum pump work in a staggered manner through the driving mechanism, and meanwhile, the driving mechanism isquantitatively arranged through the connecting mechanism without influencing the work of the gear pump and the vacuum pump, so that sufficient internal formation can be carried out in time and space when the electrolyte is injected into the storage battery, and the use stability of the battery is improved; the quantitative filling of the electrolyte is realized.

Self-aligning gear pump

Abstract: Disclosed herein is a gear pump (100) for pumping a fluid (404). The gear pump comprises: a sealed internal chamber (102); a pumping chamber (104) within the sealed internal chamber; a first pump port (122) fluidically connected to the pumping chamber; a second pump port (114) fluidically connected to the pumping chamber; a drive gear (120) within the pumping chamber; an idler gear (122) within the pumping chamber, wherein the drive gear and the idler gear are configured for pumping the fluid between the first pump port and the second pump port; a drive shaft (124) coupled to the drive gear, wherein the drive shaft is configured for rotationally driving the drive gear, wherein the drive shaft is within the sealed internal chamber; an idler shaft (126) coupled to the idler gear, wherein the idler shaft is within the sealed internal chamber, wherein the idler gear is coupled to the idler shaft; a pump housing (106, 108, 110) formed from a first housing element (106), a central housing element (108), and a second housing element (110), wherein the central housing element is positioned between the first housing element and the second housing element, wherein the first housing element, the second housing element and the central housing element form at least a portion of the sealed internal chamber, wherein the pumping chamber is formed entirely within the central housing; a first drive shaft bearing (128), wherein the first drive shaft bearing is mounted partially within the first housing element; a second drive shaft bearing (130), wherein the second drive shaft bearing is mounted partially within the second housing element, wherein the first drive shaft bearing and the second drive shaft bearing both partially extends into and align the drive gear with the pumping chamber; a first idler shaft bearing (132), wherein the first idler shaft bearing is mounted partially within the first housing; a second idler shaft bearing (134), wherein the second idler shaft bearing is mounted partially within the second housing element, wherein the first idler shaft bearing and the second idler shaft bearing both partially extends into the pumping chamber and align the idler gear with the pumping chamber.