scholarly journals Gear mesh geometry effect on performance improvement for external gear pumps

2019 ◽  
Vol 287 ◽  
pp. 01007 ◽  
Author(s):  
Viktor Ivanov ◽  
Dimitar Karaivanov ◽  
Svitlana Ivanova ◽  
Mariia Volkova
Keyword(s):  
Performance Improvement ◽  
Flow Rate ◽  
Bending Strength ◽  
Fluid Volume ◽  
Radial Clearance ◽  
The Finite Element Method ◽  
Gear Mesh ◽  
External Gear Pumps ◽  
Pump Flow Rate ◽  
Gear Pumps

The parameters of the involute and cycloidal gearing which influence on fluid volume at the tooth space are analysed. It is established that to a greater extent on the flow rate of the pump with involute gearing is influenced by the radial clearance coefficient and the profile shift coefficient. The radii ratio of the auxiliary and pitch circles, as well as the radial clearance coefficient, mainly affect the flow rate of the pump with cycloidal gearing. Since the gear module is determined for reasons of pump flow rate, the teeth has a significant safety factor for contact stress and especially bending stress. This allows a wide variation of the gearing parameters in greater limits than in transmissions. The dependences of the fluid volume at the tooth space in the cycloidal gearing on the radial clearance coefficient, on the radii ratio of the auxiliary and pitch circles, on the fillet radius coefficient, is found. The boundaries of the variation of the gearing parameters were established taking into account the bending strength of the teeth. The analysis is carried out using the finite element method. Recommendations for the use of cycloidal gearing in external gear pumps have been developed.

A Robust Design Optimization Methodology for External Gear Pumps

2010 ◽  
Author(s):  
Emiliano Mucchi ◽  
Gabriele Tosi ◽  
Roberto d’Ippolito ◽  
Giorgio Dalpiaz
Keyword(s):  
Robust Design ◽  
High Speed ◽  
Optimization Process ◽  
Robust Design Optimization ◽  
Radial Clearance ◽  
Vibration Level ◽  
Oil Viscosity ◽  
Pump Operation ◽  
External Gear Pumps ◽  
Gear Pumps

This work addresses the topic of external gear pumps for automotive applications, which operate at high speed and low pressure. In previous works of the authors, a hybrid lumped-parameter/finite-element model has been developed, in order to foresee the pump dynamic behaviour in terms of gear and casing acceleration. The model includes the main important phenomena involved in the pump operation and it has been validated on the basis of experimental data. In this research, an original optimization process has been applied to such a hybrid model in order to reduce the pump vibration level, i.e. the acceleration of the external casing. The set up of the optimization process comprises a single objective (case accelerations) and some operational and geometrical input variables (oil viscosity, oil Bulk modulus, relief groove dimension and radial clearance in the journal bearings). This paper compares three optimization methodologies for the optimization of the pump vibration level. In particular common optimization processes based on simulations are compared with a combined analysis based, firstly, on Design Of Experiments (DOE) and Response Surface Modelling (RSM) and, secondly, on the application of evolutionary algorithms to reach the optimal variable combination. The different methodologies are compared in terms of time efficiency and accuracy in the solution. Finally, a robust design process has been carried out in order to consider the manufacturing tolerances of the real pump and assess their effect on the performance of the component. The results offer important information and design insights that would be very difficult to obtain without such procedures.

scholarly journals Modeling the Efficiency of External Gear Pumps Based on Similarity Considerations

2018 ◽  
Author(s):  
C. Schänzle ◽  
N. Störmer ◽  
P. F. Pelz
Keyword(s):  
Power Consumption ◽  
Flow Rate ◽  
Volume Flow Rate ◽  
Measurement Data ◽  
Volume Flow ◽  
Operating Conditions ◽  
Gear Pump ◽  
Industrial Sectors ◽  
External Gear Pumps ◽  
Gear Pumps

Gear pumps are used in numerous different applications and industrial sectors. However, when selecting a suitable gear pump for a specified application, manufacturers are often confronted with a lack of comparable measurement data for the desired combination of operating conditions and pumping fluid. Consequently, an estimation of the volume flow rate and the power consumption of a pump under the operating conditions of the application is necessary. In this context, this paper discusses the application of similarity on external gear pumps and presents its validation by means of measured pump characteristics. Seven gear pumps of different displacement volume are measured at different operating conditions varying pressure, rotational speed and the viscosity of the pumping fluid. The validation results prove that similarity is useful to represent a pump’s characteristic over a wide operating range. The prediction of the volume flow rate and the power consumption at a changed viscosity show good accuracy. However, the scaling of the pump characteristic based on the displacement volume show contradictory results.

scholarly journals Theoretical and Experimental Fatigue Strength Calculations of Lips Compensating Circumferential Backlash in Gear Pumps

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 251
Author(s):  
Piotr Osiński ◽  
Grzegorz Chruścielski ◽  
Leszek Korusiewicz
Keyword(s):  
Maximum Stress ◽  
Theoretical Calculations ◽  
Fatigue Loading ◽  
Minimum Thickness ◽  
Bending Tests ◽  
External Gear Pumps ◽  
Gear Pumps ◽  
In Series ◽  
Number Of Cycles ◽  
Technical Solutions

This article presents theoretical and experimental calculations of the minimum thickness of a compensation lip used in external gear pumps. Pumps of this type are innovative technical solutions in which circumferential backlash (clearance) compensation is used to improve their volumetric and overall efficiency. However, constructing a prototype of such a pump requires long-lasting research, and the compensation lip is its key object, due to the fact that it is an element influenced by a notch and that it operates in unfavorable conditions of strong fatigue stresses. The theoretical calculations presented in this article are based on identifying maximum stress values in a fatigue cycle and on implementing the stress failure condition and the conditions related to the required value of the fatigue safety factor. The experimental research focuses on static bending tests of the lips as well as on the fatigue loading of the lips in series of tests at increasing stress values until lip failure due to fatigue. The tests allowed the minimum lip thickness to be found for the assumed number of fatigue cycles, which is 2.5 times the number of cycles used in wear margin tests.

Numerical Characterization of Hot Gas Ingestion Through Turbine Rim Seals

2016 ◽  
Author(s):  
Riccardo Da Soghe ◽  
Cosimo Bianchini ◽  
Carl M. Sangan ◽  
James A. Scobie ◽  
Gary D. Lock
Keyword(s):  
Flow Rate ◽  
Numerical Study ◽  
Axial Flow ◽  
Radial Clearance ◽  
Buffering Effect ◽  
Hot Gas ◽  
Numerical Predictions ◽  
Wide Range ◽  
Thermal Buffering

This paper deals with a numerical study aimed at the characterization of hot gas ingestion through turbine rim seals. The numerical campaign focused on an experimental facility which models ingress through the rim seal into the upstream wheel-space of an axial-turbine stage. Single-clearance arrangements were considered in the form of axial- and radial-seal gap configurations. With the radial-seal clearance configuration, CFD steady-state solutions were able to predict the system sealing effectiveness over a wide range of coolant mass flow rates reasonably well. The greater insight of flow field provided by the computations illustrates the thermal buffering effect when ingress occurs: for a given sealing flow rate, the effectiveness on the rotor was significantly higher than that on the stator due to the axial flow of hot gases from stator to rotor caused by pumping effects. The predicted effectiveness on the rotor was compared with a theoretical model for the thermal buffering effect showing good agreement. When the axial-seal clearance arrangement is considered, the agreement between CFD and experiments worsens; the variation of sealing effectiveness with coolant flow rate calculated by means of the simulations display a distinct kink. It was found that the “kink phenomenon” can be ascribed to an over-estimation of the egress spoiling effects due to turbulence modelling limitations. Despite some weaknesses in the numerical predictions, the paper shows that CFD can be used to characterize the sealing performance of axial- and radial-clearance turbine rim seals.

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.

Numerical Characterization of Hot-Gas Ingestion Through Turbine Rim Seals

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Riccardo Da Soghe ◽  
Cosimo Bianchini ◽  
Carl M. Sangan ◽  
James A. Scobie ◽  
Gary D. Lock
Keyword(s):  
Flow Rate ◽  
Numerical Study ◽  
Axial Flow ◽  
Radial Clearance ◽  
Buffering Effect ◽  
Hot Gas ◽  
Numerical Predictions ◽  
Wide Range ◽  
Thermal Buffering

This paper deals with a numerical study aimed at the characterization of hot-gas ingestion through turbine rim seals. The numerical campaign focused on an experimental facility which models ingress through the rim seal into the upstream wheel-space of an axial-turbine stage. Single-clearance arrangements were considered in the form of axial- and radial-seal gap configurations. With the radial-seal clearance configuration, computational fluid dynamics (CFD) steady-state solutions were able to predict the system sealing effectiveness over a wide range of coolant mass flow rates reasonably well. The greater insight of flow field provided by the computations illustrates the thermal buffering effect when ingress occurs: For a given sealing flow rate, the effectiveness on the rotor was significantly higher than that on the stator due to the axial flow of hot gases from stator to rotor caused by pumping effects. The predicted effectiveness on the rotor was compared with a theoretical model for the thermal buffering effect showing good agreement. When the axial-seal clearance arrangement is considered, the agreement between CFD and experiments worsens; the variation of sealing effectiveness with coolant flow rate calculated by means of the simulations displays a distinct kink. It was found that the “kink phenomenon” can be ascribed to an overestimation of the egress spoiling effects due to turbulence modeling limitations. Despite some weaknesses in the numerical predictions, the paper shows that CFD can be used to characterize the sealing performance of axial- and radial-clearance turbine rim seals.

Does the Blood Pump Flow Rate have an Impact on the Dialysis Dose During Low Dialysate Flow Rate Hemodialysis?

2018 ◽  
Vol 46 (4) ◽  
pp. 279-285 ◽  
Author(s):  
Maxime Leclerc ◽  
Clémence Bechade ◽  
Patrick Henri ◽  
Elie Zagdoun ◽  
Erick Cardineau ◽  
...  
Keyword(s):  
Flow Rate ◽  
Blood Pump ◽  
Bivariate Analysis ◽  
Dialysis Dose ◽  
Dialysate Flow ◽  
Pump Flow ◽  
Dialysate Flow Rate ◽  
Pump Flow Rate ◽  
A Prospective Study ◽  
The Impact

We conducted a prospective study to assess the impact of the blood pump flow rate (BFR) on the dialysis dose with a low dialysate flow rate. Seventeen patients were observed for 3 short hemodialysis sessions in which only the BFR was altered (300,350 and 450 mL/min). Kt/V urea increased from 0.54 ± 0.10 to 0.58 ± 0.08 and 0.61 ± 0.09 for BFR of 300, 400 and 450 mL/min. For the same BFR variations, the reduction ratio (RR) of β2microglobulin increased from 0.40 ± 0.07 to 0.45 ± 0.06 and 0.48 ± 0.06 and the RR phosphorus increased from 0.46 ± 0.1 to 0.48 ± 0.08 and 0.49 ± 0.07. In bivariate analysis accounting for repeated observations, an increasing BFR resulted in an increase in spKt/V (0.048 per 100 mL/min increment in BPR [p < 0.05, 95% CI (0.03–0.06)]) and an increase in the RR β2m (5% per 100 mL/min increment in BPR [p < 0.05, 95% CI (0.03–0.07)]). An increasing BFR with low dialysate improves the removal of urea and β2m but with a potentially limited clinical impact.

Silica Nanocomposite Membrane for Dehumidification

2017 ◽  
Author(s):  
Omar Almahmoud ◽  
Tae-Youl Choi ◽  
Young-Soo Seo ◽  
Hyo-Sun Kim ◽  
Kevin A. Johnson
Keyword(s):  
Water Vapor ◽  
Flow Rate ◽  
Driving Forces ◽  
Comsol Multiphysics ◽  
The Finite Element Method ◽  
Dry Air ◽  
Hydrophobic Polymer ◽  
Silica Nanocomposite ◽  
Novel Design ◽  
Polyurethane Membrane

Various designs of novel membrane (silica nanocomposite polyurethane membrane) were tested for its optimal configuration in a membrane-based dehumidification system. This membrane was designed with a hydrophobic polymer matrix with hydrophilic silica nanochains. In this dehumidification process, two driving forces were suggested: concentration gradient of water vapor in the atmospheric air channel due to sweep gas and pressure gradient due to vacuum. This paper describes validation of the model configurations using the finite element method software (COMSOL Multiphysics) with experiments. Pressurized air enters an air duct at 1–5 liters per minute flow rate. Air is then humidified using a misting nozzle until saturation. Then the humid air passes by the membrane with a vacuum pump connected vertically to the duct to maximize the dehumidification rate. A novel design showed water vapor reduction from 19.4 grams of water vapor per kilogram of dry air to 16.9 grams of water vapor per kilogram of dry air for the 1 liter per minute flow rate of the 47 mm diameter membrane.

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.

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