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Gear Pumps and Motors

A special issue of Energies (ISSN 1996-1073).

Deadline for manuscript submissions: closed (10 March 2023) | Viewed by 47059
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Special Issue Editors


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Guest Editor
Department of Engineering "Enzo Ferrari", University of Modena and Reggio Emilia, Modena & Reggio Emilia, Italy
Interests: fluid power; internal combustion engines; gear pumps and motors

E-Mail Website
Guest Editor
Department of Engineering "Enzo Ferrari", University of Modena and Reggio Emilia, Modena & Reggio Emilia, Italy
Interests: fluid power systems; fluid power components; gear pumps and motors

Special Issue Information

Dear Colleagues,

Positive displacement pumps and motors are key components and play a relevant role in determining the efficiency of fluid power systems. Especially nowadays, when the typical low efficiency levels of fluid power systems are under severe analysis and critics, the attention and interest of researchers of the field is particularly high and especially devoted to identify designs, materials and technologies able to improve the efficiency of positive displacement pumps and motors. While a lot of work has been devoted to some architectures of these machines, such as the swashplate axial piston pumps, gear pumps and motors have been studied with minor continuity and interest.

However, gear pumps and motors are extensively used in fluid power applications because of the many positive aspects related to them: depending on the different architectures, they can be characterized by robustness, low cost, ability to work with contaminated fluid, more or less quietness.

This special issue will collect works from authors all around the world that have dedicated their studies to gear pumps and motors, with the aim of publish and disseminate research approaches and results regarding the study of gear pumps and motors.

The contributions may be focused on one or more of the following topics:

 -modelling and simulation of the pumps and motors operation, alone or as a part of a system

 -experimental characterizations

 -new materials and new manufacturing technologies

 -operation with eco-fluids

 -optimization of the design

 -cavitation analysis

 -lubrication modelling and efficiency consideration

 -analysis of systems and applications in which the role of the gear pump or motor is a key role

 -noise and vibration

Prof. Massimo Borghi
Dr. Barbara Zardin
Guest Editors

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Keywords

  • modelling and simulation of the pumps and motors operation, alone or as a part of a system
  • experimental characterizations
  • new materials and new manufacturing technologies
  • operation with eco-fluids
  • optimization of the design
  • cavitation analysis
  • lubrication modelling and efficiency consideration
  • analysis of systems and applications in which the role of the gear pump or motor is a key role
  • noise and vibration

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Published Papers (13 papers)

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Research

19 pages, 6285 KiB  
Article
Applied Methodology for Designing and Calculating a Family of Spur Gear Pumps
by Ionuţ Gabriel Ghionea
Energies 2022, 15(12), 4266; https://doi.org/10.3390/en15124266 - 10 Jun 2022
Cited by 2 | Viewed by 2969
Abstract
The paper presents in an applicative manner a parameter-based methodology about design, modeling and optimization of a spur gear pump, currently under production in a Romanian company. Wanting to expand their product range, the company asked for a parameter-based design of this type [...] Read more.
The paper presents in an applicative manner a parameter-based methodology about design, modeling and optimization of a spur gear pump, currently under production in a Romanian company. Wanting to expand their product range, the company asked for a parameter-based design of this type of pump, FEM simulations and optimization of its conception to cover a wider range of flow rates, as required by current beneficiaries. The purpose of this research was to find improved alternative solutions via parametric design, mathematical validation and finite element simulation of the manufacturing solutions. The pump model is well known and has been manufactured for decades in many countries, under various licenses and constructive variants. The research process analyzed the functional role of the gear pump, its structure, its 3D model, which was reconstructed from the last manufactured solution, while identifying certain dimensions to be optimized and used in parametric design relations. The author used the CATIA V5 software and Visual Basic programing language. By mathematical computation, there were identified the pressure values and forces generated in the pump’s gears, applied later in FEM simulations to check the behavior of the pump components at the loads generated by these forces and pressures. The paper identifies and presents in a summary table the maximum stress values, deformations and percentages of computation errors for each pump’s constructive solution. Full article
(This article belongs to the Special Issue Gear Pumps and Motors)
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14 pages, 981 KiB  
Article
Evaluation Methodology of Rotary Flow Dividers Used as Pressure Intensifiers with Creation of a New Pressure Multiplying Efficiency
by Jakub Milan Hradecký, Antonín Bubák and Martin Dub
Energies 2022, 15(6), 2293; https://doi.org/10.3390/en15062293 - 21 Mar 2022
Cited by 2 | Viewed by 2422
Abstract
For most of the technical community, rotary flow dividers are known for synchronization of two or more hydraulic actuators. However, there is also a possibility to use them for pressure multiplication, flow regeneration, or speed control. For those applications, there is a need [...] Read more.
For most of the technical community, rotary flow dividers are known for synchronization of two or more hydraulic actuators. However, there is also a possibility to use them for pressure multiplication, flow regeneration, or speed control. For those applications, there is a need to describe the behavior of its quantities. This article reveals a new evaluation methodology for rotary flow dividers when they are unconventionally used as pressure multipliers and also reveals a new quantity-pressure multiplying efficiency. Then, there is an experiment provided between two rotary flow dividers with different designs, where there is a new evaluation methodology used. On the base of that, it is possible to compare and decide which divider is more likely to be used in multiplying circuits and more suitable for further investigation from the perspective of new designs. With this evaluation methodology, it is possible to compare much more than two different dividers. It is possible to run more tests and experiments with arbitrary dividers, and their new design changes to reach as efficient a pressure multiplication or flow regeneration as possible. Full article
(This article belongs to the Special Issue Gear Pumps and Motors)
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22 pages, 6326 KiB  
Article
An Investigation of the Vibration Modes of an External Gear Pump through Experiments and Numerical Modeling
by Sangbeom Woo and Andrea Vacca
Energies 2022, 15(3), 796; https://doi.org/10.3390/en15030796 - 22 Jan 2022
Cited by 8 | Viewed by 3561
Abstract
This paper presents an experimental and numerical modal analysis for an external gear pump considering its mounting on a test rig in a laboratory setting. Most of the previous studies on experimental modal analysis (EMA) of hydraulic pumps focused on the modal frequencies [...] Read more.
This paper presents an experimental and numerical modal analysis for an external gear pump considering its mounting on a test rig in a laboratory setting. Most of the previous studies on experimental modal analysis (EMA) of hydraulic pumps focused on the modal frequencies to allow model validation. However, the mode shapes of pump bodies have not extensively been discussed. Furthermore, the nature of the pump components assembly and mounting poses some modeling challenges, such as the uncertain material properties of each component, the behavior of the bolted joints, and some critical modeling boundary conditions related to pump mounting. In this regard, the experimentally obtained vibration modes of a reference pump using the least-square complex exponential (LSCE) method are analyzed with an emphasis on the characteristics of the mode shapes. Then, simple modeling strategies are proposed and validated by performing the analysis from the component level to the full assembly. As a result, the mode shapes are categorized depending on the type of motions that the modes exhibit. It is observed that the pump casing does not show any substantial deformation but is close to the rigid body motion. Moreover, without considerably increasing model complexities, the proposed numerical approach provides reasonable accuracy with average errors in modal frequencies of 6%, as well as good agreement in terms of mode shapes. The vibration reduction strategy is briefly discussed based on the measured mode shapes, and the proposed modeling approaches can be useful to study external gear pumps with minimal model complexities yet allowing reasonable result accuracy. Full article
(This article belongs to the Special Issue Gear Pumps and Motors)
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23 pages, 10401 KiB  
Article
Model of the Floating Bearing Bushing Movement in an External Gear Pump and the Relation to Its Parameterization
by Miquel Torrent, Pedro Javier Gamez-Montero and Esteban Codina
Energies 2021, 14(24), 8553; https://doi.org/10.3390/en14248553 - 18 Dec 2021
Cited by 7 | Viewed by 6341
Abstract
This article presents the modeling, simulation and experimental validation of the movement of the floating bearing bushing in an external gear pump. As a starting point, a complete pump parameterization was carried out through standard tests, and these parameters were used in a [...] Read more.
This article presents the modeling, simulation and experimental validation of the movement of the floating bearing bushing in an external gear pump. As a starting point, a complete pump parameterization was carried out through standard tests, and these parameters were used in a first bond graph model in order to simulate the gear pump behavior. This model was experimentally validated under working conditions in field tests. Then, a sophisticated bond graph model of the movement of the floating bushing was developed from the equations that define its lubrication. Finally, as a result, both models were merged by integrating the dynamics of the floating bushing bearing with the variation of the characteristic parameters (loss coefficients). Finally, the final model was experimentally validated both in laboratory and field tests by assembling the pump in a drilling machine to drive the auxiliary movements. The novelty of this article is the conception and construction of a simple and experimentally validated tool for the study of a gear pump, which relates its macroscopic behavior as a black box (defined by the loss coefficients) to the internal changes of the unit (defined by its internal lubrication). Full article
(This article belongs to the Special Issue Gear Pumps and Motors)
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22 pages, 6480 KiB  
Article
Evaluation of Pressure Resonance Phenomena in DCT Actuation Circuits
by Stefano Terzi, Luca Montorsi and Massimo Milani
Energies 2021, 14(5), 1354; https://doi.org/10.3390/en14051354 - 2 Mar 2021
Viewed by 1579
Abstract
The paper investigates hydraulic wave propagation phenomena through hydraulic circuits of power transmission systems by means of numerical approaches. The actuation circuit of a Dual-Clutch Transmission (DCT) power transmission system supplied by a Gerotor pump is analyzed. A steady state approach is adopted [...] Read more.
The paper investigates hydraulic wave propagation phenomena through hydraulic circuits of power transmission systems by means of numerical approaches. The actuation circuit of a Dual-Clutch Transmission (DCT) power transmission system supplied by a Gerotor pump is analyzed. A steady state approach is adopted to detect resonance phenomena due to Gerotor design parameters and circuit lengths, while one-dimensional numerical models are implemented to predict the pressure oscillations through the hydraulic ducts for the whole pump operating domain. CFD-1D pipelines are adopted to address the pressure oscillation behavior through the hydraulic pipeline, while spectral maps and order tracking techniques are used to evaluate their fluctuation intensity in function of the pump speed rate. The numerical models are validated with experimental tests performed on an ad hoc test rig for power transmission systems and a good match is found between the numerical and the experimental results. Pump design parameters as well as hydraulic accumulators and resonators are numerically investigated to quantitatively evaluate their improvement on the circuits’ hydro-dynamic behavior. Furthermore, simplified numerical models are implemented to investigate the frequency response behavior of the hydraulic circuits by means of linear analysis. This approach resulted to be particularly effective for the prediction of the resonance frequencies location, and it can be adopted as an optimization tool since significant simulation time can be saved. Finally, the performance of the circuits operating with an eco-friendly fluid is evaluated numerically and the results are compared with the ones obtained with a traditional petroleum-based oil. Full article
(This article belongs to the Special Issue Gear Pumps and Motors)
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26 pages, 11409 KiB  
Article
About the Influence of Eco-Friendly Fluids on the Performance of an External Gear Pump
by Gabriele Muzzioli, Luca Montorsi, Andrea Polito, Andrea Lucchi, Alessandro Sassi and Massimo Milani
Energies 2021, 14(4), 799; https://doi.org/10.3390/en14040799 - 3 Feb 2021
Cited by 6 | Viewed by 3764
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Gear Pumps and Motors)
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31 pages, 12331 KiB  
Article
Synthetic Approach to the Design, Manufacturing and Examination of Gerotor and Orbital Hydraulic Machines
by Jarosław Stryczek and Piotr Stryczek
Energies 2021, 14(3), 624; https://doi.org/10.3390/en14030624 - 26 Jan 2021
Cited by 5 | Viewed by 3271
Abstract
Gerotor technology is an important research area in the field of hydraulics which attracts the attention of both academic scientists and industry. Despite the numerous publications announced by academics, as well as a considerable number of projects made by industry, the subject has [...] Read more.
Gerotor technology is an important research area in the field of hydraulics which attracts the attention of both academic scientists and industry. Despite the numerous publications announced by academics, as well as a considerable number of projects made by industry, the subject has not been exhausted. This paper presents a new approach to gerotor technology which has been formed by gathering the authors’ knowledge of gerotors in a synthetic form. The following scientific and technical results have been obtained: (1) A uniform system of parameters and basic concepts regarding toothing and cycloidal gearing (z, m, λ, v, g) which is consistently used to describe the geometry, kinematics, hydraulics and manufacture of those elements; (2) description of the geometry and kinematics of the epicycloidal and hypocycloidal gears with the use of the adopted system of parameters. Additionally, the epicycloidal/hypocycloidal double gearing is presented, which is an original idea of the authors; (3) description of the hydraulics of the gerotor and orbital machines, and in particular: (i) determination of equations for delivery (capacity) q and irregularity of delivery (capacity) δ using the above-mentioned system of basic parameters; (ii) formulation of the principles of designing internal channels and clearances in the gerotor machines and presentation of the original disc distributor in the epicycloidal/hypocycloidal orbital motor; (iii) presentation of the methods of manufacturing the epicycloidal and hypocycloidal gearings with 12 examples of the systems implemented in practice; (4) presentation of the research methods applied for the examination of the gerotor machines, combining computer simulation and experimental research into a coherent and cohesive whole which results in the effect of research synergy. Such a synthesis of knowledge may serve the improvement, creation and investigation of gerotor and orbital machines carried out by academics and industry. Full article
(This article belongs to the Special Issue Gear Pumps and Motors)
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22 pages, 8450 KiB  
Article
A Numerical Analysis of an Innovative Flow Ripple Reduction Method for External Gear Pumps
by Gianluca Marinaro, Emma Frosina and Adolfo Senatore
Energies 2021, 14(2), 471; https://doi.org/10.3390/en14020471 - 17 Jan 2021
Cited by 30 | Viewed by 3583
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Gear Pumps and Motors)
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16 pages, 6511 KiB  
Article
Evaluation of Tooth Space Pressure and Incomplete Filling in External Gear Pumps by Means of Three-Dimensional CFD Simulations
by Alessandro Corvaglia, Massimo Rundo, Paolo Casoli and Antonio Lettini
Energies 2021, 14(2), 342; https://doi.org/10.3390/en14020342 - 9 Jan 2021
Cited by 25 | Viewed by 4013
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Gear Pumps and Motors)
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14 pages, 5249 KiB  
Article
Theoretical and Experimental Fatigue Strength Calculations of Lips Compensating Circumferential Backlash in Gear Pumps
by Piotr Osiński, Grzegorz Chruścielski and Leszek Korusiewicz
Energies 2021, 14(1), 251; https://doi.org/10.3390/en14010251 - 5 Jan 2021
Viewed by 2675
Abstract
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. [...] Read more.
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. Full article
(This article belongs to the Special Issue Gear Pumps and Motors)
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26 pages, 5680 KiB  
Article
Experimental Characterization and Evaluation of the Vibroacoustic Field of Hydraulic Pumps: The Case of an External Gear Pump
by Sangbeom Woo and Andrea Vacca
Energies 2020, 13(24), 6639; https://doi.org/10.3390/en13246639 - 16 Dec 2020
Cited by 5 | Viewed by 3233
Abstract
This paper presents the experimental characterization of the vibroacoustic fields and the evaluation of noise performances of hydraulic pumps. Research on hydraulic pump noise has traditionally focused on the fluid-borne noise sources, and very often the analyses of vibration and noise have been [...] Read more.
This paper presents the experimental characterization of the vibroacoustic fields and the evaluation of noise performances of hydraulic pumps. Research on hydraulic pump noise has traditionally focused on the fluid-borne noise sources, and very often the analyses of vibration and noise have been performed focusing on a few local points. This trend results in the lack of investigation on the overall behaviors of vibroacoustic fields of hydraulic pumps, and it has been one of the obstacles to understand the complete mechanisms of noise generation. Moreover, despite the existence of the ISO standards for the determination of noise levels, diverse metrics have been used for the evaluation of noise performances of the pumps, but the adequacy of these metrics has not been carefully examined. In this respect, this paper aims at introducing a way to characterize and interpret the measured vibroacoustic field and providing proper methods which are also capable of applying the ISO standards for the fair assessment of pump noise performances. For the characterization of the vibroacoustic field, operational deflection shapes (ODS) and corresponding radiated sound fields are visualized at harmonics of the pumping frequency by using a spectral analysis. Observations are made regarding the motions of the pump and its mounting plate and the resultant radiated noise, depending on the frequency, as well as their correlation. A numerical analysis using the Rayleigh integral equation is also performed to further investigate the contribution of the mounting plate motion on the noise radiation. For the evaluation of noise performance, two different units are tested at multiple operating conditions, and comparisons are made based on their measured sound power levels (SWLs) and sound pressure levels (SPLs). The results emphasize the importance of SWL measurement for the fair noise performance evaluation, and the two methods are proposed as practices to determine the minimum number of measurement points for practicability and to have reliable sound power determination for hydraulic pumps. Full article
(This article belongs to the Special Issue Gear Pumps and Motors)
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22 pages, 7454 KiB  
Article
CFD Analyses of Textured Surfaces for Tribological Improvements in Hydraulic Pumps
by Paolo Casoli, Fabio Scolari, Massimo Rundo, Antonio Lettini and Manuel Rigosi
Energies 2020, 13(21), 5799; https://doi.org/10.3390/en13215799 - 5 Nov 2020
Cited by 5 | Viewed by 2412
Abstract
In any hydraulic machine there are lubricated couplings that could become critical beyond certain operating conditions. This paper presents the simulation results concerning textured surfaces with the aim of improving the performance of lubricated couplings in relative motion. The texturing design requires much [...] Read more.
In any hydraulic machine there are lubricated couplings that could become critical beyond certain operating conditions. This paper presents the simulation results concerning textured surfaces with the aim of improving the performance of lubricated couplings in relative motion. The texturing design requires much care to obtain good improvements, and it is essential to analyze both the geometric features of the dimples and the characteristics of the coupled surfaces, like the sliding velocity and gap height. For this purpose, several CFD simulations have been performed to study the behavior of the fluid bounded in the coupling, considering dimples with different shapes, size, and spatial distribution. The simulations consider the onset of gaseous cavitation to evaluate the influence of this phenomenon on the pressure distribution generated by the textured surface. The analyses have pointed out that it is critical to correctly predict the behavior of the textured surface in the presence of local cavitation, in fact, when cavitation occurs, the characteristic time of the transient in which the phase of the fluid change is very rapid and it is comparable to the time taken by the fluid to move from one dimple to the next. Full article
(This article belongs to the Special Issue Gear Pumps and Motors)
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24 pages, 11926 KiB  
Article
Thermal Modelling of External Gear Machines and Experimental Validation
by Rituraj Rituraj, Andrea Vacca and Mario Antonio Morselli
Energies 2020, 13(11), 2920; https://doi.org/10.3390/en13112920 - 6 Jun 2020
Cited by 7 | Viewed by 3722
Abstract
The flow of energy within external gear machines (EGMs) leads to the variation of fluid temperature in the EGMs, which affects their performance. However, the common approaches for the simulation of EGMs assume isothermal conditions. This isothermal assumption negatively impacts their modelling accuracy [...] Read more.
The flow of energy within external gear machines (EGMs) leads to the variation of fluid temperature in the EGMs, which affects their performance. However, the common approaches for the simulation of EGMs assume isothermal conditions. This isothermal assumption negatively impacts their modelling accuracy in terms of the internal flows which are dependent on the fluid temperature (via fluid properties). This paper presents a lumped parameter based thermal model of EGMs where the fluid temperature in the EGM is evaluated considering the effects of compression/expansion, internal flows, and power losses. Further, numerical techniques are developed to model each of these three aspects. The thermal model is validated via the outlet temperature and volumetric efficiency measurements obtained from experiments conducted on six units of an EGM taken as a reference with different internal clearances. The results from the model show that the fluid temperature increases as it is carried from the inlet side to the outlet side during the pumping operation. However, the fluid at the ends of the shafts has the highest temperature. By comparing the isothermal simulation results with the proposed thermal model, the results also point out how the isothermal assumption becomes inaccurate, particularly in conditions of low volumetric efficiency. Full article
(This article belongs to the Special Issue Gear Pumps and Motors)
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