scholarly journals Development tendencies of clearance compensation methods in internal gear pumps

2021 ◽  
Vol 338 ◽  
pp. 01021
Author(s):  
Piotr Osiński ◽  
Michał Stosiak ◽  
Paweł Bury ◽  
Rafał Cieślicki ◽  
Krzysztof Towarnicki ◽  
...  
Keyword(s):  
Experimental Research ◽  
Mechanical Efficiency ◽  
Volumetric Efficiency ◽  
Positive Displacement ◽  
Compensation Methods ◽  
Gear Pumps ◽  
Design Solutions ◽  
Materials Used ◽  
Internal Gear

Contemporary gear pumps, although their design has been under development for over four centuries, keep being modernized and improved. The work presents an analysis of design solutions, taking into account their operational features. The analysis included units with internal mesh. Emphasis was put on the problem of ensuring high values of volumetric efficiency by minimizing leakage in the widest possible range of loads while maintaining the highest possible hydraulic and mechanical efficiency of the displacement unit. Increasing the volumetric efficiency of positive displacement pumps is an important factor in the pursuit of increase in working pressures in hydrostatic systems. An important factor in production of pumps is cost of their production, which often leads to possibility of introducing additional modifications in the pump structure. Often changes made to the materials used in construction of pumps, allow reduction in their mass or sensitivity to the action of the transported liquid. The paper indicates the developed and proprietary solutions in this area and presents the results of experimental research.

Study on the Angle of Stationary Crescent for Radial Compensation of Inner Mesh Gear Pumps

2011 ◽  
Vol 317-319 ◽  
pp. 1438-1443
Author(s):  
Jian Zhuo Zhang ◽  
Kang Kang Li ◽  
Meng Gao ◽  
Tian Zi Zhu
Keyword(s):  
High Pressure ◽  
Pressure Distribution ◽  
Volumetric Efficiency ◽  
Hydraulic Pressure ◽  
Working Mechanism ◽  
Outlet Pressure ◽  
Hydraulic Force ◽  
Pressure Area ◽  
Gear Pumps ◽  
Internal Gear

Abstract：The working mechanism of the stationary crescent for radial compensation in the inner mesh gear pumps was studied in this paper. The force of the top and bottom stationary crescent in one hydraulic pressure changing cycle was analysed. The pressure distribution on the top and bottom stationary cressent in different positions and the hydraulic force at the x，y direction were determined.Under the condition of the force of the top and bottom stationary crescent is least and the two stationary crescents stay close to the tooth crest of internal gear and external gear to form radial seal，the angle of the end of the top stationary crescent in the high pressure area and the fixing angle of the seal stick was optimized. Experiment results show that the volumetric efficiency is 0.94 when the outlet pressure reach to 30Mpa, and the oil temperature is less than 55°C, there is no abrasion on the two sationary crescents and the tooth crest.

Measuring the Losses of Hydrostatic Pumps and Motors: A Critical Review of ISO4409:2007

2019 ◽  
Author(s):  
Peter Achten ◽  
Robin Mommers ◽  
Takao Nishiumi ◽  
Hubertus Murrenhoff ◽  
Nariman Sepehri ◽  
...  
Keyword(s):  
Measurement Data ◽  
Mechanical Efficiency ◽  
Energy Conversion Efficiency ◽  
Volumetric Efficiency ◽  
Total Loss ◽  
Loss Analysis ◽  
The Road ◽  
Positive Displacement ◽  
Displacement Pump ◽  
Steady State Performance

Abstract ISO 4409 is the most important international standard for measuring the efficiency of hydraulic pumps and motors, the latest edition being 4409:2007. The standard describes methods for determining the steady-state performance in terms of overall efficiency. It also defines equations for calculating the volumetric efficiency of pumps and motors. The hydro-mechanical efficiency is only defined for motors, not for pumps. This paper analyses the efficiency and losses of pumps and motors in an alternative way. The preference is on loss analysis instead of efficiencies. Especially the effects of the bulk modulus are considered in a different and more inclusive manner. The new methodology results in a higher total loss for motor and a lower total loss for pumps than the current ISO 4409 standard. Furthermore, it results in significant changes of the hydro-mechanical and volumetric losses. The differences between the new methodology and ISO 4409 become larger for high load pressures. The new methodology demands knowledge about the minimum volume of the displacement chamber. The ratio between this volume and the full displacement of a single displacement chamber strongly influences the hydro-mechanical and volumetric losses of the pump or motor. The new methodology is valid for all positive displacement hydrostatic pumps and motors. The volumetric efficiency, as defined in ISO 4409, can still be used as a flow rate factor, but should not be regarded as an energy conversion efficiency. The importance of adopting the proposed methodology is further demonstrated by analyzing and comparing the measurement data about a fixed displacement pump and motor, showing the differences in the loss analysis by means of ISO 4409 and the new equations. The methodology, observations and validation results presented in this paper are significant and can pave the road for improving the current ISO 4409:2007 standard, which would ultimately benefit the industry.

Study on Tooth Profile of Involute Conjugated Internal Gear for High-Pressure Internal Gear Pumps

2011 ◽  
Vol 328-330 ◽  
pp. 186-189 ◽  
Author(s):  
Wei Song ◽  
Hua Zhou
Keyword(s):  
High Pressure ◽  
3D Models ◽  
Tooth Profile ◽  
Volumetric Efficiency ◽  
Flow Pulse ◽  
Wear Life ◽  
Gear Pumps ◽  
Gear Geometry ◽  
Internal Gear

Conjugated internal gear is the key component of high-pressure internal gear pumps, which decides the performance of the pumps, such like volumetric efficiency, capacity of fluid discharge, wear life, flow pulse, vibration and noise. In this paper, a method of generating tooth profiles for conjugated internal gear is presented. Based on gear geometry and meshing theory, the parametric equations of involute conjugated internal gear are derived. With the help of MATLAB and SolidWorks, 3D models of the gear couple are built to evaluate the feasibility of the method.

Light-duty single and multi-shaft boosting and compounding studies with in-cylinder insulation

2020 ◽  
pp. 146808742098058
Author(s):  
Peter Andruskiewicz ◽  
Russell Durrett ◽  
Venkatesh Gopalakrishnan ◽  
Kushal Narayanaswamy ◽  
Paul Najt
Keyword(s):  
Engine Performance ◽  
Volumetric Efficiency ◽  
Expansion Process ◽  
Exhaust Gases ◽  
Positive Displacement ◽  
Brake Power ◽  
Light Duty ◽  
Insight Into

A set of two-cylinder engine concepts utilizing a supercharger and piston- or turbine-compounding were compared to a turbocharged engine modeled with a consistent methodology developed in previous works. In-cylinder insulation was added to each of the engines to evaluate the effects on performance. The goals of this simulation were to utilize energy that otherwise would be bypassed around the turbine side of a turbocharger and redirect it to the crankshaft, as well as to redirect energy that would previously have entered the coolant into the exhaust gases where it could be reclaimed by a second expansion process. Gains in performance and efficiency were thoroughly analyzed to provide insight into the magnitudes and mechanisms responsible. It was found that the second expansion process from exhaust-compounding was able to significantly improve engine performance at moderate to high loads, as well as compensate for the loss in volumetric efficiency that accompanies in-cylinder insulation. The piston-compounded single-shaft DCDE was able to outperform the turbocharged multi-shaft DCDE at mid to high loads, and in maximum brake power due to the low losses in the coupled nature of the second expansion, while the turbine-compounded engine suffers higher losses due to the turbomachinery mismatch with the positive displacement power cylinders.

An Analysis of the Effects Causing an Asymmetric Behavior of the Lateral Lubricating Films of External Spur Gear Machines

2021 ◽  
Author(s):  
Kaeul Lim ◽  
Federico Zappaterra ◽  
Swarnava Mukherjee ◽  
Andrea Vacca
Keyword(s):  
Spur Gear ◽  
Common Assumption ◽  
Simulation Tools ◽  
Positive Displacement ◽  
Asymmetric Behavior ◽  
External Gear Pumps ◽  
Pressure Development ◽  
Gear Pumps ◽  
Set Up ◽  
Lateral Gaps

Abstract The torque efficiency and flow efficiency of positive displacement machines for fluid power applications are determined by the behavior of their internal lubricating interfaces. This aspect has motivated the development of tribological simulation tools for the analysis of these interfaces. The level of details these tools can provide allows explaining some counterintuitive aspects that occur in these interfaces. This paper focuses on a significant example, which is the high asymmetric behavior of the lubricating films occurring in pressure compensated external gear pumps. These units are often designed with a symmetric axial balancing compensation system. Notwithstanding, there are differences between the lateral gaps that can be explained only considering the mutual effects of the pressure development in the film and the material deformation. To study this problem, this paper utilizes the tool Multics-HYGESim developed by the authors’ research team. Two analyses are performed: the first one imposing axial symmetry in the behavior of the gap, which is the common assumption discussed in literature; the second one (referred to as “full configuration”), which holds the asymmetric behavior of the gap. An experimental set-up is used to validate the modeling assumptions based on the measurements of the drain leakage and volumetric efficiency. The main paper findings are on the uneven distribution of these leakages, which indicates an asymmetric behavior of the gap films in the unit.

Meaningful and Physically Consistent Efficiency Definition for Positive Displacement Pumps - Continuation of the Critical Review of ISO 4391 and ISO 4409

2021 ◽  
Author(s):  
Christian Schänzle ◽  
Peter F. Pelz
Keyword(s):  
Critical Review ◽  
Volumetric Efficiency ◽  
Dead Volume ◽  
Specific Enthalpy ◽  
Positive Displacement ◽  
Displacement Pump ◽  
Fluid Properties ◽  
The Common ◽  
Isentropic Efficiency ◽  
The Ideal

Abstract ISO 4391:1984 gives the common efficiency definition for positive displacement machines. ISO 4409:2019 uses this efficiency definition to specify the procedure for efficiency measurements. If the machine conditions do not correspond with an incompressible flow due to operation at high pressure levels, the compressibility of the fluid and the dead volume of a pump must be taken into account. On this point, ISO 4391:1984 is physically inconsistent. Achten et. al. address this issue in their paper at FPMC 2019 presenting a critical review of ISO 4409:2007. They introduce new definitions of the overall efficiency as well as the mechanical-hydraulic efficiency. At the same time, they question the validity of the volumetric efficiency definition. Li and Barkei continue on this issue in their paper at FPMC 2020 and give a new efficiency definition based on the introduction of a new quantity Φ which describes the volume specific enthalpy of the conveyed fluid. The motivation of this paper is to contribute to the ongoing and fruitful discussion. Our approach starts with the most general efficiency definition, namely the isentropic efficiency. Subsequently, we make assumptions concerning the fluid properties with respect to the compressibility of the conveyed fluid. On the basis of the ideal cycle of a positive displacement pump and the p-v diagram, we derive physically consistent and more meaningful representations of the overall, the mechanical-hydraulic and the volumetric efficiency that address the inconsistency of ISO 4391:1984. Furthermore, we compare our findings with the existing results of Achten et. al. and Li and Barkei.

Analysis of Material Punching Including a Rotational Speed of the Projectile

2015 ◽  
Vol 220-221 ◽  
pp. 571-576 ◽  
Author(s):  
Miroslaw Bocian ◽  
Krzysztof Jamroziak ◽  
Mariusz Kosobudzki
Keyword(s):  
Plastic Deformation ◽  
Computer Simulations ◽  
Experimental Research ◽  
Dynamic Load ◽  
Translational Motion ◽  
Viscous Friction ◽  
Perfectly Plastic ◽  
Plastic Yield ◽  
Materials Used ◽  
External Loads

Materials used for the construction of ballistic shields are characterized by a variety of behaviours under the influence of external loads. Ballistic impact (by a bullet) in armour (ballistic shield) is an example of the phenomena that could be considered in the category of a dynamic load caused by the strike of the mass. Computer simulations are commonly used in such situations. It is especially important to adopt a proper model of the behaviour of the material. This paper presents the results obtained by simulating free 3D points and using the application developed by the authors for the purpose of this research. The made calculations include the translational motion and rotary motion of the projectile as well as the stiffness of the material, the damping of the material, friction at the points of contacting surfaces, viscous friction and plastic deformation (the material beyond the plastic yield point is perfectly plastic). The results of simulations were validated with experimental research.

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