A Thermohydrodynamic Analysis of the Self-Lubricating Bearings Applied in Gear Pumps Using Computational Fluid Dynamics Method

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Jintao Mo ◽  
Chaohua Gu ◽  
Xiaohong Pan ◽  
Shuiying Zheng ◽  
Guangyao Ying
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Pressure Profile ◽  
The Self ◽  
Gear Pump ◽  
Hydrodynamic Bearing ◽  
Whirling Motion ◽  
Gear Pumps ◽  
Axial Clearance ◽  
Internal Gear

The transient simulation of the journal bearing temperature in the internal gear pumps is hard due to the complicated shaft motion caused by the complicated loads. In this paper, a thermohydrodynamic analysis method, based on dynamic mesh techniques, is presented with the application of the general computational fluid dynamics (CFD) code fluent. This method can simulate the complex whirling orbit induced temperature variation in internal gear pumps and has taken into account the conduction in the rotating and orbiting rotor of a hydrodynamic bearing. A test rig has been built according to the structure of an internal gear pump to carry out the validation. The results show that the model is reliable. The relationship between bearing temperature, leakage, and axial clearance in the internal gear pump has been studied. It is found that the bearing temperature will decrease slightly, while the leakage increases heavily with larger axial clearance. A thermohydrodynamic analysis of the self-lubricating bearing in the internal gear pump has been done based on this method. The results show that the pressure profile changes regularly with the whirling motion of the journal, while the whirling motion has little effect on the distribution of the temperature. Besides, the increase of the whirling radius will result in the decrease of the pressure profile and the increase of the temperature profile.

Efficiency limits of fans

2019 ◽  
Vol 234 (5) ◽  
pp. 739-748
Author(s):  
Konrad Bamberger ◽  
Thomas Carolus
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Reynolds Number ◽  
Geometrical Parameter ◽  
The Self ◽  
Complex Geometries ◽  
Relevant Parameter ◽  
Optimization Scheme ◽  
Loss Models ◽  
Definition Of

The purpose of this work is to identify upper efficiency limits of industrial fans such as axial rotor-only fans, axial with guide vanes, centrifugal rotor-only and centrifugal with volute. The efficiency limit is always a function of the class, the design point within the class and the definition of efficiency (total-to-static and total-to-total). The characteristic Reynolds number is another relevant parameter. First, based on analytical and empirical loss models, a theoretical efficiency limit is estimated. A set of idealizing assumptions in the loss models yields efficiencies which are assumed to be an insuperable limit but may be unrealistically high. Second, more realistic efficiency limits are estimated using a computational fluid dynamics-based optimization scheme, seeking for the best designs and hence the maximum achievable efficiencies in all classes. Given the self-imposed constraints in the geometrical parameter space considered, the thus-obtained practical efficiency limits can only be exceeded by admitting more complex geometries of the fans.

scholarly journals Determination and Fire Analysis of Gob Characteristics Using CFD

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5274
Author(s):  
Florencio Fernández-Alaiz ◽  
Ana Maria Castañón ◽  
Fernando Gómez-Fernández ◽  
Antonio Bernardo-Sánchez ◽  
Marc Bascompta
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Experimental Tests ◽  
The Self ◽  
Time Dependent ◽  
Scale Analysis ◽  
Dynamics Modelling ◽  
Gob Area ◽  
Time Dependent Analysis ◽  
Waste Coal

A laboratory-scale analysis using coal from an underground mine was carried out, emulating a mixture from the gob area in an actual mine, consisting of waste, coal, and free space for the flow of air. Experimental tests and computational fluid dynamics modelling were done to define and verify the behavior of the collapsed region in a time-dependent analysis. In addition, the characteristics of coal were defined, regarding the self-combustion, combustion rate, and pollutants generated in each stage of the fire. The results achieved are useful for determining the behavior of the collapsed area in full-scale conditions and to provide valuable information to study different scenarios of a potential fire in a real sublevel coal mine regarding how the heat is spread in the gob and how pollutants are generated.

Numerical Simulation of the Gear Flowmeter Reveal Based on Pumplinx

2014 ◽  
Vol 687-691 ◽  
pp. 679-683 ◽  
Author(s):  
Jun Zhang ◽  
Yong Wu ◽  
Hong Mei Tang ◽  
Chun Ren Tang ◽  
Xian Hua Li
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Numerical Analysis ◽  
Oil Spill ◽  
Practical Work ◽  
Measuring Accuracy ◽  
Internal Gear

The oil spill will directly affect the measuring accuracy of the gear flowmeter, so use the computational fluid dynamics software to calculate the leakage regulation of the internal gear flowmeter is one of the important things. Based on Pumplinx, when the end clearances of the gear flowmeter were 0um, 10um, 20um, 30um, 40um and 50um, the corresponding numerical analysis of spillage was carried out. From the results of numerical analysis, with the increase of the end clearance, the leakage amplification will also increase. In practical work, we should control the end clearance of gear flowmeter strictly while the gear works normally.

The use of genetic algorithm and self-updating artificial neural network for the inverse design of cabin environment

2016 ◽  
Vol 26 (3) ◽  
pp. 347-354 ◽  
Author(s):  
Tian-hu Zhang ◽  
Xue-yi You
Keyword(s):  
Neural Network ◽  
Fluid Dynamics ◽  
Genetic Algorithm ◽  
Computational Fluid Dynamics ◽  
Artificial Neural Network ◽  
Computational Cost ◽  
The Self ◽  
Inverse Design ◽  
Artificial Neural ◽  
The Impact

The inverse process of computational fluid dynamics was used to explore the expected indoor environment with the preset objectives. An inverse design method integrating genetic algorithm and self-updating artificial neural network is presented. To reduce the computational cost and eliminate the impact of prediction error of artificial neural network, a self-updating artificial neural network is proposed to realize the self-adaption of computational fluid dynamics database, where all the design objectives of solutions are obtained by computational fluid dynamics instead of artificial neural network. The proposed method was applied to the inverse design of an MD-82 aircraft cabin. The result shows that the performance of artificial neural network is improved with the increase of computational fluid dynamics database. When the number of computational fluid dynamics cases is more than 80, the success rate of artificial neural network increases to more than 40%. Comparing to genetic algorithm and computational fluid dynamics, the proposed hybrid method reduces about 53% of the computational cost. The pseudo solutions are avoided when the self-updating artificial neural network is adopted. In addition, the number of computational fluid dynamics cases is determined automatically, and the requirement of human adjustment is avoided.

Eulerian/Eulerian CFD Simulation of a Cold Flowing FCC Riser

2003 ◽  
Vol 1 (1) ◽  
Author(s):  
Kim G Hansen ◽  
Claus H Ibsen ◽  
Tron Solberg ◽  
Bjørn H Hjertager
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Mass Flux ◽  
International Workshop ◽  
Particle Diameter ◽  
Pressure Profile ◽  
Dynamics Simulation ◽  
Scale Model ◽  
Parameter Study ◽  
Experimental Findings

A computational fluid dynamics simulation, CFD, of a cold flowing riser fluidized with FCC catalysts has been performed. The computations are performed using a 3D multiphase computational fluid dynamics code with a Eulerian description of both gas and particle phase. The turbulent motion of the particulate phase is modelled using the kinetic theory for granular flow, and the gas phase turbulence is modelled using a Sub-Grid-Scale model. The complex inlet geometry is approximated using multiple inlet patches. The results were submitted to a blind-test in connection to the 10th international workshop on two-phase flow prediction held in Merseburg, Germany, 2002. The results are validated against experimental findings of particle mass flux across the riser and pressure profile along the riser. The calculations show good agreement with experimental findings of both mass flux and pressure profile, but further improvements are proposed and investigated. A parameter study shows that mesh refinement, choice of particle diameter and choice of drag model are crucial when simulating FCC riser flow.

Design of Rotor for Internal Gear Pump Using Cycloid and Circular-Arc Curves

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
T. H. Choi ◽  
M. S. Kim ◽  
G. S. Lee ◽  
S. Y. Jung ◽  
J. H. Bae ◽  
...  
Keyword(s):  
Flow Rate ◽  
Superior Performance ◽  
Correction Coefficient ◽  
Gear Pump ◽  
Circular Arc ◽  
Limit Value ◽  
Outer Rotor ◽  
Gear Pumps ◽  
Internal Fluid Flow ◽  
Internal Gear

In the case of internal gear pumps, the eccentricity of the outer rotor, which resembles a circular lobe, must be limited to a certain value in order to avoid the formation of cusps and loops; furthermore, the tip width of the inner rotor, which has a hypocycloid curve and an epicycloid curve, should not be allowed to exceed the limit value. In this study, we suggest that the tip width of the inner rotor be controlled by inserting a circular-arc curve between the hypocycloid and epicycloid curves. We also suggest that the outer rotor be designed using the closed-form equation for the inner rotor and the width correction coefficient. Thus, it is possible to design a gerotor for which there is no upper limit on the eccentricity, as in this case, undercut is prevented and there is no restriction on the tip width. We also develop an automated program for rotor design and calculation of the flow rate and flow rate irregularity. We demonstrate the superior performance of the gerotor developed in this study by analyzing the internal fluid flow using a commercial computational fluid dynamics (CFD)-code.

Numerical analysis of the lubricating gap between the gear shaft and the journal bearing in water hydraulic internal gear pumps

2017 ◽  
Vol 232 (12) ◽  
pp. 2297-2314 ◽  
Author(s):  
Ruilong Du ◽  
Yinglong Chen ◽  
Hua Zhou
Keyword(s):  
Journal Bearing ◽  
Radial Force ◽  
Gear Pump ◽  
Film Pressure ◽  
Proposed Model ◽  
Gear Pumps ◽  
Water Hydraulic ◽  
Film Characteristics ◽  
Internal Gear ◽  
Shaft Journal

Water hydraulics has drawn considerable attention in recent years for its environmental friendliness. This paper presents a numerical model for analysing the lubricating gap between the gear shaft and the journal bearing in water hydraulic internal gear pumps. The model consists of two parts: the gear part that addresses the radial force on the gear shaft and the film part that addresses the film characteristics of the gear shaft/journal bearing interface. The radial force is obtained by summing the fluid pressure around the gear circumference and the meshing force of the gear pair. The film characteristics are analysed by an elastohydrodynamic model that involves the evaluation of the film geometry, the film pressure, and the elastic deformation of the gear shaft/journal bearing interface. The radial force evaluated by the gear part is balanced by the film pressure evaluated by the film part. The gear part is validated by experiments on an oil internal gear pump from the aspect of the outlet pressure ripple, and the film part is validated by comparison with the results from other research groups. The proposed model allows the evaluation of radial micro-motion as well as the eccentric positions of the gear shaft. In addition, the influence of film deformation is further discussed, suggesting that the maximum film deformation should be maintained under 1.3 times the minimum film height. The proposed model can be used as a tool for design optimization of the water-lubricated journal bearing in water hydraulic internal gear pumps.

Efficiency-Driven Design Methodology of Gerotor Hydraulic Units

2019 ◽  
Vol 142 (6) ◽  
Author(s):  
Federico Tessari ◽  
Renato Galluzzi ◽  
Nicola Amati
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Aspect Ratio ◽  
Design Methodology ◽  
High Efficiency ◽  
Design Method ◽  
Hydraulic Devices ◽  
Dynamics Models ◽  
Internal Gear

Abstract Gerotor machines are internal gear hydraulic devices that present numerous performance benefits with respect to other topologies. For this reason, they find their application in high-efficiency mechatronic devices, such as electro-hydrostatic actuators. When designing gerotor machines either as a motor or pump, there are numerous parameters to choose, with different influences on the mechanical and volumetric efficiency behavior. Some of these aspects have been addressed in previous research works, while other important features like the tooth aspect ratio have been partially or completely neglected. Hence, it is the goal of this paper to present a methodology, as linear and generic as possible, to tackle the design of gerotor units. The proposed design method is numerically validated through a case study, where dedicated computational fluid dynamics models are used to assess the performance of the prototype.

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