Simulation of the characteristics of the water-lubricated journal bearing in twin-screw air compressor

2018 ◽  
Vol 70 (8) ◽  
pp. 1476-1486
Author(s):  
Chuang Wang ◽  
Ziwen Xing ◽  
Xi Pan ◽  
Zhilong He
Keyword(s):  
Surface Roughness ◽  
Journal Bearing ◽  
Design Parameters ◽  
Screw Compressor ◽  
Content Type ◽  
Bending Deformation ◽  
Air Compressor ◽  
Rotating Speed ◽  
Twin Screw ◽  
Lubrication Characteristics

Purpose The well-operating condition of journal bearing is the assurance to keep superior performance of water-lubricated twin-screw compressor. To design the journal bearing more reasonably for this type of compressor, this paper aims to study the effects of rotating speed and design parameters on bearing characteristics, considering surface roughness and bending deformation of the shaft at the same time. Design/methodology/approach The average Reynolds equation considering the effect of surface roughness is adopted and solved by finite difference method and successive over-relaxation method to calculate pressure distribution with real bearing shapes and boundary conditions. The bending deformation of the shaft is calculated using simply supported beam model of variable cross-section. Findings The dynamic lubrication characteristics of four water-lubricated journal bearings in twin-screw air compressor are calculated and analyzed. In addition, the static characteristics of journal bearing including friction coefficient, film thickness ratio distribution and water film pressure distribution are calculated numerically with different rotating speed and design parameters. Moreover, some design principles of water-lubricated bearing for twin-screw compressor are put forward. Originality/value The lubrication characteristics of the water-lubricated journal bearing in twin-screw air compressor are calculated considering surface roughness and bending deformation of the shaft at the same time. The paper’s results may provide design guidelines for journal bearing in this kind of twin-screw compressor.

Effect of surface roughness, viscosity-pressure relationship and elastic deformation on lubrication performance of misaligned journal bearings

2014 ◽  
Vol 66 (3) ◽  
pp. 337-345 ◽  
Author(s):  
Jun Sun ◽  
Xinlong Zhu ◽  
Liang Zhang ◽  
Xianyi Wang ◽  
Chunmei Wang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Elastic Deformation ◽  
Journal Bearing ◽  
Pressure Effect ◽  
Journal Bearings ◽  
Bearing Surface ◽  
Compliance Matrix ◽  
Content Type ◽  
Lubrication Performance ◽  
Lubrication Characteristics

Purpose – Current lubrication analyses of misaligned journal bearings were generally performed under some given preconditions. To make the lubrication analysis closer to the actual situation and usable to the journal bearing design, the purpose of this paper was to calculate the lubrication characteristics of misaligned journal bearings considering the viscosity-pressure effect of the oil, the surface roughness and the elastic deformation of the journal bearing at the same time. Design/methodology/approach – The lubrication of bearings was analyzed using the average Reynolds equation. The deformation of the bearing surface under oil film pressure was calculated by a compliance matrix method. The compliance matrix was established by finite element analysis of the bearing housing. The viscosity-pressure and viscosity–temperature equations were used in the analysis. Findings – The oil viscosity-pressure relationship has a significant effect on the lubrication of misaligned journal bearings. The surface roughness will affect the lubrication of misaligned journal bearings when the eccentricity ratio and angle of journal misalignment are all large. The directional parameter of the surface has an obvious effect on the lubrication of misaligned journal bearings. The deformation of the bearing surface has a remarkable effect on the lubrication of misaligned journal bearings. Originality/value – The lubrication characteristics of misaligned journal bearings were calculated considering the viscosity-pressure effect of the oil, the surface roughness and the elastic deformation of the journal bearing at the same time. The results of this paper are helpful to the design of the bearing.

Investigation of sustainability of lubricated journal bearing under relevant design parameters

2018 ◽  
Vol 70 (4) ◽  
pp. 789-804 ◽  
Author(s):  
M.M. Shahin ◽  
Mohammad Asaduzzaman Chowdhury ◽  
Md. Arefin Kowser ◽  
Uttam Kumar Debnath ◽  
M.H. Monir
Keyword(s):  
Aspect Ratio ◽  
Elastic Strain ◽  
Journal Bearing ◽  
Design Parameters ◽  
Content Type ◽  
Computational Fluid Dynamics Cfd ◽  
Stress Formation ◽  
Bearing Design ◽  
The Stability ◽  
Bearing Friction

Purpose The purposes of the present study are to ensure higher sustainability of journal bearings under different applied loads and to observe bearing performances such as elastic strain, total deformation and stress formation. Design/methodology/approach A journal bearing test rig was used to determine the effect of the applied load on the bearing friction, film thickness, lubricant film pressure, etc. A steady-state analysis was performed to obtain the bearing performance. Findings An efficient aspect ratio (L/D) range was obtained to increase the durability or the stability of the bearing while the bearing is in the working condition by using SAE 5W-30 oil. The results from the study were compared with previous studies in which different types of oil and water, such as Newtonian fluid (NF), magnetorheological fluid (MRF) and nonmagnetorheological fluid (NMRF), were used as the lubricant. To ensure a preferable aspect ratio range (0.25-0.50), a computational fluid dynamics (CFD) analysis was conducted by ANSYS; the results show a lower elastic strain and deformation within the preferable aspect ratio (0.25-0.50) rather than a higher aspect ratio using the SAE 5W-30 oil. Originality/value It is expected that the findings of this study will contribute to the improvement of the bearing design and the bearing lubricating system.

Tribological performance of a surface textured meso scale air bearing

2019 ◽  
Vol 72 (5) ◽  
pp. 599-609
Author(s):  
Nilesh D. Hingawe ◽  
Skylab P. Bhore
Keyword(s):  
Friction Coefficient ◽  
Journal Bearing ◽  
Load Capacity ◽  
Tribological Performance ◽  
Design Parameters ◽  
Content Type ◽  
Thin Film Model ◽  
Maximum Improvement ◽  
Meso Scale ◽  
Texture Design

Purpose The purpose of this study is to improve the tribological performance of meso scale air journal bearing by adopting texture on the bearing surface. Design/methodology/approach The present study is based on numerical analysis. The detailed numerical investigation is carried out using a fluid flow based thin-film model in COMSOL 5.2 software. Findings The influence of texture design parameters: geometry (shape, orientation and slender ratio), and position on the tribological performance of meso scale air journal bearing is investigated. It is found that texture shape has a strong influence on the tribological characteristics such as load capacity and friction coefficient of the bearing. Slender texture improves the load capacity, but it has a negligible effect on the reduction of friction coefficient. In contrast, texture orientation is found to be insignificant for both increasing load capacity and decreasing friction coefficient. Furthermore, the maximum improvement in load capacity is obtained for partially textured bearing, but the minimum friction coefficient is achieved for full texturing. Originality/value The present study investigates the influence of texture design parameters viz geometry (shape, orientation and slender ratio), and position on the tribological performance of meso scale air journal bearing.

Performance and Bearing Load Analysis of a Twin Screw Air Compressor

1999 ◽  
Vol 15 (2) ◽  
pp. 69-78 ◽  
Author(s):  
W. S. Lee ◽  
R. H. Ma ◽  
W.F. Wu ◽  
S.L. Chen ◽  
H.W. Hsia
Keyword(s):  
Measured Data ◽  
Specific Power ◽  
Design Parameters ◽  
Air Compressor ◽  
Operational Conditions ◽  
Discharge Temperature ◽  
Oil Flow ◽  
Twin Screw ◽  
Computer Simulation Program ◽  
Bearing Loads

ABSTRACTTo study the performance and estimate the oscillating bearing loads of a twin screw air compressor, a theoretical model is proposed in this paper. Based on the model, a computer simulation program is developed and effects of different design parameters such as rotor profile, geometric clearance, oil injected position, oil temperature, oil flow rate and other operational conditions are investigated. Output variables such as bearing loads, specific power, compression efficiency, volumetric efficiency, discharge temperature are obtained. Some of the results are then compared with experimentally measured data, and good agreements are found between the simulation results and the measured data.

A review of melt extrusion additive manufacturing processes: II. Materials, dimensional accuracy, and surface roughness

2015 ◽  
Vol 21 (3) ◽  
pp. 250-261 ◽  
Author(s):  
Brian N. Turner ◽  
Scott A Gold
Keyword(s):  
Surface Roughness ◽  
Additive Manufacturing ◽  
Product Design ◽  
Fused Deposition Modeling ◽  
Dimensional Accuracy ◽  
Design Parameters ◽  
Content Type ◽  
Fused Deposition ◽  
Deposition Modeling ◽  
Am Processes

Purpose – The purpose of this paper is to critically review the literature related to dimensional accuracy and surface roughness for fused deposition modeling and similar extrusion-based additive manufacturing or rapid prototyping processes. Design/methodology/approach – A systematic review of the literature was carried out by focusing on the relationship between process and product design parameters and the dimensional and surface properties of finished parts. Methods for evaluating these performance parameters are also reviewed. Findings – Fused deposition modeling® and related processes are the most widely used polymer rapid prototyping processes. For many applications, resolution, dimensional accuracy and surface roughness are among the most important properties in final parts. The influence of feedstock properties and system design on dimensional accuracy and resolution is reviewed. Thermal warping and shrinkage are often major sources of dimensional error in finished parts. This phenomenon is explored along with various approaches for evaluating dimensional accuracy. Product design parameters, in particular, slice height, strongly impact surface roughness. A geometric model for surface roughness is also reviewed. Originality/value – This represents the first review of extrusion AM processes focusing on dimensional accuracy and surface roughness. Understanding and improving relationships between materials, design parameters and the ultimate properties of finished parts will be key to improving extrusion AM processes and expanding their applications.

On hydrodynamic lubrication characteristics of ferrofluid film in a spiral groove mechanical seal

2018 ◽  
Vol 70 (9) ◽  
pp. 1783-1797 ◽  
Author(s):  
Penggao Zhang ◽  
Boqin Gu ◽  
Jianfeng Zhou ◽  
Long Wei
Keyword(s):  
Electromagnetic Field ◽  
Volume Fraction ◽  
Hydrodynamic Lubrication ◽  
Groove Width ◽  
Mechanical Seal ◽  
Spiral Groove ◽  
Content Type ◽  
Rotating Speed ◽  
Lubrication Characteristics ◽  
Spiral Angle

Purpose The purpose of this study is to investigate the hydrodynamic lubrication characteristics of ferrofluid film for spiral groove mechanical seal in external electromagnetic field and to analyze the effects of the volume fraction of ferrofluid, parameters of the electromagnetic field, operating parameters and geometrical parameters of mechanical seal on the characteristics of ferrofluid film. Design/methodology/approach The relationship between the ferrofluid viscosity and the intensity of external electromagnetic field was established. Based on the Muijderman narrow groove theory, the pressure distribution was calculated with the trial method by trapezoid formula. Findings It was found that pressure, average viscosity, average density and opening force of ferrofluid between end faces increase with the increase in intensity of current, volume fraction of ferrofluid, rotating speed, pressure differential and spiral angle; decrease with the increase in temperature; and increase at first and then decrease with the increase in the ratio of groove width to weir and the groove length. All of them reach the maximum value when the ratio of width of groove to weir is 0.7 and the ratio of groove length is 0.6. Leakage of ferrofluid increases with an increase in intensity of current, volume fraction of ferrofluid, rotating speed, pressure differential, spiral angle and ratio of groove length; decreases with an increase in temperature; and increases at first and then decreases with the increase in the ratio of groove width to weir. The tendencies of characteristics of silicone oil are consistent with those of ferrofluid, and the characteristics of silicone oil are smaller than those of ferrofluid under the same condition. Originality/value The volume fraction of ferrofluid, rotating speed, spiral angle, ratio of groove width to weir, groove length and temperature have a significant influence on the characteristics of ferrofluid film; however, intensity of current and the pressure differential have slight influence on the characteristics of ferrofluid film. An analytical method for analyzing hydrodynamic lubrication characteristics of ferrofluid film in a spiral groove mechanical seal was proposed based on the Muijderman narrow groove theory.

scholarly journals Effect of the axial movement of misaligned journal on the performance of hydrodynamic lubrication journal bearing with rough surface

2019 ◽  
Vol 20 (4) ◽  
pp. 402 ◽  
Author(s):  
Biao Li ◽  
Jun Sun ◽  
Shaoyu Zhu ◽  
Yangyang Fu ◽  
Xiaoyong Zhao ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Topography ◽  
Reynolds Equation ◽  
Working Condition ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Axial Movement ◽  
Combined Action ◽  
Lubrication Characteristics ◽  
Bearing System

Generally, the movement of journal along the direction of bearing axis under the combined action of various factors is neglected in the lubrication study of bearing, which is quite different from the actual working condition of bearing in the shaft-bearing system. In this paper, with a comprehensive consideration of the axial movement of journal, the surface topography of journal and bearing and the misalignment of journal, a new model about the hydrodynamic lubrication of misaligned journal bearing is established based on the average Reynolds equation. Considering the effect of the axial movement of misaligned journal, the lubrication characteristics parameters of rough journal bearing is presented and mainly discussed. The results show that the axial movement of misaligned journal has a distinct effect on the bearing lubrication characteristics. The influence of the axial movement of misaligned journal on the bearing lubrication characteristics is slightly reduced when considering the surface roughness.

Analytical model of a particular type of positive displacement blower

1999 ◽  
Vol 213 (5) ◽  
pp. 517-526 ◽  
Author(s):  
G Mimmi ◽  
P Pennacchi
Keyword(s):  
Mathematical Model ◽  
Analytical Model ◽  
Design Parameters ◽  
Rotary Compressor ◽  
Screw Compressor ◽  
Positive Displacement ◽  
Compressed Gas ◽  
Twin Screw

Many papers exist in the literature that deal with the twin-screw compressor. This usually has two different rotors, a male and a female, and is commonly used to produce compressed gas for industrial uses. However, a different type of positive displacement rotary compressor with two screws is sometimes used, one of its typical applications being in car engine supercharging. The present paper deals with the latter type, which is defined as a two-screw blower. This blower has two identical helical rotors, each with three lobes. The kinematics and the geometry of the rotors are analysed here, and a complete mathematical model for the rotor is defined. Moreover, different possible shapes of the rotors, depending on the design parameters, are analysed and the limitations in the choice of the design parameters are presented. Finally, an analysis of the theoretical specific slipping of the rotors is presented, showing which zones of the profile are the most stressed. This model will be useful for further studies on rotor pressure loads and blower dynamics.

Parameters Selection and Profile Calculation for Screw Rotor of Twin Screw Air Compressor

2017 ◽  
Vol 873 ◽  
pp. 308-313
Author(s):  
Jian Hua Qin ◽  
Wen Li ◽  
Cheng Yun Deng
Keyword(s):  
Smooth Curve ◽  
Machining Process ◽  
Tooth Surface ◽  
Design Parameters ◽  
Air Compressor ◽  
Rotor Profile ◽  
Parameters Selection ◽  
Twin Screw ◽  
Screw Rotor ◽  
Set Up

Screw rotor is a vital factor affecting the working efficiency of twin screw air compressor. Therefore, a type of twin screw air compressor in coal mine production process is taken as the research object. Firstly, the working principle and process of female and male rotor was introduced and analyzed. Then, according to the principle of parameter selection of the female and male rotor, the relevant design parameters of the female and male rotor are given. Finally, the vector equation and the tooth surface equation of the segmented line are deduced and established respectively for the end face profile and end face tooth surface of the rotor, the area and volume of the tooth are also calculated. The equation of the tooth surface is set up by rotation of rotor’s tooth direction, the inter-tooth area is composed of multi-section smooth curve and the top arc connected to form a circle, which can be obtained by means of analytical method. In order to better meet the requirements of the machining process, it is necessary to coordinate the female and male rotor profile on the coordinate axis when the end face of the rotor is non-symmetrical. This paper provides an important reference for selecting parameters of the rotor of the female and male and calculation of rotor profile.

Lubrication characteristics of the worn slipper in the slipper-swashplate pair

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Haiji Wang ◽  
Guanglin Shi
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Design Methodology ◽  
Reynolds Equation ◽  
Thickness Distribution ◽  
Operating Conditions ◽  
Test Rig ◽  
Content Type ◽  
Oil Film ◽  
Lubrication Characteristics

Purpose This paper proposes the lubrication characteristics of the worn slipper in the slipper–swashplate pair. The mathematical analysis of lubrication characteristics of slipper with the measured surface roughness distribution is introduced. Based on the results from the test rig, it carries out the result compassion in different operating conditions. Design/methodology/approach This paper introduces the measured surface roughness distribution of new and used slippers and generates the oil film thickness distribution with it. An average flow Reynolds equation of the pressure distribution is introduced too. The experimental results are carried out on a novel adjustable oil film thickness test rig. Findings The surface roughness of the worn slipper enlarges the reacting force and torque only if the oil film thickness is small. When the ratio of oil film thickness to the root mean square of surface roughness is much smaller than 3, the influence of it on torque is obvious. Originality/value Different surface roughness of worn slipper proposed in this paper has an influence on the lubrication characteristics. As the slipper is worn after a period of use, the changed lubrication characteristics should be considered in the slipper design.

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