Operation Parameters' Effect on Gaseous Bubbles in Lubricant of Groove Textured Journal Bearing

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
F. M. Meng ◽  
L. Zhang ◽  
T. Long
Keyword(s):  
Journal Bearing ◽  
Computer Code ◽  
Diameter Ratio ◽  
Inlet Temperature ◽  
Bubble Behavior ◽  
Collapse Pressure ◽  
Shaft System ◽  
Operation Parameter ◽  
Gaseous Bubble ◽  
Gaseous Bubbles

Operation parameter influences on the behavior of the gaseous bubble in the lubricant for a groove textured journal bearing are studied under the consideration of the thermal effect of the bearing–shaft system. The influence is analyzed by simultaneously solving Rayleigh–Plesset (RP), energy, and Reynolds equations. The computer code for the analyzing the bubble behavior is validated. Numerical results show that appropriately increasing the width–diameter ratio of the bearing and rotational speed of the shaft, or decreasing the applied load and inlet temperature of the lubricant, can decrease the maximum radius, collapse pressure, and temperature of the bubble.

Effect of Groove Textures on the Performances of Gaseous Bubble in the Lubricant of Journal Bearing

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
F. M. Meng ◽  
L. Zhang ◽  
T. Long
Keyword(s):  
Journal Bearing ◽  
Bubble Radius ◽  
Groove Depth ◽  
Cycle Period ◽  
Collapse Pressure ◽  
Bubble Pressure ◽  
Collapse Temperature ◽  
Gaseous Bubble ◽  
Length Width ◽  
Gaseous Bubbles

Effects of groove textures on the performances for gaseous bubbles in the lubricant used for a textured journal bearing is studied under the consideration of thermal effect of lubricant. The Reynolds, energy, and Rayleigh–Plesset (RP) equations are solved simultaneously for simulating the behavior of the bubble. Numerical results show that the gaseous bubble radius shows a nonlinearly oscillation in a full cycle period, and high bubble pressure and temperature appear when the bubble collapses. Moreover, appropriately choosing groove length, width, or interval can reduce the maximum radius, collapse pressure, and collapse temperature of the bubble. There exists a critical groove depth minimizing the bubble pressure and temperature.

scholarly journals Analysis of misaligned journal bearing lubrication performance considering the effect of lubricant couple stress and shear thinning

2021 ◽  
Vol 37 ◽  
pp. 282-290
Author(s):  
Junchao Zhu ◽  
Haiyu Qian ◽  
Huabing Wen ◽  
Liangyan Zheng ◽  
Hanhua Zhu
Keyword(s):  
Film Thickness ◽  
Couple Stress ◽  
Journal Bearing ◽  
Shear Thinning ◽  
Inlet Temperature ◽  
Stress Effect ◽  
Misalignment Angle ◽  
Oil Film ◽  
Stress Coefficient ◽  
Lubrication Performance

ABSTRACT This paper investigates journal bearings, and builds a lubrication model taking into account misalignment, the lubricant couple stress effect and shear thinning. In order to explore the sensitivity of couple stress fluid lubrication performance to oil film thickness, we introduce the critical oil film thickness coefficient. The results show that the sensitivity increases with the increase of the couple stress coefficient, and it is highest in the area of minimum oil film thickness. Compared with a parallel journal, increases in the misalignment angle strengthen the effect of couple stress. Shear thinning also plays an important role in bearing lubrication performance. For a low oil inlet temperature, the effect of shear thinning increases with the increase of the couple stress parameter. For a high oil inlet temperature, the influence is negligible. An increase in the misalignment angle will not further enhance the effect of shear thinning.

STATIC CHARACTERISTICS OF OFFSET 8-LOBE JOURNAL BEARINGS

Tribologia ◽  
2021 ◽  
Vol 295 (1) ◽  
pp. 39-51
Author(s):  
Stanisław Strzelecki
Keyword(s):  
Laminar Flow ◽  
Equilibrium Position ◽  
Iterative Procedure ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Diameter Ratio ◽  
Static Characteristics ◽  
Oil Film ◽  
Cooling Conditions ◽  
Grinding Machines

The 8-lobe journal bearings have found application in the bearing systems of spindles of grinding machines. The design of bearings and the large number of lobes and oil grooves assures good cooling conditions of bearing. These bearings can be manufactured as the bearings with cylindrical, non-continuous operating surfaces separated by six lubricating grooves, bearings with the pericycloidal shape of the bearing bore, and as offset journal bearing. This paper presents the results of the computation of static characteristics of an offset 8-lobe journal bearing operating under the conditions of an aligned axis of journal and bush, adiabatic oil film, and at the static equilibrium position of journal. Different values of bearing length to diameter ratio, relative clearance, and lobe relative clearance were assumed. Reynolds' energy and viscosity equations were solved by means of an iterative procedure. Adiabatic oil film, laminar flow in the bearing gap, and aligned orientation of journal in the bearing were considered.

A Parametric Analysis for Optimal Selection of a Gas Turbine Cogeneration System

2004 ◽  
Author(s):  
K. Sarabchi ◽  
A. Ansari
Keyword(s):  
Gas Turbine ◽  
Pressure Ratio ◽  
Computer Code ◽  
Primary Energy ◽  
Inlet Temperature ◽  
Fuel Cost ◽  
Energy Usage ◽  
Turbine Inlet Temperature ◽  
Cogeneration System ◽  
Selection Of

Cogeneration is a simultaneous production of heat and electricity in a single plant using the same primary energy. Usage of a cogeneration system leads to fuel energy saving as well as air pollution reduction. A gas turbine cogeneration plant (GTCP) has found many applications in industries and institutions. Although fuel cost is usually reduced in a cogeneration system but the selection of a system for a given site optimally involves detailed thermodynamic and economical investigations. In this paper the performance of a GTCP was investigated and an approach was developed to determine the optimum size of the plant to meet the electricity and heat demands of a given site. A computer code, based on this approach, was developed and it can also be used to examine the effect of key parameters like pressure ratio, turbine inlet temperature, utilization period, and fuel cost on the economics of GTCP.

Thermo-hydrodynamic simulation study of twin-groove elliptical (two-lobe) journal bearing of steam turbine with experimental investigations

2020 ◽  
pp. 135065012097379
Author(s):  
Navin Kumar ◽  
Akash Shukla ◽  
Sanjay Bansal ◽  
Chandra B Khatri ◽  
Gannath D Thakre ◽  
...  
Keyword(s):  
Journal Bearing ◽  
Operating Conditions ◽  
Experimental Investigations ◽  
Inlet Temperature ◽  
Steam Turbines ◽  
Hydrodynamic Simulation ◽  
Load Carrying ◽  
Temperature Load ◽  
Fully Automatic ◽  
Hydrodynamic Journal Bearing

The present paper reports an experimental and theoretical investigation on performance behaviour of twin-groove elliptical (two-lobe) white metal hydrodynamic journal bearing used in steam turbines. The experiments are performed on a fully automatic journal bearing test rig with provisions to various operating conditions (i.e. load, speed, and lubricant temperature). The performance behaviour in terms of coefficient of friction, lubricant inlet temperature, load carrying capacity, journal displacement, weight loss etc. has been presented. In addition to this, numerical investigations have also been performed with the numerical solution of governing Reynolds equation using FEM (finite element method) technique and Jakobsson-Floberg-Olsson (JFO) boundary condition. The experimentally obtained and theoretical results have been correlated.

The Effects of Oil Supply Pressure at different Groove Position on Temperature and Pressure Profile in Journal Bearing

2013 ◽  
Vol 66 (3) ◽  
Author(s):  
Mohamad Ali Ahmad ◽  
Salmiah Kasolang ◽  
R. S. Dwyer-Joyce ◽  
Aidah Jumahat
Keyword(s):  
Journal Bearing ◽  
Pressure Profile ◽  
Diameter Ratio ◽  
Radial Load ◽  
Oil Supply ◽  
Supply Pressure ◽  
Pressure Profiles ◽  
Hydrodynamic Journal Bearing ◽  
Temperature And Pressure ◽  
Length To Diameter Ratio

The effects of oil supply pressure on the temperature and pressure at different groove locations on a hydrodynamic journal bearing were investigated. A journal with a diameter of 100 mm and a ½ length-to-diameter ratio was used. The supply pressure was set to 0.2, 0.5, and 0.7 MPa at seven different groove locations, namely, -45°, -30°, -15°, 0°, +15°, +30°, and +45°. Temperature and pressure profiles were measured at speed values of 300, 500, and 800 rpm with 10 kN radial load. The results show that the change in oil supply pressure simultaneously reduced the temperature and increased the pressure profile.

scholarly journals Thermal Turbulent Flow in Leading Edge Grooved and Conventional Tilting Pad Journal Bearing Segments—A Comparative Study

Lubricants ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 97 ◽  
Author(s):  
Philip Croné ◽  
Andreas Almqvist ◽  
Roland Larsson
Keyword(s):  
Comparative Study ◽  
Journal Bearing ◽  
Flow Characteristics ◽  
Leading Edge ◽  
Inlet Temperature ◽  
Average Value ◽  
Tilting Pad ◽  
Sst Turbulence Model ◽  
Effective Boundary Condition ◽  
Tilting Pad Journal Bearing

A comparative study between a conventional- and leading edge grooved (LEG) tilting pad journal bearing (TPJB) segment is performed. The developed model uses the Shear Stress Transport (SST) turbulence model, coupled with the energy equation and a partial differential equation for the fluid domain mesh displacement to predict the thermal flow characteristics. Instead of using an effective boundary condition to determine the inlet temperature of the LEG pad and excluding the additional LEG portion, as is common practice, the whole geometry of the LEG is modeled. Several sizes of the LEG portion is investigated and it is shown to have quite a small influence on pressure, temperature, film thickness and turbulence intensity. Moreover, the results also show that the conventional pad gives rise to higher levels of turbulence in the mid plane compared to its LEG counterpart, while the latter has a marginally higher value of turbulence when the volume average value is computed. The maximum value of turbulence is however present in the conventional model.

Optimization of Clearance in a Squeeze-Film Journal Bearing

1971 ◽  
Vol 93 (2) ◽  
pp. 246-251
Author(s):  
C. L. Strodtman
Keyword(s):  
Numerical Methods ◽  
Small Parameter ◽  
Shape Factor ◽  
Journal Bearing ◽  
Diameter Ratio ◽  
Parameter Analysis ◽  
Squeeze Film ◽  
Clearance Ratio ◽  
Proper Selection ◽  
Selection Of

It is shown that a squeeze-film journal bearing supporting a mass completely contained within the bearing can be designed with the optimum value of minimum clearance by proper selection of the drive amplitude to nominal clearance ratio, the length to diameter ratio, and the shape factor of the excursion. Both a small parameter and an augmented, small parameter analysis are given. In the latter case, numerical methods are employed to solve the resulting equations. The results of the analysis are illustrated in application to an accelerometer design.

The Characteristics of a Statically Loaded Journal Bearing with Superlaminar Flow

1980 ◽  
Vol 22 (2) ◽  
pp. 79-94 ◽  
Author(s):  
R. E. Hinton ◽  
J. B. Roberts
Keyword(s):  
Friction Factor ◽  
Journal Bearing ◽  
Load Capacity ◽  
Reynolds Numbers ◽  
Diameter Ratio ◽  
Experimental Results ◽  
Empirical Theory ◽  
Clearance Ratio ◽  
Friction Factors ◽  
Theoretical Predictions

Experimental results are presented, relating to the friction factor, load capacity and attitude angle, for a plain, cylindrical journal bearing with a central, circumferential inlet groove. The length to diameter ratio of the journal bearing was 1/3 and the clearance ratio was 0.011. By the use of various lubricants, including water, Reynolds numbers ranging from 40 to 50 000 were attained. Comparisons with various theoretical predictions are given. It is shown that a simple, empirical theory, which incorporates measured friction factors, gives better agreement with the experimental load capacity results than previous theories.

scholarly journals Rotordynamics analysis of solar hybrid microturbine for concentrated solar power

2020 ◽  
Vol 11 (1) ◽  
pp. 38
Author(s):  
Maulana Arifin
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Direct Normal Irradiance ◽  
Linear Vibrations ◽  
Parabolic Dish ◽  
Design Speed ◽  
Rotor Assembly ◽  
Tip Displacement

Microturbine based on a parabolic dish solar concentrator runs at high speed and has large amplitudes of subsynchronous turbo-shaft motion due to the direct normal irradiance (DNI) fluctuation in daily operation. A detailed rotordynamics model coupled to a full fluid film radial or journal bearing model needs to be addressed for increasing performance and to ensure safe operating conditions. The present paper delivers predictions of rotor tip displacement in the microturbine rotor assembly supported by a journal bearing under non-linear vibrations. The rotor assembly operates at 72 krpm on the design speed and delivers a 40 kW power output with the turbine inlet temperature is about 950 °C. The turbo-shaft oil temperature range is between 50 °C to 90 °C. The vibrations on the tip radial compressor and turbine were presented and evaluated in the commercial software GT-Suite environment. The microturbine rotors assembly model shows good results in predicting maximum tip displacement at the rotors with respect to the frequency and time domain.

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