scholarly journals Analysis of Oil-Air Two-Phase Flow Characteristics inside a Ball Bearing with Under-Race Lubrication

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1223
Author(s):  
Heyun Bao ◽  
Xiaonan Hou ◽  
Fengxia Lu
Keyword(s):  
Ball Bearing ◽  
Two Phase Flow ◽  
Volume Fraction ◽  
Flow Characteristics ◽  
Lubricating Oil ◽  
Phase Flow ◽  
Two Phase ◽  
Inlet Velocity ◽  
Oil Supply ◽  
Circumferential Distribution

Under-race lubrication can increase the amount of lubricating oil entering a bearing and greatly improve lubrication and cooling effects. The oil-air two-phase flow characteristics inside a ball bearing with under-race lubrication play a key role in lubrication and cooling performance. The motions of ball bearing subassemblies are complicated. Ball spin affects the oil volume fraction. In this paper, the coupled level set volume of fluid (CLSVOF) method is used to track the oil-air two-phase flow inside the ball bearing with under-race lubrication. The influence of various factors on the oil volume fraction inside the ball bearing with under-race lubrication is investigated, particularly rotating speeds, inlet velocity and the size of oil supply apertures under the inner ring. The influence of the ball spinning is analyzed separately. The result demonstrates that, on account of the centrifugal force, lubricating oil is located more on the outer ring raceway at rotational speeds of 5000 r/min, 10,000 r/min, 15,000 r/min and 20,000 r/min. The oil volume fraction inside the bearing gradually increases at an oil inlet velocity of 5 m/s, 10 m/s and 15 m/s. The circumferential distribution of oil is also similar. As the diameter of the oil supply aperture increases from 1.5 mm to 2 mm, the oil volume fraction increases inside the ball bearing. However, the oil volume fraction slightly decreases from 2 mm to 2.5 mm of oil supply aperture diameter. Ball spin does not affect the circumferential distribution trend of the lubricating oil, but slightly reduces the oil volume fraction. Furthermore, ball spin causes the surface fluid to rotate around its rotation axis and increases the speed.

Analysis of temperature field and convection heat transfer of oil-air two-phase flow for ball bearing with under-race lubrication

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Heyun Bao ◽  
Xiaonan Hou ◽  
Xin Tang ◽  
Fengxia Lu
Keyword(s):  
Heat Transfer ◽  
Ball Bearing ◽  
Two Phase Flow ◽  
Volume Fraction ◽  
Convection Heat Transfer ◽  
Lubricating Oil ◽  
Phase Flow ◽  
Convection Heat ◽  
Two Phase ◽  
Content Type

Purpose Under-race lubrication can increase the amount of lubricating oil entering a bearing and greatly improve lubrication and cooling effects. The oil-air two-phase flow and heat transfer characteristics inside a ball bearing with under-race lubrication play a key role in lubrication and cooling performance. The purpose of this paper is to study these two characteristics, and then provide guidance for lubrication and heat dissipation of bearing with under-race lubrication. Design/methodology/approach In this paper, a simplified three-dimension heat transfer model of ball bearing with under-race lubrication is established; the coupled level set volume of fluid method is used to track the oil-air two-phase flow, and the Palmgren method is used to calculate the heat generation. The influence of rotation speed and inlet velocity on oil volume fraction, temperature and convection heat transfer is investigated. A temperature test for under-race lubrication is carried out. Findings Because of the centrifugal force, lubricating oil is located more on the outer ring raceway. As the rotation speed decreases and the inlet velocity increases, the oil volume fraction increases and the temperature decreases. Furthermore, the area with high oil volume fraction has a large convection heat transfer coefficient and low temperature. The error between the simulation temperature and the test temperature is within 10%. Originality/value The research on the temperature field and convection heat transfer characteristics of under-race lubrication ball bearings at different rotation speeds and inlet velocities is rarely involved.

scholarly journals Two-Way Coupling Simulation of Solid-Liquid Two-Phase Flow and Wear Experiments in a Slurry Pump

2022 ◽  
Vol 10 (1) ◽  
pp. 57
Author(s):  
Lei Jiang ◽  
Ling Bai ◽  
Peng Xue ◽  
Guangjie Peng ◽  
Ling Zhou
Keyword(s):  
Two Phase Flow ◽  
Volume Fraction ◽  
Volume Flow Rate ◽  
Pure Water ◽  
Solid Volume Fraction ◽  
Flow Characteristics ◽  
Operating Conditions ◽  
Phase Flow ◽  
Two Phase ◽  
Solid Liquid

The slurry pump is one of the most important pieces of equipment in mineral transportation and separation systems, and it has complex two-phase flow characteristics and wear mechanisms. By employing numerical and experimental methods, the solid–liquid two-phase flow characteristics and wear patterns were investigated in this study. A two-way coupling discrete phase model (DPM) method was used to predict the flow pattern and the wear location and shows good agreement with the experimental observations. The pump performance characteristics of numerical results under pure water conditions were consistent with the experimental results. The effects of particle parameters and operating conditions on the internal flow field and wear were compared and discussed. The results show that the wear degree increased with the increase in volume flow rate and solid volume fraction. With the increase in particle size, the wear range at the impeller inlet became significantly smaller, but the wear degree became obviously larger. This study provides a basis for reducing the wear and improving the hydraulic performance of slurry pumps.

INVESTIGATION OF STRATIFIED WAVY TWO-PHASE FLOW CHARACTERISTICS

Equipment ◽  
2006 ◽  
Author(s):  
Marijus Seporaitis ◽  
S. Gasiunas ◽  
Raimondas Pabarcius
Keyword(s):  
Two Phase Flow ◽  
Flow Characteristics ◽  
Phase Flow ◽  
Two Phase

Investigation of air-water two-phase flow characteristics in a 25.4 mm diameter circular pipe

2021 ◽  
pp. 103813
Author(s):  
Dewei Wang ◽  
Shanbin Shi ◽  
Yucheng Fu ◽  
Kyle Song ◽  
Xiaodong Sun ◽  
...  
Keyword(s):  
Two Phase Flow ◽  
Flow Characteristics ◽  
Circular Pipe ◽  
Phase Flow ◽  
Two Phase

scholarly journals Experimental data for the slug two-phase flow characteristics in horizontal pipeline

Data in Brief ◽  
2018 ◽  
Vol 16 ◽  
pp. 527-530 ◽  
Author(s):  
Abdalellah O. Mohmmed ◽  
Mohammad S. Nasif ◽  
Hussain H. Al-Kayiem
Keyword(s):  
Experimental Data ◽  
Two Phase Flow ◽  
Flow Characteristics ◽  
Phase Flow ◽  
Two Phase

Experimental Study of Two-Phase Flow Induced by Cavitation Through a Safety Relief Valve

2013 ◽  
Author(s):  
Jorge Pinho ◽  
Patrick Rambaud ◽  
Saïd Chabane
Keyword(s):  
Local Minimum ◽  
Two Phase Flow ◽  
Flow Characteristics ◽  
Control Valve ◽  
Recovery Factor ◽  
Phase Flow ◽  
Relief Valve ◽  
Two Phase ◽  
Blow Down ◽  
Choked Flow

The goal of this study is to understand the behavior of a safety relief valve in presence of a two-phase flow induced by cavitation, in which the mass flux tends to be reduced. Two distinct safety relief valves are tested: an API 2J3 type and a transparent model based on an API 1 1/2G3 type. Instead of using a spring, the design of both valves allows the adjustment of the disk at any desired lift. Tests are conducted with water at ambient temperature. Results show a similar influence of cavitation on the flow characteristics of both valves. The liquid pressure recovery factor FL, which is normally used to identify a choked flow condition in a control valve, is experimentally determined in a safety relief valve. The existence of a local minimum located at a height position L/D = 0.14 indicates in this position, a change on the flow characteristics of both valves. It is verified that the existence of a local minimum in the liquid recovery factor is related to the minimum cross section of the flow, which does not remain constant for every lift positions. Furthermore, it is remarked that in the case of the 2J3 safety valve, the blow down ring adjustment has significant influence on the location of the minimum cross sections of the flow.

Eulerian Two-Phase Flow Modeling of Steam Direct Contact Condensation for the Fukushima Accident Investigation

2014 ◽  
Author(s):  
Marco Pellegrini ◽  
Giulia Agostinelli ◽  
Hidetoshi Okada ◽  
Masanori Naitoh
Keyword(s):  
Two Phase Flow ◽  
Volume Fraction ◽  
Fluid Model ◽  
Fluid Dynamic ◽  
Interfacial Region ◽  
Phase Flow ◽  
Two Phase ◽  
Fukushima Accident ◽  
Average Cell Size ◽  
Average Cell

Steam condensation is characterized by a relatively large interfacial region between gas and liquid which, in computational fluid dynamic (CFD) analyses, allows the creation of a discretized domain whose average cell size is larger than the interface itself. For this reason generally one fluid model with interface tracking (e.g. volume of fluid method, VOF) is employed for its solution in CFD, since the solution of the interface requires a reasonable amount of cells, reducing the modeling efforts. However, for some particular condensation applications, requiring the computation of long transients or the steam ejected through a large number of holes, one-fluid model becomes computationally too expensive for providing engineering information, and a two-fluid model (i.e. Eulerian two-phase flow) is preferable. Eulerian two-phase flow requires the introduction of closure terms representing the interactions between the two fluids in particular, in the condensation case, drag and heat transfer. Both terms involve the description of the interaction area whose definition is different from the typical one adopted in the boiling analyses. In the present work a simple but effective formulation for the interaction area is given based on the volume fraction gradient and then applied to a validation test case of steam bubbling in various subcooling conditions. It has been shown that this method gives realistic values of bubble detachment time, bubble penetration for the cases of interest in the nuclear application and in the particular application to the Fukushima Daiichi accident.

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