Study of the impact of aeration on the lubricant behavior in a tapered roller bearing: innovative numerical modelling and validation via particle image velocimetry

2021 ◽  
pp. 107301
Author(s):  
Lorenzo Maccioni ◽  
Valery G. Chernoray ◽  
Marco N. Mastrone ◽  
Christof Bohnert ◽  
Franco Concli
2017 ◽  
Author(s):  
Silvia Matt ◽  
Gero Nootz ◽  
Samuel Hellman ◽  
Weilin Hou

2014 ◽  
Vol 136 (11) ◽  
Author(s):  
Xiang Luo ◽  
Dongdong Liu ◽  
Hongwei Wu ◽  
Zhi Tao

In this article a combined experimental and numerical investigation of the unsteady mixing flow of the ingestion gas and rim sealing air inside a rotating disk cavity was carried out. A new test rig was set up, and the experiments were conducted on a 1.5-stage turbine rotor disk and included pressure measurements. The flow structure of the mixing region of the ingestion gas and sealing air in cavity was measured using the particle image velocimetry (PIV) technique. To complement the experimental investigation and to aid in understanding the flow mechanism within the cavity, a three-dimensional (3D) unsteady computational fluid dynamic (CFD) analysis was undertaken. Both simulated and experimental results indicated that near the rotating disk, (i) a large amount of the ingestion gas will turn around and flow out the cavity due to the impact of the centrifugal force and the Coriolis force, (ii) a small amount of ingestion gas will mix transiently with the sealing air inside the cavity, whereas near the static disk, (iii) the ingestion gas will flow into the cavity along the static wall and mix with the sealing air.


2018 ◽  
Vol 70 (1) ◽  
pp. 191-200 ◽  
Author(s):  
Sier Deng ◽  
Jinfang Gu ◽  
Yongcun Cui ◽  
Wenhu Zhang

Purpose This study aims to analyze the roller dynamic characteristics and cage whirling of tapered roller bearing considering roller tilt and skew which provide a theoretical basis for the design and application of tapered roller bearing. Design/methodology/approach Based on rolling bearing dynamic analysis, the dynamic differential equations of tapered roller bearing are established. Fine integral method and predict correct Adams–Bashforth–Moulton multi-step method are used to solve the dynamic differential equations of tapered roller bearings. Findings Friction at the flange contact between roller and large flange is the chief factor of roller skew. In comparison to cone speed, axial loads have more visible effect on roller skew, and proper speed or axial load is beneficial to sustain cage motion and decrease cage instability. Under the combined effort of axial load and radial load, the distribution of roller skew is correlated to the roller-flange contact load. In addition, roller skew angle in loaded zone is larger than that in unloaded zone; hence, it is helpful for cage stability if an extent radial load is applied. The pocket clearance of cage has very small influence on roller skew; therefore, a reasonable pocket clearance is suggested to assure minimum instability of cage. Friction coefficient of flange contact has a large effect on roller skew, and cage whirl is found to demonstrate a circular orbit with increasing friction coefficient. Originality/value The dynamic differential equations of tapered roller bearing considering roller large end/inner ring back face rib contact under various lubrication states were established. The impact of flange friction working conditions and cage pocket clearance on cage instability and roller skew were focused on. It is the first time that the ratio of the standard deviation of the cage-center translational speed to its mean value is used to access the instability of cage in tapered roller bearing.


Author(s):  
Liu Xueqing ◽  
Lu Luyi

The impinging Stream is a novel technique in enhancing heat and mass transfer. In the conventional impinging stream reactor (ISR), as the particles in that reactor are affected by the fluid resistance, the energy of the particles is rapidly decreased after the infiltration of the reverse flow, which leads to the effective mixing of the particles. In this paper, we design an improved impinging stream reactor (IISR) that has different fluid inlet velocity but same mean fluid inlet velocity in a period, which still belongs to definition of impinging stream. In the present study, the flow characteristics in the IISR are investigated using particle image velocimetry (PIV) and computational fluid dynamics. The effects of the fluid inlet velocity in the axisymmetric opposed jets are discussed for equal mean volumetric flow rates of the two jets. The impingement plane and the flow filed of the IISR are measured from captured images using the PIV technique. The two fluid inlet velocity with different sinusoidal variations are applied in the improved impinging stream. Besides, the experimental results show that the impingement plane is moving instantaneously with the two inlet velocity changing dynamically, which expands efficient active areas compared with the conventional impinging stream. Besides, computational fluid dynamics are used in combination with the discrete phase model (CFD-DPM) to predict the flow characteristics within the improved Impinging Stream. The simulation results show that impinging stream flow field can be divided into the inlet, the impact zone, the exit zone and the vortex area. At the same time, the impact zone and the impingement plane is also found to be moving The CFD-DPM results give predictions that are in better agreement with the flow filed pictured by the PIV technique. Because of the complexity of the liquid immersion impinging stream, it is difficult to study the trajectory of the particles in the flow field, so we use the numerical simulation to study the motion of the particles in the immersion IISR. Analysis shows the effective mixing region of the particles can be greatly increased, particles’ motion trajectory can be longer and the heat and mass transfer between the particles and the interphase can be further enhanced. Compared with the conventional ISR, the IISR has obvious advantages. The results point out this improved impinging Stream has a good application prospect in future engineering works.


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