Abstract:Two-lobe pressure dam bearings are commonly used in high speed rotating machineries. Their use is considered more stable than plain cylindrical bearings. Such bearings have a dam in the upper half whereas the lower half is provided with a relief track. Performance of two-lobe pressure dam bearings under micropolar fluid is evaluated. Finite element method is used to solve the modified Reynolds equation. Fluid film pressures are obtained by solving modified Reynolds equation. Thus pressure obtained is used to f… Show more
“…Behaviour of critical mass at different L/D values presented in Figure 15 is similar as of Sharma and Krishna. 25 It is evident from the earlier research that strong micropolarity effects are observed at smaller values of l m . Figure 15.Variations of critical mass with characteristics length.…”
Section: Resultsmentioning
confidence: 86%
“…In continuation of the above work, few researchers 24,25 worked on two-lobe pressure dam bearings with micropolar lubrication instead of Newtonian fluid and found better performance than Newtonian. But still, there is a lack of information available for a detailed comparative study of two-lobe pressure dam bearings with micropolar lubrication.…”
Section: Introductionmentioning
confidence: 93%
“…The dynamic form of the non-dimensional generalized equation representing laminar flow in the clearance space of any lobe is given by Sharma and Krishna, 25 as given below …”
A circular bearing experiences the instability problem due to oil whirl, causing violent vibrations at high speed. Two-lobe pressure dam bearing is a solution to the instability arising in high-speed rotating machineries. The paper presents the various static and dynamic characteristics of two-lobe pressure dam bearings, while operating with micropolar fluid. The modified Reynolds equation used to model the lubrication is solved using the finite element method. Performance characteristics such as load, attitude angle, critical mass, threshold speed and whirl frequency are computed, presented graphically and analysed. A detailed comparison of the performance characteristics is done for various micropolar and dam parameters. It is concluded that bearing performance is significantly influenced by dam parameters (dam angles) and micropolar parameters (coupling number and characteristics length).
“…Behaviour of critical mass at different L/D values presented in Figure 15 is similar as of Sharma and Krishna. 25 It is evident from the earlier research that strong micropolarity effects are observed at smaller values of l m . Figure 15.Variations of critical mass with characteristics length.…”
Section: Resultsmentioning
confidence: 86%
“…In continuation of the above work, few researchers 24,25 worked on two-lobe pressure dam bearings with micropolar lubrication instead of Newtonian fluid and found better performance than Newtonian. But still, there is a lack of information available for a detailed comparative study of two-lobe pressure dam bearings with micropolar lubrication.…”
Section: Introductionmentioning
confidence: 93%
“…The dynamic form of the non-dimensional generalized equation representing laminar flow in the clearance space of any lobe is given by Sharma and Krishna, 25 as given below …”
A circular bearing experiences the instability problem due to oil whirl, causing violent vibrations at high speed. Two-lobe pressure dam bearing is a solution to the instability arising in high-speed rotating machineries. The paper presents the various static and dynamic characteristics of two-lobe pressure dam bearings, while operating with micropolar fluid. The modified Reynolds equation used to model the lubrication is solved using the finite element method. Performance characteristics such as load, attitude angle, critical mass, threshold speed and whirl frequency are computed, presented graphically and analysed. A detailed comparison of the performance characteristics is done for various micropolar and dam parameters. It is concluded that bearing performance is significantly influenced by dam parameters (dam angles) and micropolar parameters (coupling number and characteristics length).
“…They observed that aspect ratio affect the stability of journal bearing at some extent. Sufficient amount of work have been done on performance characteristics taking into account of the effect of aspect ratio [5][6][7][8][9][10][11]. Das et al [5] presented the performance of hydrodynamic journal bearing operated with micro-polar fluids at various aspect ratio and eccentricity ratio.…”
Section: Introductionmentioning
confidence: 99%
“…They concluded that the stability of this type of journal bearing highly depends upon the L/D ratio and the stability decreases with increasing L/D ratios. Sharma and Krishna [8] studied the performance parameters 2-lobe pressure dam bearing using micro-polar fluids at different L/D ratios (1.6, 2.0 and 2.4). They concluded that the stability of bearing is increases with decreasing aspect ratio.…”
This article presents the static performance characteristics of a plain journal bearing with non-Newtonian lubricant (power law) at different aspect ratio. Finite difference approach is employed to solve the modified Reynold equation. Hydrodynamic regime is assumed to be isothermal. The fluid film pressure is established using modified Reynold equation and Reynold boundary condition through iteratively. Thus the obtain pressure is used to find-out the performance characteristics for instance load carrying capacity, attitude angle, friction force and side leakage. Three aspect ratios are assumed 0.5, 1 and 1.5 for the present study. The effect of different aspect ratios on performance characteristics at different power law index (0.9, 1 and 1.1) has been presented.
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