“…Basic geometry of the four-lobe four pocket hybrid journal bearing is illustrated in Figure 1. For a finite journal bearing system operating in turbulent regime, the usual Reynolds equation is modified by using turbulent lubrication theory of Constantinecscu and is expressed as follows 35 where, G¯α and G¯β are turbulent coefficients and functions of local Reynolds number Re* in turbulent regime 35,42 Figure 1.Geometrically imperfect four-lobe four pocket hybrid journal bearing.…”
Section: Discussionmentioning
confidence: 99%
“…The frictional torque exerted on journal surface is defined in nondimensional form as 35,42 where, τ¯c is known as normalized turbulent coquette shearing stress and defined as τ¯c =1, for laminar flow…”
Section: Discussionmentioning
confidence: 99%
“…41 studied the influence of wear on performance characteristics of hydrodynamic bearings system operating under laminar and turbulent regime. Kumar and Rao 42 determined the stability characteristics of hybrid porous journal bearing operating in turbulent regime. They applied the Constantinecscu's turbulent theory of fluid film to follow the behaviour of turbulent fluid film.…”
Section: Introductionmentioning
confidence: 99%
“…Recently, the nature of turbulence in fluid film journal bearing has been extensively investigated by many researchers. [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] The pioneering interest in turbulent lubrication was shown by Taylor 30 who obtained the critical Reynolds number for unloaded journal bearing to differentiate between laminar and turbulent flow regime. Wilcock 31 experimentally observed the turbulent flow behaviour in fluid film journal bearing and noticed a significant enhancement in load carrying capacity, drag loss and fluid film pressure.…”
The present study deals with the influence of geometric irregularities of journal (barrel type, bellmouth type and undulation type) on the performance of capillary compensated four-lobe multirecess hybrid journal bearing system operating in the turbulent regime. The Reynolds equation governing turbulent flow of lubricant has been modified by using the turbulent lubrication theory of Constantinecscu and has been solved by using the finite element method. It has been observed that turbulence deteriorates the bearing stability threshold speed margin. Further, the computed results demonstrate that the four-lobe bearing (δ=0.8) provides higher value of fluid film stiffness and stability threshold speed margin than the circular bearing operating in turbulent regime.
“…Basic geometry of the four-lobe four pocket hybrid journal bearing is illustrated in Figure 1. For a finite journal bearing system operating in turbulent regime, the usual Reynolds equation is modified by using turbulent lubrication theory of Constantinecscu and is expressed as follows 35 where, G¯α and G¯β are turbulent coefficients and functions of local Reynolds number Re* in turbulent regime 35,42 Figure 1.Geometrically imperfect four-lobe four pocket hybrid journal bearing.…”
Section: Discussionmentioning
confidence: 99%
“…The frictional torque exerted on journal surface is defined in nondimensional form as 35,42 where, τ¯c is known as normalized turbulent coquette shearing stress and defined as τ¯c =1, for laminar flow…”
Section: Discussionmentioning
confidence: 99%
“…41 studied the influence of wear on performance characteristics of hydrodynamic bearings system operating under laminar and turbulent regime. Kumar and Rao 42 determined the stability characteristics of hybrid porous journal bearing operating in turbulent regime. They applied the Constantinecscu's turbulent theory of fluid film to follow the behaviour of turbulent fluid film.…”
Section: Introductionmentioning
confidence: 99%
“…Recently, the nature of turbulence in fluid film journal bearing has been extensively investigated by many researchers. [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] The pioneering interest in turbulent lubrication was shown by Taylor 30 who obtained the critical Reynolds number for unloaded journal bearing to differentiate between laminar and turbulent flow regime. Wilcock 31 experimentally observed the turbulent flow behaviour in fluid film journal bearing and noticed a significant enhancement in load carrying capacity, drag loss and fluid film pressure.…”
The present study deals with the influence of geometric irregularities of journal (barrel type, bellmouth type and undulation type) on the performance of capillary compensated four-lobe multirecess hybrid journal bearing system operating in the turbulent regime. The Reynolds equation governing turbulent flow of lubricant has been modified by using the turbulent lubrication theory of Constantinecscu and has been solved by using the finite element method. It has been observed that turbulence deteriorates the bearing stability threshold speed margin. Further, the computed results demonstrate that the four-lobe bearing (δ=0.8) provides higher value of fluid film stiffness and stability threshold speed margin than the circular bearing operating in turbulent regime.
“…[1] to [3] by substituting Eq. [5] and gathering the e 0 ; e 1 e it and e 0 f 1 e it terms, a set of linear differential equations in p , and p 0 are solved simultaneously with appropriate boundary conditions for steady-state pressures in the film as well as porous regions. The partial derivatives are written in finite difference form using a central difference method and then solved by using the Gauss-Seidel iteration method with a successive overrelaxation (SOR) scheme.…”
A theoretical investigation has been carried out for stability characteristics of a finite hydrostatic double-layer porous oil journal bearing considering the effect of Beavers-Joseph velocity slip at the porous film interface. A linearized perturbation method has been used to obtain the threshold of stability in terms of critical mass parameter. The effect of slip parameters, eccentricity ratios, bearing feeding parameter, and slenderness ratio on the stability is investigated. Furthermore, nonlinear transient analysis is carried out to determine the system stability by tracing the journal center locus. Several trajectories of the journal center locus have been obtained for different operating conditions and are depicted with the help of graphics.
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