An Experimental Investigation of Pressure Distributions in a Journal Bearing Operating in the Transition Regime

Abstract

Experimental results are presented, relating to friction factors and circumferential pressure distributions, for a plain cylindrical ,journal bearing with a central circumferential inlet groove. The length-diameter ratio of each journal bearing land was 0.25 and the clearance ratio was 0.0031. The friction factor results showed the existence of a distinct 'transition regime', characterized by a pronounced 'hump' in the friction factor-Reynolds number relationship. Pressure measurements recorded when operating in this transition regime revealed the inadequacy of many existing 'turbulent' theories for superlaminar lubrication. By using a short-bearing theory a good correlation of the pressure distribution results was obtained, in terms of a non-dimensional viscosity parameter, k,, which is dependent on both the eccentricity ratio and Reynolds number. The magnitude of k, in this regime was considerably higher than the corresponding value for laminarflow, and was similar to the magnitude predicted.from a simple theory based on relating k , to the variation of measured friction factor with Reynolds number.

Fluid‐Structure Interaction Analysis on Turbulent Annular Seals of Centrifugal Pumps during Transient Process

“…Proper models that simulate all three states flow should be selected to study the influence of the annular seal flow on the transient response of rotor systems through the start-up process. Based on the three turbulent theories and transition regime model presented by con and Roberts et al 3,15,16,19 numerical results were obtained and then compared with the experimental results. Figure 2 is the schematic of the annular seal flow channel cross-section.…”