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Effects of Hindrance Factors on a Squeeze Film of a Porous Bearing Lubricated With a Dehaven Fluid

Walicka A., Walicki E., Jurczak P., Falicki J.

Machine Dynamics Research

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2018

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Vol. 42, No. 1

15--33

EN

In the paper the influence of the hindrance factors on the pressure distribution and loadcarrying capacity of a curvilinear thrust porous bearing is discussed. The equations of motion of a pseudo-plastic fluid of DeHaven are used to derive the Reynolds equation. The general considerations on the flow in a bearing clearance were presented. The analytical considerations on the flow in a thin porous layer composed of capillaries were also presented. Two models of the porous region were used, e.g.: capillary tube with constant cross-section and capillary tube with variable cross-section with rectilinear generatrices. Next, using the Morgan-Cameron approximation the modified Reynolds equation was obtained. As a result the formulae expressing pressure distribution and load-carrying capacity were obtained. Thrust radial bearing with a squeeze film of DeHaven fluid was considered as an example.

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Flows of DeHaven fluid in symmetrically curved capillary fissures and tubes

Walicka A., Falicki J., Jurczak P.

International Journal of Applied Mechanics and Engineering

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2018

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Vol. 23, no. 2

521--550

EN

In this paper, an analytical method for deriving the relationships between the pressure drop and the volumetric flow rate in laminar flow regimes of DeHaven type fluids through symmetrically corrugated capillary fissures and tubes is presented. This method, which is general with regard to fluid and capillary shape, can also be used as a foundation for different fluids, fissures and tubes. It can also be a good base for numerical integration when analytical expressions are hard to obtain due to mathematical complexities. Five converging-diverging or diverging-converging geometrics, viz. variable cross-section, parabolic, hyperbolic, hyperbolic cosine and cosine curve, are used as examples to illustrate the application of this method. Each example is concluded with a presentation of the formulae for the velocity flow on the outer surface of a thin porous layer. Upon introduction of hindrance factors, these formulae may be presented in the most general forms.

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Curvilinear squeeze film bearing lubricated with a DeHaven fluid or with similar fluids

Walicka A., Jurczak P., Falicki J.

International Journal of Applied Mechanics and Engineering

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2017

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Vol. 22, no. 3

697--715

EN

In the paper, the model of a DeHaven fluid and some other models of non-Newtonian fluids, in which the shear strain rates are known functions of the powers of shear stresses, are considered. It was demonstrated that these models for small values of material constants can be presented in a form similar to the form of a DeHaven fluid. This common form, called a unified model of the DeHaven fluid, was used to consider a curvilinear squeeze film bearing. The equations of motion of the unified model, given in a specific coordinate system are used to derive the Reynolds equation. The solution to the Reynolds equation is obtained by a method of successive approximations. As a result one obtains formulae expressing the pressure distribution and load-carrying capacity. The numerical examples of flows of the unified DeHaven fluid in gaps of two simple squeeze film bearings are presented.