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A theoretical model is developed which allows an expression for film thickness to be developed. The model approximates the film shape in the main load bearing region by a tilted pad and outside the main load bearing region by the equivalent dry contact solution. Two theories are developed, the modified and limited theories, the limited theory being valid for very small values for the slope of the tilted pad. Expressions for the frictional traction and starvation parameters are also developed for the two theories. The model used is applicable for intermediate and heavy loads. Values of film thickness obtained from the modified and limited theories are below those predicted by more rigorous theories (e.g., Herrebrugh), because the displacements due to the lubricant pressure in the inlet region are ignored for the former. The inlet ::one theory, which takes account of these displacements, produces a value for film thickness which is comparable to that obtained by Herrebrugh. The exit zone theory, which takes account of the additional displacements in the exit region, predicts a value for the ratio of minimum to central film thickness which is comparable to that obtained by Herrebrugh. Improved values for the frictional and starvation parameters are obtained using the inlet zone theory. Pressure curve and film thickness values are obtained from experimental rigs, for comparison with theory. The pressure rig utilises a pressure transducer for pressure measurement, whereas the film thickness rig utilises the principle of optical interferometry for film thickness measurement. It is concluded that the initial tilted pad model is a valid approximation to the shape of the loaded region, providing a conservative estimate of film thickness for the bearing designer. The use of an improved shape in the inlet and exit regions improves the agreement between experiment and theory.

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The dynamio characteristics of journal bearings have been predicted by solving Reynolds equation with a common cavitation model. A perturbation analysis has been used to express the equations governing the fluid film pressure and cavitation region state in terms of a dynamic journal displacement vector. The use of these equations has been demonstrated on the long and short bearing approximations. The stability performance has been predicted for both rigid and flexible bearing systems. A perspex test bearing has been used to observe cavitation under steady and dynamio loads, and a high speed test apparatus was developed for the measurement of lubricating film performance at whirl onset conditions. Although the test results were consistent and repeatable, the stability performance of the bearings tested was substantially less than the predictions of the simple bearing theory and other workers results. It is thought that the poor performance was due to oil starvation.

In this computer-aided study, existing methods of determining the fluid flow in axial flow turbomachines are examined, and the Consistent Loss Model of Bosman and Marsh is here applied to both duct flow and intrablade applications of the Streamline Curvature technique. The resulting equations are presented in a form similar to that of the conventional equations, thus providing for easy modification of existing Streamline Curvature method computer programs. Interpretation of the equations shows that the mean flow through a blade row passage cannot follow a parabolic path between the blade inlet and outlet flow angles, as is commonly assumed, but must maintain as continuous the streamwise derivative of angular momentum. Procedures are described to design three-dimensional blade shapes from basic aero foil data, and to derive realistic intrablade mean stream surfaces, including allowances for flow deviation and secondary flow. Numerical techniques are presented which have been developed for closely-spaced intrablade calculation grids, to obtain faster convergence than by conventional schemes in Streamline Curvature calculations. The computer program is intended for analysing multi-stage axial flow compressors; tests are presented of simple analytical cases and experimental data for isolated rows of blades, of a' swan-necked' duct, and of a three-row experimental compressor. Three-dimensional flow calculation methods are reviewed with reference to the limitations inherent in applying them to axial flow turbomachines. Suggestions are made for future work.

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No description available.

No description available.

No description available.