This thesis describes the development of an ElastoHydroDynamic (EHD) bearing calculation. The effect of body forces is shown to be important for highly loaded bearings in reciprocating internal combustion engines. Extension of the program to rotating machinery includes an examination of instability in the shaft bearings of a turbocharger. The development of a parameter to predict cavitation damage in a bearing is promising. Several calculation results using the program are shown. These are engine main bearing and connecting rod big-end bearings and full floating bearings for a turbocharger. The calculations on the big-end bearing if a racing engine show why the designers were having difficulty understanding the correct location for the oil feed hole position. Effects of elastic deformation, thermal deformation and manufacturing/assembly deformation all have a significant effect on the extent of the oil film. A novel calculation for a cavitation damage parameter is demonstrated successfully for a heavily loaded diesel engine bearing. The importance of body forces on the oil film due to high accelerations on certain bearings is shown to be theoretically important but not yet demonstrated. The program was written with the intention to be incorporated into the sponsoring company’s range of engine design software. A part of that development process included carrying out calculations to demonstrate to customers and present papers at conferences. The results of some of these calculations have been included in this thesis. Results of a study on the effect of crankshaft geometry on racing engine viscous friction losses were reported in a paper presented at the IDETC conference in Long Beach, 2005. This study used the first version of the software which only included Rigid Hydro Dynamics (RHD) at the time but was usable. Results of a study on stability of shaft motion in high speed turbocharger bearings were reported in a paper at the 8th International Turbocharger conference in London, 2006. At this time the program was still only capable of RHD calculations but could now solve for multiple oil films simultaneously and sweep through the speed range. The studies on the effects of body forces and the development of a cavitation parameter will be presented in papers in the near future.

In industrial situations time is expensive and simulation accuracy is not always investigated because it requires grid refinement studies or other time consuming methods. With this in mind the goal of this research is to develop a method to assess the errors and uncertainties on computational fluid dynamics (CFD) simulations that can be adopted by industry to meet their requirements and time constraints. In a CFD calculation there are a number of sources of errors and uncertainties. An uncertainty is a potential deficiency that is due to a lack of knowledge of an activity of the modelling process, for example turbulence modelling. An error is defined as a recognisable deficiency that is not due to a lack of knowledge, for example numerical discretisation error. The process of determining the level of errors and uncertainties is termed verification and validation. The work aims to define an error estimation method for verification of numerical errors that can be produced during one simulation on a single grid. The second moment solution error estimate for scalar and vector quantities was proposed to meet these requirements. Where the governing equations of CFD, termed the first moments, represent the transport of primary variables such as the velocity, the second moments represents the transport of the primary variables squared such as the total kinetic energy. The second moments are formed by a rearrangement of the first moments. Based on a mathematical justification, an error estimate for vector or scalar quantities was defined from combinations of the solutions to the first and second moments. The error estimate was highly successful when applied to six test cases using laminar flow and scalar transport. These test cases used either central differencing with Gaussian elimination, or the finite volume method with the CFD solver Code_Saturne to conduct the simulations, demonstrating the applicability of the error estimate across solution methods. Comparisons were made to the numerical simulation errors, which were found using either the analytical or refined solutions. The comparisons were aided by the normalised cross correlation coefficient, which compared the similarity of the shape prediction, and the averaged summation coefficients, which compared the scale prediction. When using the first order upwind scheme the method consistently produced good predictions of the locations of error. When using the second order centred or second order linear upwind schemes there was similar success, but limited by influences from solution unboundedness, non-resolution of the boundary layer, the near-wall gradient approximation, and numerical pressure error. At high Reynolds numbers these caused the prediction of the location of error to degrade. This effect was made worse when using the second order schemes in conjunction with the constant value boundary condition. This was the case for the scalar or velocity simulations, and is caused by the unavoidable drop to first order accuracy during the near-wall gradient approximation that is required for the second moment source term approximation. The prediction of the scale demonstrated a dependence on the cell Peclet number. Below cell Peclet number 4 the increase of the estimate scale was linearly related to the increase of the error scale. The estimate scale consistently over-predicts by up to a factor of 3. This allows confidence that the true error level is below that which is predicted by the error estimate. At cell Peclet numbers greater than 4 the relationship between the scales remained linear, however, the estimate begins to under-predict the estimate. The exact relation becomes case dependent, and the highest under-prediction was by a factor of 10. In such circumstances a computationally inexpensive calibration can be done.

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The study of rotor blade aerodynamic performances of wind tur- bine has been presented in this thesis. This study was focused on aero- dynamic effects changed by blade surface distribution as well as grid solution along the airfoil. The details of numerical calculation from Fluent were described to help predict accurate blade performance for comparison and discussion with available data. The direct surface curvature distribution blade design method for two-dimensional airfoil sections for wind turbine rotors have been dis- cussed with the attentions to Euler equation, velocity diagram and the factors which affect wind turbine performance and applied to design a blade geometry close to an existing wind turbine blade, Eppler387, in order to argue that the blade surface drawn by direct surface curvature distribution blade design method contributes aerodynamic efficiency. The FLUENT calculation of NACA63-215V showed that the aero- dynamic characteristics agreed well with the available experimental data at lower angles of attack although it was discontinuities in the surface curvature distributions between 0.7 and 0.8 in x/c. The dis- continuities were so small that the blade performance could not be affected. The design of Eppler 387 blade performed to reduce drag force. The discontinuities of surface distributionmatched the curve of the pressure coefficients. It was found in the curvature distribution that the leading edge pressure side had difficulties to connect to Bezier curve and also the trailing edge circle was never be tangent to the lines of trailing edge pressure and suction sides due to programming difficulties.

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