This thesis concentrates on accuracy improvements for an existing software package that solves the three dimensional Reynolds Averaged Navier-Stokes equations in rotating coordinates. It is a cell centred explicit time marching code. Two topics are considered: improvement to the discretization scheme, and reduction of the artificial dissipation. The first topic is the analysis of the straight averaging process which demonstrates that the process can result in inconsistency with a skewed grid. An alternative consistent scheme is proposed which is based upon quadratic interpolation. Improved accuracy can also be obtained by modifying the grid or adopting a cell vertex scheme. The stability of the iterative process is also shown to depend on the time step. The reduction of artificial dissipation (second topic) first considers the role of the so called aspectratio and velocity functions. These are found to be limited in influence and a new function is proposed based upon the local flow gradient. Both two and three dimensional turbomachinery cases are tested and improvements demonstrated. In the second part of the analysis, the eigenvalues of the stability matrix are used to reduce the dissipation in overdamped regions. Again this method is applied to various test cases and improvements demonstrated. The management part of this Total Technology PhD Program discusses topics concerned with collaboration and technology development in the aero engine industry with particular emphasis on the role of an 'emerging' partner.

En même temps: Thèse sc. humaines Neuchâtel, 2007 (version remaniée). / Bibliogr. Index.

The present study aims to explore the dynamical behavior in the uniform flow by numerical method. The theoretical model is based on transient of continuity equation and momentum equation in CFD software: Fluent. With User Define Function¡]UDF¡^, we can simulate the Vortex-induced vibration¡]VIV¡^under the uniform flow by numerical method and plot the contour of amplitude and flow field under different Reynolds number. We will identify the accurate and capable of central difference method in UDF by comparing with the previous study. Also, we focus on whether the amplitude and flow situation will effect by uniform flow in different degrees or not. Furthermore, this study shows how the time step size and mesh effect the conclusion so that we could have the best choice on model.

This thesis deals with the problem of designing vortex flow meter for a nominal range of 40 l.min-1. It describes the problems of vortex bodies and choice of methods for detection of vortices. The thesis includes solution of various problems in the design, which were published in scientific articles or patents. The following describes the design solution vortex flow meter for the specified range, which uses ultrasonic sensors to vortices detection. The proposed flow meter is calibrated with reference flow meter and compared with commercially produced vortex flow by the TST electronics and Burkert companies, which are designed for the specified ranges.

Mobile Miner 40V is a machine used for rock excavation and developed by Epiroc. This machine is equipped with a large cutter wheel to perform the excavation. After a test run, some surfaces associated with bearings within the cutter wheel were found to be damaged due to scuffing - severe sliding wear. There is a static load applied to the surfaces due to gravity. However, the reason for this damaged issue was believed that there is a large dynamic load applied to the surfaces during the excavation. This dynamic load was not found in a previous FE model used to verify safety issues. Therefore, a new FE model that is more in line with reality, and a failure analysis were required. Additionally, a feasibility study for a cutter wheel with a larger dimension was also needed since a larger cutter wheel is desirable. Firstly, wear mechanisms were reviewed, and some theories were chosen to analyze the damaged issue. Since it was unknown whether the surfaces were well-lubricated or not, both cases were investigated. The Archard wear equation was used to analyze the poor-lubricated situation, while the lubrication number and the Reynolds equation were used to analyze the well-lubricated case. Secondly, contact mechanisms between the surfaces were also investigated. The investigation of the contact mechanisms involved several theories, such as the Hertzian contact theory and the impact load factor. Besides these theoretical analyses, a numerical analysis was performed. Lastly, a new FE model was established in Ansys. Both the cutter wheel which was subjected to scuffing(existing cutter wheel), and the cutter wheel with a larger dimension(larger cutter wheel) were analyzed by the use of the new FE model. The maximum and minimum wear rates obtained by the Archard wear equation are approximately 1.9・10-2mm3/m and 4.8・10-3mm3/m, which are considered as a completely unacceptable level in engineering applications. The maximum and minimum critical loads obtained by the Reynold equation are approximately 1.8kN and 24.8kN, which both are larger than the static load applied to the surfaces. The maximum and minimum critical mean contact pressures obtained by the lubrication number are approximately 65MPa and 240MPa, which both are larger than the mean contact pressure generated by the static load. No evidence shows that there is a large dynamic load applied to the surfaces during the excavation. The largest possible contact pressure on the bearings in the existing cutter wheel is very close to the limit of severely damaged. The largest possible contact pressure on the bearings in the larger cutter wheel is believed to exceed the limit of severely damaged. The previous assumption that the surfaces were damaged due to a large dynamic load was wrong. The obtained results support that the surfaces were only subjected to a static load and were damaged due to inadequate lubrication. The existing cutter wheel is operated safely with the current load cases. However, the forward thrust force is suggested to decrease when the cutting angle is large. There is a high risk if the larger cutter wheel is operated with the current load cases.