This thesis presents a multi-grid scheme applied to the solution of transport equations in turbulent flow associated with heat transfer. The multi-grid scheme is then applied to flow which occurs in the film cooling of turbine blades. The governing equations are discretized on a staggered grid with the hybrid differencing scheme. The momentum and continuity equations are solved by a nonlinear full multi-grid scheme with the SIMPLE algorithm as a relaxation smoother. The turbulence k — Є equations and the thermal energy equation are solved on each grid without multi-grid correction. Observation shows that the multi-grid scheme has a faster convergence rate in solving the Navier-Stokes equations and that the rate is not sensitive to the number of mesh points or the Reynolds number. A significant acceleration of convergence is also produced for the k — Є and the thermal energy equations, even though the multi-grid correction is not applied to these equations. The multi-grid method provides a stable and efficient means for local mesh refinement with only little additional computational and.memory costs. Driven cavity flows at high Reynolds numbers are computed on a number of fine meshes for both the multi-grid scheme and the local mesh-refinement scheme. Two-dimensional film cooling flow is studied using multi-grid processing and significant improvements in the results are obtained. The non-uniformity of the flow at the slot exit and its influence on the film cooling are investigated with the fine grid resolution. A near-wall turbulence model is used. Film cooling results are presented for slot injection with different mass flow ratios. / Science, Faculty of / Mathematics, Department of / Graduate

The topic of this diploma thesis is a condensing steam turbine with one regulated steam extraction. The first part contents design and balance of heat scheme. The heat scheme is the basis for the main part of this work, which is the thermodynamic design of the turbine with reaction blades. At the end, the characteristics of the turbine are created. Drawing of the turbine section is attached to this thesis.

The main aim of this diploma thesis is design and calculation of steam condensing turbine with given parameters. In the first part is made calculation of heat balance scheme, which contains high and low pressure regeneration and turbine with total of 5 unregulated steam extraction. It is followed by calculation of regulating stage with impulse blading and calculation of stage part of turbine with reaction blades with total of 27 stages divided to 7 cones. Designes of regulating stage and stage part were checked by calculation of tensile and bending stress. In next parts are calculations of compensating piston and turbine seal system, design of radial and thrust bearings and in the last chapter is shown consumption characteristics of turbine. The designed turbine after optimization at nominal condition has power of 55013,02 kW with thermodynamic efficiency of 83,06 %. The reheat factor of turbine is 1,063. The diploma thesis is supplemented by a conceptual sectional drawing of turbine.

The aim of this master´s thesis is to design solution of equipment for dividing rods of non-ferrous metals. The equipment is primarily meant for innovation of semi-finished product preparation in blacksmith's workshop. This master´s thesis mainly focused on design of individual mechanical components of alligator shears and their calculations. There are also solved dangerous places for operators and surroundings by using a safety analysis. The result of this master´s thesis is possibility of design mechanical part according to assignment.

The Wind Turbine industry continues to drive towards high market penetrationand profitability. In order to keep Wind Turbines in field for as long as possiblecomputational analysis tools are required. The open source tool QBlade[38] softwarewas extended to now contain routines to analyse the structural properties of WindTurbine blades. This was achieved using 2D integration methods and a Tapered Euler-Bernoulli beam element in order to find the mode shapes and 2D sectional properties.This was a key step towards integrating the National Renewable Energy LaboratoriesFAST package[32] which has the ability to analyse Aeroelastic Responses. The QFEMmodule performed well for the test cases including: hollow isotropic blade, rotatingbeam and tapered beam. Some improvements can be made to the torsion estimationof the 2D sections but this has no effect on the mode shapes required for the FASTsimulations.

Externally applied loads from high winds or impacts may cause structural damage to the wind-turbine blade, and this may further affect the aerodynamic performance of the blade. Wind-turbine blades experience high vibration levels or amplitudes under high winds. Vibrations negatively affect the wind flow on the blade. This project considers the structural dynamic analysis of a small-scale wind turbine with a particular focus on the blade; it involves the finite element model development, model validation and structural analysis of the validated model. The analysis involves a small-scale wind-turbine structural response when subjected to different loading inputs. The analysis is specifically focused on on-shore systems. The use of small-scale wind-turbine systems is common however, apart from initial structural analysis during design stages, these systems have not been studied sufficiently to establish their behaviour under a variation of real-life loading conditions. On-shore wind turbines are often designed for low-wind speeds and their structural strength may be compromised. In addition, these systems experience widely-varying wind speeds from one location to another to an extent that it is extremely difficult to achieve a uniform structural performance. The main reason for solving this problem is to evaluate the structural response of the blade, with special emphasis on an 800 W Kestrel e230i. This involves the calculation of the distribution of blade deflections and stresses over the wind-turbine blade under different loading conditions. To solve the problem, a three-dimensional model of a Kestrel e230i blade was firstly developed in Autodesk Inventor Professional using geometrical measurements that were taken in the mechanical engineering laboratory. A 3D finite element model was developed in ANSYS using approximate material properties for fiberglass obtained from the literature. The model was then validated by comparing its responses with those from a number of static tests, plus a simple impact test for comparison of the first natural frequency. Finally, a number of numerical tests were conducted on the validated finite element model to determine its structural responses. The purpose of the numerical analysis was to obtain the equivalent von Mises stress and deformation produced in the blade. It was determined that under the examined different loading conditions, a higher stress contour was found to occur around the mid-span of the blade. The calculated maximum flexural stress on the blade was observed to be less than the allowable flexural stress for fiberglass which is 1,770 MPa. As expected, the highest deformation occurred at blade tip. The first critical speed of the assembled three-bladed wind turbine was found to be at 4.3 rpm. The first mode shape was observed to be in the flap-wise bending direction and for a range of rotor speeds between zero and 608 rpm, three out of a total of five mode shapes were in the flap-wise bending direction. Future studies should address issues relating blade vibrations with generated power, validation of dynamic tests, fluid-structural interaction and introduction of bio-inspired blade system. Although the performance of the bioinspired blade has not been studied in great detail, preliminary studies indicate that this system has a superior performance. / Mechanical and Industrial Engineering / M. Tech. (Electrical and Mining Engineering)

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During the operation of a gas turbine, ingested contaminants present in the air form deposits on the surfaces of the turbine blades. These deposits grow over time, resulting in an increasingly rough surface. This gradual increase in roughness results in several negative consequences, among which is an increase in the rate of heat transfer to the blade which shortens blade life. This thesis presents research in which deposits were evolved on three different turbine blade coupons and their evolution was studied. A trend in roughness change over time was discovered. Also, an attempt was made to find the effect of the deposits on the heat transfer characteristics of a coupon surface. The deposits were formed using the BYU Turbine Accelerated Deposition Facility (TADF), which was used to simulate three months of deposition within a two hour test time. All three coupons underwent four cycles in the TADF: eight total hours of combustor testing—or one simulated year of deposition—with topological measurements being made on the coupon surface after every two hours (three simulated months) of testing. The data produced by the topological measurements were used with a CNC mill to machine scaled-up plastic models of the rough surfaces: four surfaces per model representing three, six, nine, and twelve simulated months of deposition. The models were placed in a wind tunnel where, following a period of thermal soaking at room temperature, they were suddenly exposed to a heated air stream. The thermal histories of the model were recorded with an infrared camera and were used to derive the heat transfer coefficient of each surface using the method developed by Shultz and Jones. The heat transfer coefficients are reported in the form of Stanton numbers to allow for the difference in thermal properties between the conditions and properties of the wind tunnel and its components and those of a real gas turbine. The Stanton numbers for the various surfaces were plotted versus the simulated gas turbine operational time. Additionally, several roughness correlations were used to predict the Stanton number for each surface, producing a probable Stanton number history for the coupon. The measured nondimensional heat transfer coefficients did not reach the magnitudes predicted by the correlations. This is most likely due to unexpected flow conditions inside the wind tunnel. Recommendations for future research are presented.

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