This experimental study contains two points; part1 – turbine blade heat transfer under low Reynolds number flow conditions, and part 2 – trailing edge cooling and heat transfer. The effect of unsteady wake and free stream turbulence on heat transfer and pressure coefficients of a turbine blade was investigated in low Reynolds number flows. The experiments were performed on a five blade linear cascade in a low speed wind tunnel. A spoked wheel type wake generator and two different turbulence grids were employed to generate different levels of the Strouhal number and turbulence intensity, respectively. The cascade inlet Reynolds number based on blade chord length was varied from 15,700 to 105,000, and the Strouhal number was varied from 0 to 2.96 by changing the rotating wake passing frequency (rod speed) and cascade inlet velocity. A thin foil thermocouple instrumented blade was used to determine the surface heat transfer coefficient. A liquid crystal technique based on hue value detection was used to measure the heat transfer coefficient on a trailing edge film cooling model and internal model of a gas turbine blade. It was also used to determine the film effectiveness on the trailing edge. For the internal model, Reynolds numbers based on the hydraulic diameter of the exit slot and exit velocity were 5,000, 10,000, 20,000, and 30,000 and corresponding coolant – to – mainstream velocity ratios were 0.3, 0.6, 1.2, and 1.8 for the external models, respectively. The experiments were performed at two different designs and each design has several different models such as staggered / inline exit, straight / tapered entrance, and smooth / rib entrance. The compressed air was used in coolant air. A circular turbulence grid was employed to upstream in the wind tunnel and square ribs were employed in the inlet chamber to generate turbulence intensity externally and internally, respectively.

Mass transfer experiments were conducted to study the thermal performance characteristics of blockages with round and elongated holes, positioned in a 12:1 rectangular channel. Naphthalene sublimation technique was adopted to conduct experiments with four different blockage configurations, flow rates corresponding to Reynolds numbers (based on channel hydraulic diameter) of 7,000 and 17,000, and at three blockage locations. The hole area to channel area ratio for all four blockage configurations was the same at 0.196. The hole width was half the channel height, and the distance between consecutive blockages was twice the channel height. Average heat transfer, local heat (mass) transfer and overall pressure drop results were obtained. The thermal performance for a particular blockage configuration was measured in terms of the heat transfer enhancement and the friction factor ratio. Heat transfer enhancement was measured as a ratio of average Nusselt number on the blockage surface to the Nusselt number for a thermally fully developed turbulent flow in a smooth channel. Results indicate that this ratio ranged between 3.6 and 12.4, while the friction factor ratio varied between 500-1700. The blockage configuration with round holes was found to yield best thermal performance, while the configuration with largest hole elongation was nearly equal in thermal performance. In order to compare different blockage configurations, an average value of upstream and downstream side thermal performances was used. A general downward trend in Nusselt number ratio with elongation of holes was observed on the upstream side and a reverse trend was observed on the downstream side. An upward trend in the Nusselt number ratio with blockage hole elongation on the downstream side of a blockage was primarily due to jet reversal from the downstream blockage and its impingement on the downstream surface of the upstream blockage. Local experiments were performed to compare against the results from average experiments and also to gain insights into the flow behaviour. There was good agreement between the results from local and average mass transfer experiments. The average variation in Nusselt number ratio between local and average mass transfer experiments was about 5.06%.

This study presents a novel polyimide-based self-assembly three dimensional micro blade using surface micromachining technology for the development of micro-fan chip. The high surface-tension-force of reflowed polyimide has can be used to lift the free-standing micro blade. In addition, the thesis introduces a micro hinge structure to effectively limit the maximum lifting angle of the micro blade and to accurately lock hinge-pin into the vertical position. Many parameters have been investigated its influence on the surface-tension- force of polyimide, including the thickness of polyimide and the temperature/time in reflow processing. Based on the experimental results, 18 £gm-thick polyimide can lift the micro blade at 70¢X angle under 380 ¢J/10 hrs reflow condition. On the other hand, 25 £gm-thick polyimide has demonstrated its maximum lifting angle can be achieved to 130¢X utilizing the very high surface-tension-force induced by over contraction and deformation when it was reflowed at higher temperature (400 ¢J). Finally, this dissertation has studied the relation between the position of polyimide elastic-joint and the deflection angle (£r). Furthermore, this thesis has successfully demonstrated a novel multi-joint and asymmetrical microstructure for the development of the spiral and out-of-plane 3D micro blade.

This thesis investigates the relations between (1) free stream velocity, blade radius as well as the number of blades, and (2) generated torque, power and efficiency in the design of a water turbine. In the study, blade element momentum theory (BEMT) is exploited to devise the shape of the horizontal water turbine. Further, a CFD package is in used to simulate the flow and pressure fields. The result shows that torque and power generated by turbine vary with such parameters as inlet velocity and blade radii. As the number of blade increases, the generated power is also on the rise but to a lessened degree.It is due to the fact that fluid can hardly flow into the cross section as the blade number increases, which brings about lower cross-section velocity. So the rotational speed should decline as a consequence to obtain the angle of attack satisfying the greatest lift-drag ratio. The largest power efficiency is thus gained.

This dissertation describes the design, analysis and testing of an unconventional rotor featuring extremely flexible, retractable blades. These rotor blades are composed of a flexible matrix composite material; they are so flexible that they can be rolled up and stowed in the rotor hub. The motivation for this study is to equip the next generation of unmanned rotary-wing vehicles with morphing rotors that can change their diameter in flight, based on mission requirements. Due to their negligible structural stiffness, the static and dynamic behavior of these blades is dominated by centrifugal effects. Passive stabilization of the flexible blades is achieved by centrifugal stiffening in conjunction with an appropriate spanwise and chordwise mass distribution. In particular, such blades are susceptible to large deformations. For example, a combination of the trapeze effect and the tennis racquet effect induces a large negative twist that results in decreased efficiency. Additionally, the rotor blades are prone to aeroelastic instabilities due to their low rotating torsional frequency, and it is seen that without careful design the blades experience coupled pitch-flap limit cycle oscillations. The primary focus of this research is to develop analytical and experimental tools to predict and measure the deformations of an extremely flexible rotor blade with non-uniform mass distribution. A novel aeroelastic analysis tailored towards unconventional blades with negligible structural stiffness is developed. In contrast to conventional analyses developed for rigid rotor blades, the present analysis assumes very large elastic twist. The nonlinear coupled equations of motion for the flap bending, lead-lag bending and torsion of an elastic rotating blade are derived using Hamilton's principle. The virtual work associated with unsteady aerodynamic forces in hover is included in the analysis. An ordering scheme consistent with the relevant physical quantities is defined and terms up to second order are retained in the Hamiltonian. The equations of motion are solved using a nonlinear finite element analysis. The steady-state deformation of the rotor blade is obtained from the time invariant part of the solution. The rotating flap, lag and torsional frequencies are found by solving the eigenvalue problem associated with the homogeneous system of equations. Finally, stability boundaries are computed for various operating conditions and the influence of parameters such as rotational velocity and collective pitch angle is discussed. The analytical predictions are validated by experimental measurements of the blade deformation in hover. These measurements are obtained by a novel, non-contact optical technique called three-dimensional Digital Image Correlation (3D DIC). The use of this technique is demonstrated for the first time to obtain full-field deformation measurements of a rotating blade. In addition, stability boundaries are extracted from experimental observations and correlated with predictions. / text

Computations and experiments were run to study adiabatic effectiveness and thermal field contours for a simulated turbine blade leading edge. The RKE and SST k-[omega] turbulence models were used for the computational simulations. Predictions of RKE model for laterally averaged adiabatic effectiveness matched the experimental values. The computational simulations showed different flowfield for the coolant exiting the stagnation line row of holes. Both the experiments and SST k-[omega] simulations predicted coolant separation at the stagnation plane. Also, the downstream spreading of the coolant exiting the stagnation row of exit holes was better predicted by the SST k-[omega] model. At the stagnation plane, experimental thermal field measurements showed greater diffusion of the coolant into the mainstream than predicted by both turbulence models. Reasons for increased diffusion were examined. Thermal field comparison downstream of the offstagnation row of exit holes showed that the computational simulations and the experiments had the same general shape for the offstagnation coolant jet. But the computational simulations predicted greater diffusion of coolant in the direction normal to the surface than seen in the experiments. / text

Reducing tillage in Canadian organic cropping systems is a priority to preserve soil quality and increase long term sustainability. Novel methods for management of cover crops offer farmers the opportunity to reduce both tillage and herbicide use during this phase of the crop rotation but require further investigation across a range of cropping systems. The objective of this study was to compare the blade roller, flail mower and wide blade cultivator (noble blade) with standard tillage for management of an annual pea-barley (Pisum sativum L. – Hordeum vulgare L.) green manure in the Canadian prairies. The experiment was conducted twice at Carman, Manitoba (long-term organic management) and Lethbridge, Alberta (previous herbicide and fertilizer use) from 2010-2012. The green manure was planted in spring of year 1 and grown until pea full bloom when five management treatments were applied; 1) standard tillage with a field disc 2) blade roller, 3) blade rolled once plus tillage in late fall and spring, 4) wide blade cultivator and 5) flail mower. Spring wheat (Triticum aestivum L.) was planted in spring of year 2. The effect of management treatment on surface residue, soil nitrogen, soil microclimate, weed population dynamics and subsequent spring wheat yield was evaluated. At Carman, managing green manure without tillage (blade roller or flail mower) significantly increased winter annual and perennial weed pressure and reduced soil nitrate availability; these factors contributed to wheat yield reductions in both years compared to standard tillage. Wide blade cultivation and blade rolling plus tillage maintained crop yield at one and both years, respectively, compared to tillage. Without sufficient mulch for weed suppression, soil disturbance was required to control weeds and ensure adequate nitrogen uptake in the crop. Replacing one tillage operation with blade rolling reduces energy costs and erosion risk without sacrificing yield. At Lethbridge, previous herbicide and fertilizer use masked the effect of green manure management. Markedly different results from Carman and Lethbridge emphasize that the adaptability of reduced tillage green manure management is site-specific due to differences in climate and cropping history. This research highlights important differences in the efficacy, erosion risk, weed control, nitrogen availability, main crop yield and energy savings associated with each management method.

The objective of this study was to investigate the effects of using the blade roller for no-till/reduced tillage in organic green manure management. The study was conducted in Carman, Manitoba and Oxbow, Saskatchewan. In the spring, a pea/oat intercrop was seeded as a green manure. The green manure was terminated by rolling, tilling, or a combination of the two. The following spring, spring wheat was seeded. In the year of the green manure, measurements taken included: biomass, soil nitrogen, and ammonia emissions. In the year of the wheat, measurements taken included: soil cover, soil moisture, weed competition, soil nitrate-N, and wheat biomass. Results showed increased soil cover, minimal effect on soil moisture, delayed wheat development, an effect on weed communities, reduced rate of nitrogen release, and reduced wheat yield. No-till green manure management can therefore provide benefits of soil conservation and nitrogen conservation but may result in decreased wheat yield.

Due to more and more aggressive designs in turbomachinery, assuring the structural integrity of its components has become challenging. Also influenced by this trend is blade design, where lighter and slimmer blades, in combination with higher loading, lead to an increased risk of failure, e.g. in the form of blade vibration. Methods have been proposed to reduce vibration amplitudes for subsonic engines, but cannot directly be applied to transonic regimes due to the additional physical phenomena involved. Therefore the present work investigates numerically the influence of two methods for reducing blade vibration amplitudes in transonic turbomachines, namely varying the blade count ratio and clocking. As it is known that clocking affects the efficiency, the concurrent effects on vibration amplitudes and efficiency are analyzed and discussed in detail. For the computational investigations, the proprietary Fortran-based non-linear, viscous 3D-CFD solver VolSol is applied on two transonic compressor cases and one transonic turbine case. In order to reduce calculation time and to generate the different blade count ratios a scaling technique is applied. The first and main part of this work focuses on the influence of the reduction techniques on aerodynamic forcing. Both the change in blade count ratio and clocking position are found to have significant potential for reducing aerodynamic force amplitudes. Manipulation of the phasing of excitation sources is found herein to be a major contributor to the amplitude variation. The lowest stimulus results are achieved for de-phased excitation sources and results in multiple blade force peaks per blade passing. In the case of blade count ratio variation it was found that blockage for high blade count ratios and the change in potential field size have significant impacts on the blade forcing. For the clocking investigation, three additional operating points and blade count ratios are analyzed and prove to have an impact on the force reduction achievable by clocking. The second part of the work evaluates the influence of clocking on the efficiency of a transonic compressor. It is found that the efficiency can be increased, but the magnitude of the change and the optimal wake impingement location depend on the operating point. Moreover it is shown that optimal efficiency and aerodynamic forcing settings are not directly related. In order to approximate the range of changes of both parameters, an ellipse approximation is suggested. / <p>QC 20130911</p> / TURBOPOWER

A limited and extendable master thesis is representing the first step in the experimental substructuring of an A600 wind turbine. Additional masses have been designed, manufactured and added to the sub components for the laboratory experimental tests. Further preparations for dynamic experimental tests have been described and implemented. Vibrational tests of a modified wind turbine blade have been made using the Leuven Measurements System (LMS) for excitations and data acquisition purposes. The theory of frequency response function based substructuring applied on the wind turbine blade model is demonstrated. The theory and an example of a Matlab coded spring-mass system, an experimental model of a wind turbine blade and FRFs stemming from measurements are reported.