The primary goal of the this paper is to summarize field demonstrations of the feasibility of detecting changes in blade and shaft natural frequencies (such as those associated with a blade or shaft crack) on operating machinery using non-contact, nonintrusive measurement methods. This paper primarily addresses the results of application of this nonintrusive torsional vibration sensing to: a la...

Wind turbines reliability is affected by stochastic factors in the turbulent inflow and wind turbine structures. On one hand, the variability in wind dynamics and the inherent stochastic structures result in random loads on wind turbine rotor and tower. On the other hand, the inherent structural uncertainties caused by imperfect control of manufacturing process introduce unpredictable failures ...

1. Turbine Classification 1.1. Blade Profiles 1.2. Impulse and Reaction 2. Velocity Diagrams 2.1. General Relationships 2.2. Momentum Principle 2.2.1. Impulse Blading 2.2.2. Reaction Blading 2.3. Blade Efficiency 2.4. Energy Principle 2.4.1. Impulse Blading 2.4.2. Reaction Blading 2.5. Impulse Blading 2.6. Reaction Blading 2.7. Whirl Velocity 3. Stage Design 3.1 Number of Stages 3.1.1 Impulse B...

This paper studies the relationship between unsteady flow features and instantaneous torque and power performance of straight bladed vertical axis wind turbine at variable tip speed ratios. The rotor unsteady flow field simulation was carried out by using computational fluid dynamics method. The flow physics and the principle of changing flow filed acting on torque performance and power perform...

An experimental campaign of measurements for a Darrieus vertical-axis wind turbine (VAWT) is presented for open field conditions. The turbine is characterized by a twisted bladed design, each blade being placed at a fixed distance from the rotational shaft. The experimental setup to perform the acquisitions is described. The results are lower than expected, due to the high influence of the wind...

The wind force on turbine blades, consisting of a drag and lift component, depends nonlinearly on the relative wind velocity. This relative velocity comprises mean wind speed, wind speed fluctuations and the structural response velocity. The nonlinear wind excitation couples the flap wise and edge wise response of a turbine blade. To analyze this motion coupling, an isolated blade is modelled a...

There is a growing interest in design and manufacturing of micro-heat exchangers embedded in turbine blades of the jet engine for turbine blade cooling. The pertaining manufacturing technologies fall under micro-meso manufacturing, including subtractive methods, additive methods, and near net shaping methods. The purpose of this paper is to provide an overview of micro-meso manufacturing method...

Significance of the Problem Control of blade-tip clearance in the compressor and turbine sections of gas turbine engines can improve efficiency, minimize leakage flow, and shorten engine development time. Tip clearance varies throughout different operating conditions (e.g., start-up, idle, full power, shut-down) because of different radial forces and different thermal expansion coefficients and...

The emergence of wind turbine systems for electric power generation can help satisfy the growing global demand. To maximize wind energy captured in variable speed wind turbines at low to medium wind speeds, a robust control strategy is presented. The proposed strategy simultaneously controls the blade pitch and tip speed ratio, via the rotor angular speed, to an optimum point at which the effic...