The anti-suck-back ability of five new high-speed air turbine handpiece models was evaluated in this study. First, suck-back pressure with water displacement within a glass tube was measured. Next, under three different conditions, how many on-off times it takes before fluorescent stains became visible on a piece of gauze at the exhaust vent was counted and the presence of fluorescent stains on...

Inadequate design and improper mixing operation in anaerobic digesters often lead to poor mixing and digester failures due to the presence of dead zones formed in the digester. More research is required to understand the mixing phenomena in anaerobic digesters and thus improve their efficiency. This paper investigates the efficiency of mixing of digester sludge in a mechanically agitated vessel...

A computational fluid dynamics simulation is done for non-Newtonian fluid in a baffled stirred tank. The CMC solution is taken as non-Newtonian shear thinning fluid for simulation. The Reynolds Average Navier Stocks equation with steady state multi reference frame approach is used to simulate flow in the stirred tank. The turbulent flow field is modelled using realizable k-ε turbulence model. T...

The ability to monitor the structural health of the rotating components, especially in the hot sections of turbine engines, is of major interest to the aero community in improving engine safety and reliability. The use of instrumentation for these applications remains very challenging. It requires sensors and techniques that are highly accurate, are able to operate in a high temperature environ...

Complex three-dimensional vortex flows develop at the junction of a gas turbine airfoil and its casing (endwall). These flows increase the transfer of heat from the combustion gases to the metal parts and contribute to reduced aerodynamic efficiency. Past studies have shown that the use of a large fillet at the airfoil-endwall junction can reduce or eliminate the endwall vortex flow pattern. To...

Predictive modelling of turbulent combustion is important for the development of air-breathing engines, internal combustion engines, furnaces and for power generation. Significant advances in modelling non-reactive turbulent flows are now possible with the development of large eddy simulation (LES), in which the large energetic scales of the flow are resolved on the grid while modelling the eff...

Up-down counters are commonly used in the aerospace industry for fault detection thresholding. This paper applies the up-down counter technique to detect wind turbine faults. The thresholding problem involves a tradeoff between false alarms and missed detections. Counter based thresholding can detect smaller faults with higher probability and lower false alarms than is possible using simple con...

We developed a computational model based on a finite-element mixed formulation with quadratic isoparametric beam elements. We applied this model to the analysis of a blade-wagon: a novel structure characteristic of an innovative concept in wind-power called VGOT Darrieus turbine. We studied the structural behaviour of its main components: chassis, suspension and blade, using combinations of bea...

In this work, multiple model control of a boiler-turbine system is studied. Multiple linear local models are obtained through piecewise linearization. A bank of Kalman filters is constructed using these local models. States and model parameters used for future predictions within the predictive control are updated online through computation of probability density functions. Simulations show that...