Analysing the performance of the Archimedes screw turbine within tidal range technologies

The UK has an enormous potential for tidal range energy. With the threat of global warming and the decline of the North Sea oil industry, national energy focus is shifting towards this form of renewable energy. Following in the footsteps of the first tidal barrage scheme in La Rance, the 320MW Swansea bay lagoon scheme has recently been given governmental approval (BBC News, 2015). Like existing projects, this lagoon will use the bulb turbine, which has been the standard device for tidal range projects for the last 50 years. One of the reasons these have continued to be chosen is because they are a proven technology, however, since the first project in the 1960’s, turbine technologies have evolved and altered in a plethora of new designs. The aim of this research is to investigate and evaluate these new designs numerically using a marking criteria to determine their suitability. Out of the designs examined the Archimedes Screw proved the most promising for further research, due to the reduced cost, simplistic design and environmentally friendly nature. Through the use of computational fluid dynamics (CFD), a variety of screw turbine designs were evaluated, each investigating a different geometric parameter, which affects the overall performance of the device. The trends found due to altering these values proved that the design of a screw turbine and a screw pump are fundamentally different. The designs, which both increased the volume of flow in each screw bucket and decreased the surface area of the turbine in contact with the flow proved the best. This device in tidal lagoons offers; superior pumping ability; longer operational per tide cycle and can perform well in water with a high silt content (which is expected in tidal lagoons). However, it is necessary to perform further research and model testing to fully analyse the power potential of a full sized device

Over 2000 years in review:revival of the Archimedes screw from pump to turbine

The Archimedes pump is one of the oldest feats of engineering still being used today. In recent times, it has seen a major revival in modern engineering, by reversing it for use as a turbine. This is now an established turbine, being used in Europe since 1994. It has been found this new turbine device has a plethora of advantages over current existing devices, with the simplicity and robustness that has kept the pump in use for centuries acting in its favour. Most existing design theory is for use as pump; however there are many key differences between operation as a pump or turbine, such as the direction the water flows through the device. With further research for turbine operation alone required. The Archimedes Screw turbine currently has a variety of operational modes: inclined, horizontal or submerged. These new devices have the possibility to unlock a wide range of applications. The submerged tidal stream device can operate in low flow velocities (1m/s)that current devices are unable to. The inclined and horizontal turbines offer greatly reduced environmental effects and can be used in areas previously passed over because of delicate habitats. However, there are still more potential uses, for example in tidal range or tidal fence situations, although research for use in these methods are currently only in the initial stages with Computational Fluid Dynamics (CFD) simulations and scale modelling required to prove the validity

A world first:Swansea Bay Tidal lagoon in review

Global energy focus is turning more and more towards renewable energy. With legally binding agreements requiring a drastic increase in the percentage of national energy demand created with renewable sources, tidal energy holds an important advantage – predictability. The UK is fortunate, having the greatest potential for this energy in the world, which if exploited, would be able to provide approximately 20% of the national energy demand. The most discussed tidal energy site has been the Severn estuary barrage, with repeated proposals outlined and rejected throughout the last 100 years. The reasons for this refusal were due to both high costs and environmental concerns. However, a new proposal for a tidal lagoon in Swansea Bay has been able to circumnavigate both of these downfalls by reducing both the investment needed and effects to the surrounding environment. Subject to a tidal range of 10.5 m and situated next to a largely populated city with excellent grid connections, Swansea bay is a perfect location. If the lagoon project goes ahead, it would be able to produce a rated output of 320 MW using bulb turbines, powering 155,000 homes. Being the first tidal lagoon project, what is certain is: the UK and Wales in particular are sending out a strong message regarding renewable energy and it has the whole worlds attention. This paper sets out to bring together current literature regarding the planned Swansea Bay tidal lagoon into one concise document

Tidal range technologies and state of the art in review

Tidal range technology has seen much development and interest in recent years. The times when a barrage scheme would be rejected due to environmental and cost concerns is coming to an end. A large variety of new lower cost and less invasive methods have since emerged in the forms of tidal lagoons, reefs and fences. Since the construction of La Rance in 1967, advancements in turbine technologies and design has since resulted in a plethora of new, exciting turbine designs for tidal energy. A selection of new turbines with possible tidal range applications includes the modified bulb turbine with two sets of guide vanes, a counter-rotating turbine, Archimedes screw and a gyro device. However, the same design is continuously being chosen – the Kaplan bulb turbine. Through the use of a marking criterion covering key aspects that should be considered when choosing a turbine a variety of the new designs available are investigated. The key aspects researched include, environmental effects, the two-way efficiency, initial costs and maintenance costs/difficulty

Burkholderia multivorans septicemia in a pediatric liver transplant patient

“Cepacia syndrome”, caused by Burkholderia cepacia complex and often associated with cystic fibrosis, carries a high mortality rate. It is rare for Burkholderia multivorans, a species within the B. cepacia complex, to cause cepacia syndrome even among patients with cystic fibrosis. This is the first reported fatal case of cepacia syndrome caused by B. multivorans occurring in a pediatric liver transplant recipient who does not have cystic fibrosis. We describe the unique characteristics of this pathogen among the non–cystic fibrosis population and the importance of early recognition and treatment

Burkholderia multivorans septicemia in a pediatric liver transplant patient

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148247/1/ajt15065_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148247/2/ajt15065.pd