Transcript Portaferry
Efficiency Reflection Coefficent 1.2 1 0.8 0.6 0.4 0.2 0 0 1 2 R Z1 Z2 Z1 Z2 3 4 Damping ratio 5 Bearings SKF GX series Steel/PTFE Rolling bearings Dynamic rating Cdyn of a rolling bearing is the load that will probably start damage to 10% of a large population of bearings after one million rotations. Dynamic rating Cdyn of a rolling bearing is the load that will probably start damage to 10% of a large population of bearings after one million rotations. For balls the life increase is the load decrease raised to the power 3.0. Dynamic rating Cdyn of a rolling bearing is the load that will probably start damage to 10% of a large population of bearings after one million rotations. For balls the life increase is the load decrease raised to the power 3.0. For rollers the life increase is the load decrease to the power 3.3 Dynamic rating Cdyn of a rolling bearing is the load that will probably start damage to 10% of a large population of bearings after one million rotations. For balls the life increase is the load decrease raised to the power 3.0. For rollers the life increase is the load decrease to the power 3.3 Half load = 10 times life SKF say that only 1% of bearings fail for that reason. They now also quote a fatigue load for infinite life. Most fail because of their seals. Hydrostatic bearings Q = flow m3/sec h = slit gap P = Pressure N/m2 W = slit width d= pipe diameter S = triangle side L = length all in metres Flow through slit Q 3 P W h 12 L 4 Circular pipe Q P d 128 L 4 Triangle thread Q P S 185 L Viscous force F = Area . Velocity . Absolute viscosity gap But remember that viscosity is a strong function of temperature Special bearing Duck-to-spine bearing specification. Force in 10 metre htc wave = 30MN (3000 tonne) Duck-to-spine bearing specification. Force in 10 metre htc wave = 30MN (3000 tonne) Zero friction Duck-to-spine bearing specification. Force in 10 metre htc wave = 30MN (3000 tonne) Zero friction Infinite life Duck-to-spine bearing specification. Force in 10 metre htc wave = 30MN (3000 tonne) Zero friction Infinite life Working in sea water Duck-to-spine bearing specification. Force in 10 metre htc wave = 30MN (3000 tonne) Zero friction Infinite life Working in sea water 100 mm tolerance Duck-to-spine bearing specification. Force in 10 metre htc wave = 30MN (3000 tonne) Zero friction Infinite life Working in sea water 100 mm tolerance Diameter = 14 metre Length = 45 metre Duck-to-spine bearing specification. Force in 10 metre htc wave = 30MN (3000 tonne) Zero friction Infinite life Working in sea water 100 mm tolerance Diameter = 14 metre Length = 45 metre Pressure = 0.45 bar Power take off Pumps SECTION THROUGH POWER TORUS Motors Energy storage Gamma is ratio of specific heat at constant pressure/constant volume = 1.4 for diatomic gases eg nitrogen Ram control using digital hydraulics DOUBLE WALL ACCUMULATOR Air turbines Hydro Air Turbine Dresser Rand at All Energy 2011 The VRT design comprises two sets of static guide vanes located on either side and of a larger diameter than that of the rotor. These vanes are connected by a shaped duct to provide a route for the (inlet/outlet) airflow. Air enters the duct at a relatively low velocity and acquires a swirl motion as it passes through the inlet guide vanes. The air then accelerates as it passes down the narrowing duct towards the turbine rotor. The air drives the rotor, and then decelerates as it travels back through the expanding duct before passing over the outlet guide vanes. The process is repeated (in reverse) for the next wave cycle. In comparison with both Wells turbines and conventional impulse turbines, the HydroAir turbine solution offers a step-change in efficiency and operating range. The HydroAir turbine achieves its remarkable performance with fixed blade geometry, providing the reliability that is critical to the commercialisation of wave power.