A wave emulator for ocean wave energy, a Froude-scaled dry power take-off test setup

A dry laboratory environment has been developed to test Power Take-O_ (PTO) systems for Wave Energy Converters. The costs accompanied by testing a wave energy converter and its PTO at sea are high due to the di_cult accessibility of (remote) test locations. Next to easy accessibility, the lab setup provides controllable waves at a relatively lower cost. The setup enables extensive analysis of the dynamics of a PTO during its mechanical towards electrical energy conversion. The scaled setup is designed such that it resembles as close as possible the real system. Froudes similarity law provides easy transformation. The oater and waves are represented by a Wave Emulator, the motion of which is determined by a time series of the wave exciting forces supplemented with the actual hydrodynamic reaction forces due to the motions of the oater. A real-time calculation method is introduced, accounting for the actual PTO actions. Furthermore, the inertia of the oater is represented in the emulators rotary inertia, and a compensation method is proposed enabling an identical normalized PTO load curve as at full scale. Comparison between experimental and simulation results have been performed and good correlation between the movement of setup and simulations has been found

Farm Worker Killed When Caught in Power Take-off (PTO)

A 32-year-old male was killed when he was caught in a rotating power take-off (PTO) shaft. He had been involved in farming for many years and often helped his friends who owned a dairy farm. The farm worker was helping one of the owners of the farm load corn from the silage wagon into the feeding trough. Both the farm worker and the owner were experienced in operating the equipment on the farm and had worked together on this type of task before. However, the owner had always operated the equipment controls. The PTO connecting the tractor to the silage wagon was not covered by a safety guard. Recent heavy rains had made the area slick and muddy. The owner was nearby when he heard the victim yell; he found him wrapped around the rotating PTO. The farmworker suffered severe damage to the spinal cord, skull, and left leg, killing him immediately. In order to prevent similar incidents from occurring, FACE investigators recommend: PTO shafts should be covered by a protective guard Workers should avoid wearing loose or frayed clothing which can get caught in machinery Workers should be provided with training to safely operate equipmen

A power take-off and control strategy in a test wave energy converter for a moderate wave climate

The energy in the waves of oceans and seas can be converted to electricity by different types of Wave Energy Converters (WECs). Wave energy conversion is currently widely studied to contribute to the world’s rising energy needs. This paper describes a point absorber test WEC that was built for electrical energy production in moderate wave climates as can be found in the Belgian part of the North Sea. A robust design was put forward to assess the feasibility of a full electric rotational Power Take-Off (PTO) system. A stable reactive control algorithm was implemented to optimise the absorbed energy from the waves by tuning the natural frequency of the WEC towards the frequency of the waves. From simulations it is shown that also for real irregular waves, this tuning shows a significant beneficial effect on the absorbed energy. The control parameters for different wave conditions are discussed as well as the effect of the chosen PTO system and its constraints on the absorbed power and optimum control parameters

Design and Analysis of Power Take-Off (PTO) and Telescopic Driveshafts

Power take-off (PTO) is widely used in automotive field but not commonly known to most people. PTO and telescopic driveshaft systems are used to transmit power from the engine to external machinery. The PTO system used by Light Fire Rescue Tender (LFRT) manufactured by CME Technologies Sdn Bhd is not the best because it is assembled by three telescopic driveshafts instead of one. The aim of this project is to simulate and analyze the PTO and telescopic driveshafts on Light Fire Rescue Tender trucks to identify area for improvement. Subsequently, this project also attempts to suggest a new design to improve the performance of this system. In achieving the objectives, simulation and analysis of the existing system will be performed and recommendation of a new system which will enhance the performance of the system will be proposed. It is hoped that the Design and Development Division of CME Technologies Sdn Bhd will refer to this research after the completion of the project

Effect of Accessory Power Take-off Variation on a Turbofan Engine Performance

Engine fuel efficiency of aerospace vehicles can be reached by different techniques. One way to do that is to reduce aircraft subsystems power supply effects on the engine performance. Previous research work has showed that extracting bleed air from the high pressure compressor exit is more efficient than extracting the equivalent amount of energy from the low pressure spool shaft. A high bypass turbofan engine was modeled using the Numerical Propulsion System Simulation (NPSS). The baseline engine performance was evaluated at different flight conditions of Mach number and altitude. To better understand the effect of air bleed take-off and shaft power extraction, four simulation cases are investigated at constant fuel flow and constant high pressure turbine inlet temperature setting. The first two cases extract bleed air from compressors while the last two cases extract equivalent power from engine shafts. Appropriate model modifications and port connections are made to consider the power extraction method. The effect of a bleed air fraction off-take from 1% to 10% and equivalent shaft power extraction on engine performance of thrust and thrust specific fuel consumption was investigated. Engine compressors operating lines and HPT inlet temperature were also checked. Results proved that shaft power extraction is more efficient for engine performance than bleeding an equivalent air fraction from compressors. Those results were shown to be consistent with a simulation run on the AEDsys simulation tool

Power take-off simulation for scale model testing of wave energy converters

Small scale testing in controlled environments is a key stage in the development of potential wave energy conversion technology. Furthermore, it is well known that the physical design and operational quality of the power-take off (PTO) used on the small scale model can have vast effects on the tank testing results. Passive mechanical elements such as friction brakes and air dampers or oil filled dashpots are fraught with nonlinear behaviors such as static friction, temperature dependency, and backlash, the effects of which propagate into the wave energy converter (WEC) power production data, causing very high uncertainty in the extrapolation of the tank test results to the meaningful full ocean scale. The lack of quality in PTO simulators is an identified barrier to the development of WECs worldwide. A solution to this problem is to use actively controlled actuators for PTO simulation on small scale model wave energy converters. This can be done using force (or torque)-controlled feedback systems with suitable instrumentation, enabling the PTO to exert any desired time and/or state dependent reaction force. In this paper, two working experimental PTO simulators on two different wave energy converters are described. The first implementation is on a 1:25 scale self-reacting point absorber wave energy converter with optimum reactive control. The real-time control system, described in detail, is implemented in LabVIEW. The second implementation is on a 1:20 scale single body point absorber under model-predictive control, implemented with a real-time controller in MATLAB/Simulink. Details on the physical hardware, software, and feedback control methods, as well as results, are described for each PTO. Lastly, both sets of real-time control code are to be web-hosted, free for download, modified and used by other researchers and WEC developers