SuperGen UK Centre for Marine Energy Research Progress Meeting 2018 Extreme loads and survivability Cameron Johnstone, Stephanie Ordonez-Sanchez, Song Fu and Rodrigo Martinez Energy Systems Research Unit, University of Strathclyde, Glasgow, UK
Activities Undertaken: Tidal Energy Numerical modelling work: 1. Hydrodynamic loading on composite blades 2. Evaluating the dynamics of mooring lines in tidal stream turbines Experimental work: 3. Loading of tidal turbine blades when subjected to wave-current interactions
1 Hydrodynamic loading on composite blades 1. Run BEMT model with desired parameters. 2. Use the inflow magnitude and angle of attack at each blade element as input to a series of 2D CFD models of the blade section. 3. Combine the output pressure distributions from the 2D CFD models into a 3D model using interpolation function in MATLAB. BEMT-2D-CFD model developed to obtain pressure distribution across blade Blade element Pressure points from 2D CFD
1 Hydrodynamic loading on composite blades Verification of an ANSYS model based on experimental static analysis 1m carbon fibre blade subjected to a number of loading cases Differences between experimental tests and Ansys model below 5%
1 Hydrodynamic loading on composite blades
Thrust (N) 1 Hydrodynamic loading on composite blades BEMT model for time series loading in current and random waves at elements along blade radius for input to Ansys fatigue modelling 18000 16000 14000 12000 10000 8000 6000 4000 2000 0 20 70 120 Time (s) r=1.712 5m r=3.412 5m r=5.537 5m r=7.662 5m r=9.787 5m Hollow blade with structural support under a regular wave case of wave height 2.6 m and wave period 6.1s
1 Hydrodynamic loading on composite blades Hollow blade with structural support under a extreme wave case: wave height 10.1 m and wave period 10.06 s
1 Hydrodynamic loading on composite blades Advantages of thermoplastic resins: Improve seawater saturated properties and a higher percentage recovery of mechanical properties upon being dried after saturation Recyclable at the end of their lives and have reduced manufacturing cycle times, energy requirements, and manufacturing costs. Demonstration blades manufactured using an infusible thermoplastic resin system called Elium mold infusion process final blade 3D-printed mold, middle) infusion process for blade skin and final blade design To investigate the structural reliability of the thermoplastic composites at a small-scale, the blade was analysed using ANSYS. Initial Ansys design on the 400 mm long blade
Relative Velocity Modification 2 Evaluating the dynamics of mooring lines in tidal turbines Forces on the buoy Net Buoyancy Wave Excitation and Drift Force Drag Force Added Mass In house BEMT code Wave- Current Model BEMT Equations Dynamic Wake Model Morison Equation m1 = 1t, m2 = 5t, m3 = 80t, l1 = 30m, l2 = 15m l3 = 3m, turbine diam = 20m, depth = 50m current speed = 2:5m/s r = 1.25rad/s R = 3m NRELs814
2 Evaluating the dynamics of mooring lines in tidal turbines T=6.135s H=4.322m Thrust and Torque r= 3m v=2.5m/s Regular steep wave, wave period 6.13 s and wave height 4.32 m The wave excitation on the buoy will not increase the peak thrust loads on the mooring supported turbine in this sea state compared to the rigid foundation, but will increase the load dispersion. This means that the wave excitation on the buoy is an important factor in fatigue analysis.
2 Evaluating the dynamics of mooring lines in tidal turbines T=11.07s H=1.07m Thrust and Torque r= 3m v=2.5m/s Swell wave, wave period 11.07 s and wave height 1.07 m By taking into account the wave excitation on the buoy, it is noticeable a reduction of the peak loads on the turbine.
Extreme wave, wave period 10.06 s and wave height 10.12 m The reduction in torque and thrust is visible for the mooring supported turbine when including the wav excitation on the buoy. The relative velocity generated by the relative motion between the turbine and wave-current in the vertical direction damps the effect of the extreme wave. 2 Evaluating the dynamics of mooring lines in tidal turbines T=10.06s H=10.12m Harsh Winter r= 3m v=2.5m/s
3 Array testing of tidal turbines Objectives of the test campaign Tests to carry out in March 2019 at FloWave Ocean Energy Research Facility Three turbines to be deployed in the facility In collaboration with Cardiff University through the Dylotta project
Ongoing and further work 1. Structural analysis using ANSYS composite Pre-post (ACP) 2. Develop the mooring line model to a four pendulum system in order to investigate the dynamics of the turbine during operation 3. Compare systems of different natural frequency in order to conclude the effect of wave excitation on the buoy accurately Submitted and published work 1. Fu, S., Johnstone, C. M. Evaluating the Dynamics of Mooring Tidal Turbines. Naples: 13th European Wave and Tidal Energy Conference. Abstract invited for full paper submission 2. Murray, R., Ordonez-Sanchez, S., Fu, S., Trubac, K., O Doherty, T., Johnstone, C. Modeling and manufacturing of a thermoplastic carbon-fiber tidal turbine blade. Naples: 13th European Wave and Tidal Energy Conference. Abstract invited for full paper submission 3. Murray, R. E., Ordonez-Sanchez, S., Porter, K. E., Doman, D. A., Pegg, M. J., & Johnstone, C. M. (2017). Towing Tank Testing of Passively Adaptive Composite Tidal Turbine Blades and Comparison to Design Tool. Renewable Energy (under review). 4. Fu, S., Johnstone, C. M (2018) A Sea-state Based Investigation for Performance of Submerged Tensioned Mooring Supported Tidal Turbines. Taipei: 4th Asian Wave and Tidal Energy Conference.
Questions? Contact details Stephanie Ordonez-Sanchez: s.ordonez@strath.ac.uk Song Fu: song.fu@strath.ac.uk Rodrigo Martinez: r.martinez@strath.ac.uk Cameron Johnstone: cameron.johnstone@strath.ac.uk