Jeffrey Bennett

Case Study: Dynamic Analysis of a Novel Vertical Axis Wind Turbine

An analytical model was developed for the dynamic evaluation of a novel vertical axis wind energy system. This study was conducted early on in the design process, so the goal was to create a low level tool to determine if the concept was feasible, to perform initial sizing of the turbine, to better understand the behavior of the unique furling mechanisms, and to predict the performance. In order to prevent damage at high rotational speeds, the novel concept integrates passive mechanisms into a drag driven vertical axis wind turbine with the intention that blades furl out of the wind once a critical wind speed is reached, and passively reopen. Established wind turbine aeroelastic codes were unable to represent this unique system, therefore, a standalone analytical model was developed in Python. A Lagrangian approach was taken to represent the interactions of the system’s degrees of freedom. To complete the model, mathematical representations of the furling mechanisms and interaction of the wind on the blades was developed. Basic structural calculations were also included to determine the initial size of the primary mechanical components. This case study focuses on the development of the low-level dynamic model and shares several results of the expected behavior.Copyright

Simulator To Train Operators On Newly Installed Pumping Equipment

New screw pumps were installed at an existing offshore oil platform that originally housed only centrifugal pumps, thus creating the need to safely train operators on the new equipment. Therefore, a training simulator was developed with control screens identical to those provided by the manufacturer providing a safe and low-cost way for training operators. The simulator was designed with the ability to control the entire pumping system, so that any operating scenario could be created in addition to the preloaded cases. Screens were added to provide insight into the operating behavior of the system and to allow the chance to try alternative operating procedures. The simulator developed provides a means for the platform operators to comply with API 1120, ASME B31Q, RP 1161 and RP T-2. This paper will focus on describing the need for creating a training simulator, the approach to creating the simulator, will present some example screenshots, and present the system insight that is gained by allowing operators to learn about the system hydraulics.

Quick Method for Aeroelastic and Finite Element Modeling of Wind Turbine Blades

In this paper a quick method for modeling composite wind turbine blades is developed for aeroelastic simulations and finite element analyses. The method reduces the time to model a wind turbine blade by automating the creation of a shell finite element model and running it through a cross-sectional analysis tool in order to obtain cross-sectional properties for the aeroelastic simulations. The method utilizes detailed user inputs of the structural layup and aerodynamic profile including ply thickness, orientation, material properties and airfoils to create the models. After the process is complete the user has two models of the same blade, one for performing a structural finite element model analysis and one for aeroelastic simulations. Here, the method is implemented and applied to reverse engineer a structural layup for the NREL 5MW reference blade. The model is verified by comparing natural frequencies to the reference blade. Further, the application to aeroelastic and structural evaluations is demonstrated. Aeroelastic analyses are performed, and predicted fatigue loads are presented. Extreme loads from the aeroelastic simulations are extracted and applied onto the blade for a structural evaluation of the blade strength. Results show that the structural properties and natural frequencies of the developed 5MW blade match well with the reference blade, however the structural analysis found excessive strain at 16% span in the spare caps that would cause the blade to fail.Copyright