Embedded Instrumentation for Detection of Flow Separation

Statement of the Problem: The applicant is a global leader in marine renewable energy technology and a developer of eco-conscious projects that harness the power of oceans and rivers to generate clean, predictable renewable energy. Our technology is based on crossflow turbines which are advantageous in rivers and shallow tidal estuaries. However, the performance of crossflow turbines is analytically complex and cannot be predicted with standard turbine design tools due to unsteady flow separation and reattachment occurring within each rotation. This inability to precisely predict hydrodynamic loading hinders the ability to design with minimal material usage, thereby increasing system cost. General Statement: The applicant will work with a university to develop a novel pressure sensing system to aid in the understanding of the flow physics involved in crossflow turbine operation, allowing for optimized turbine hydrodynamic and structural design. The sensing technology will enable a predictive maintenance approach, which will limit cumulative damage to systems in operation, and allow for planned replacement or repairs of systems. What is to be done in Phase I: The university will develop a flexible, ultra-thin sensing technology enabling the lamination of pressure sensors onto a turbine. The sensor will be designed for the dynamic pressures of the helical bladed crossflow turbine. The sensor array will be tested in a water flume at various speeds for a simple geometry to enable validation. The response of the sensor will allow extraction of the transient response including attenuation and phase shift. Commercial Applications & other benefits: The ability to measure time-resolved and localized pressure and shear stress on moving blades has been long desired in the aerodynamics community. The development and proving of the proposed robust pressure sensing technology will allow for validation of various aerodynamic and hydrodynamic analytical models and provide insight into flow separation behaviors which are at present, analytically intractable. The integration of this sensor technology with applicantĺs crossflow turbine will allow for optimized turbine hydrodynamic and structural design. The sensing technology will also enable a prognostic health monitoring system, leading to a pro-active maintenance program driven by operational data. Predictive maintenance will lower operating expenses for projects, improve availability, and lower the Levelized Cost of Energy. The sensing technology has other high value applications which are commercially significant, including wearable pressure monitoring and robotic sensing.