From blood flow through artificial heart valves to mixing and combustion of fuel and air in a modern jet engine, many flows are both unsteady and three-dimensional. Modern diagnostics used to study, test and evaluate these flow fields, however, are slow and two-dimensional or, in the case of multi-camera 3D diagnostics, expensive and complex. In this project, the research team will develop a new imaging system capable of making high-speed 3D measurements in practical flow fields using only a single camera. The developed system will be significantly cheaper, more compact, and easier to set up than complex multi-camera systems, thus providing researchers around the world with an accessible and affordable tool to make high-speed 3D flow measurements. This imaging system will be used to understand cardio- and cerebro-vascular flows, advance high speed vehicle design research, and improve combustion efficiency in engines and combustion systems for power generation. In addition, the technology developed here will be openly shared with the broader research community to ensure access for students and researchers across the U.S. government agencies and industries. Such wide distribution ensures that the developed system impacts the widest possible range of applications involving unsteady, 3D fluid flows.
The basis for this diagnostic is an intensified plenoptic imaging system capable of measuring 3D scalar and velocity fields at framing rates in excess of 1,000 frames per second. The system consists of three essential elements: (1) a kHz rate intensified plenoptic camera and illumination source optimized for 3D flow measurements; (2) image reconstruction and velocity estimation algorithms to render volumetric images and estimate velocity fields; and (3) a computing platform that processes the data in an acceptable time frame. The development of this system will enable time-resolved, 3D flow measurements, including particle image velocimetry, chemiluminiscence imaging, laser induced fluorescence, and background oriented Schlieren imaging. The proposed instrument is based on a low frame-rate prototype built by investigators at Auburn University that has been demonstrated as a simple, compact, robust and effective 3D imaging system. The modularity of the system will allow the system to be optimized for different facilities and techniques, including stereo-plenoptic diagnostics with the potential to dramatically improve spatial resolution of volumetric measurements.
