The vortex tube is a simple device that is capable of separating a flow into two streams with different temperatures. Despite its simplicity, the thermal-fluid behavior of the vortex tube remains a subject of considerable controversy. The recirculating, compressible, highly swirling flow within a vortex tube is difficult to model. Accurate experimental measurements of the internal distributions of temperature, pressure, and velocity are not available because conventional measurement techniques such as invasive probes or flow visualization using seeding particles are not effective in this environment.
A non-invasive laser technique that does not require particle seeding has been designed. The technique is based on chromatic analysis of laser light scattered by the gas itself. The focus of this project will be the development of this technique. Initial experimental results will be compared with measurements using conventional flow visualization techniques under benign, benchmark flow conditions in order to verify the technique. The internal distribution of temperature, pressure, and velocity in a vortex tube will subsequently be measured.
This work will produce two significant results. First, the experimental measurements will provide vortex tube data of unprecedented detail and accuracy, revealing the processes that govern its unique behavior. Second, a powerful, non-invasive technique for obtaining detailed measurements in complex flows will be developed and demonstrated. The measurement technique promises to be useful in other areas such as turbomachinery.
The award has been funded by the Thermal Transport and Thermal Processing Program of the Chemical and Transport Systems Division.
