Online

Smith, Silas F.

Mechanical Engineering

2013

MS

Inductively Coupled Plasma (ICP) facilities create high enthalpy flows to recreate atmospheric entry conditions. Although no condition has been duplicated exactly in a ground test facility, it is important to characterize the condition to understand how close a facility can come to doing so. An lCP facility was constructed at the University of Vermont for aerospace material testing in 2010. The current setup can operate using air, carbon dioxide, nitrogen, and argon to test samples in a chamber. In this work we investigate different ways to increase measured heat flux and expand our facility to operate supersonically. To do so, a water cooled injection system was designed to overcome failure points of the prior system. An investigation of heat flux methods that provide a baseline for the facility were also examined and tested. A nozzle configuration was also developed with an overall goal of increasing the plasma flow to reach sonic and supersonic velocities, allowing it to be compared with the existing subsonic system.
An iterative approach was taken to develop a nozzle design that is robust enough to handle the harsh environment, yet adaptable to the pre-existing facility components. The current design uses interchangeable sonic and supersonic nozzles which also allow for appropriate plasma gas expansion. Data are taken through retractable and goose-neck probe sample holders during testing. Heat flux can be determined by use of a Gardon gage, slug calorimeter, and water cooled calorimeter. Total and static pressure are determined from a pitot tube and pressure tap, which are then manipulated into a velocity measurement. A comparison between subsonic and supersonic operation is then made with these data. Existing literature uses correlations between jet diameter and velocity gradients to determine the effective heat flux. This investigation found that the experimental and theoretical heat flux results scale correctly according to the correlations.