Semester of Graduation
Master of Science in Mechanical Engineering (MSME)
Mechanical and Industrial Engineering
In the testing of today’s rocket engines, both on large scale vertical test stands and smaller subscale horizontal component testing stands, it is extremely important to be able to accurately quantify and mitigate the thermal and acoustic loads the engines will generate on test stand infrastructure. Due to the large number of parameters that must be considered for many cases, development of a multi-phase computational code is under way to properly analyze and design water spray cooling systems used at NASA’s Stennis Space Center (SSC) and across other NASA centers. As such, a small-scale experiment has been conducted at Louisiana State University to provide experimental results which can be used to inform the development and verify the validity of such a code, and allow for several important physical characteristics of liquid breakup phenomena to be examined. The interactions of free jet of compressed air and varied coherent liquid jet injection parameters and nozzle sizes are examined and compared to the traditional problem of jet in cross flow (JICF). Non-intrusive diagnostic tools are used to examine the behavior of the internal shockwave structure in the overexpanded gas jet with and without liquid injection and significant changes are seen for varied injection location not seen for traditional JICF. An extension of the regime map for primary liquid breakup is made and high-speed imaging shows that for varied injection pressure the primary breakup regime of the liquid jet is similar to what is expected from literature. As the liquid jet is able to influence the momentum of the gas jet, an examination of the average spray boundary location and droplet size measurements in the secondary breakup region show significant flow turning of the gas phase and a strong dependence on the relative size of each fluid jet not accounted for in traditional JICF. Progress towards implementation of a hybrid rocket engine is also presented as next steps for better matching test conditions at SSC.
Jones, Hansen, "Liquid Jet Penetration and Breakup in a Free Supersonic Gas Jet" (2018). LSU Master's Theses. 4817.