Aerospace Engineering Brown Bag Lecture Series, Robert Clark and Christopher Douglas .

The September 24th Aerospace Engineering Brown Bag Lecture Series featured, Robert Clark and Christopher Douglas .
Robert Clark presented,
"Design and Analysis of an Aircraft Thermal Management System Linked to a Low Bypass Ratio Turbofan Engine"
The success of future military aircraft depends greatly on their ability to dissipate the extreme thermal loads that are associated with the advanced weaponry and electronic systems onboard these aircraft. A design was developed for an aircraft thermal management system (TMS) capable of meeting these heat dissipation demands and rejecting heat loads into the bypass stream of a typical low-bypass ratio turbofan engine, or a ram-air stream. This presentation will discuss the design of the TMS system and how it was linked to the engine, and a comparison will be shown between the cooling capabilities of the ram-air stream versus the engine bypass stream, along with the benefits and drawbacks of each cooling stream. The ability of a sized TMS to reject the demanded aircraft loads throughout several key off-design points will be shown, along with the impact of engine bleeds on engine thrust and fuel consumption. The presentation will also discuss next steps for this research, most notably the need to develop variable cycle engine models.
Christopher Douglas presented,
"Dynamics of Laminar Swirling Jets"
Even the simplest swirling jet flows possess an astonishing degree of complexity. This complexity is a two-edged sword, presenting both a unique opportunity to advance the science of fluid mechanics as well as a major barrier for a variety of engineering applications. Swirling jet technologies have proven crucial for enabling the increased efficiencies and drastically reduced emissions seen in modern combustion systems. However, the enhanced mixing and flame stability characteristics offered by swirling flow configurations are constrained by a relatively limited understanding of their dynamics, which continues to press the power and propulsion industry against the limits of reliable performance. In this work, the behavior of laminar swirling jets is considered from a dynamical systems perspective using bifurcation analysis. These results offer several new insights into the key physics of swirling jets, such as demonstrating bistability between competing low-pressure regions and characterizing the bifurcations and nonlinear dynamics of a variety of coherent limit-cycle structures from an initially steady state.