Effects of Diameter and Orientation On Multiphase Flow Patterns

Advances in avionics and weaponry are leading to higher thermal loads for next generation military aircraft beyond what traditional PAO coolant loops can handle.  One proposed solution is to use a phase change fluid to capture the additional heat. 

Due to fluctuating orientation and heat load transient modeling is critical.  As a first step, the focus of this work is to demonstrate the effects of diameter (3/8” through 2” pipe) and orientation on flow patterns observed visually and identified through capacitance methods.