Recent Results on Thread Formation with an Impinging Jet Injector

The formation of thread-like structures instead of droplets was observed during the injection process of distinct gel fuels and non-Newtonian fluids with an impinging jet injector. The objective of the present paper is to contribute to a better understanding of the mechanisms leading to the formation of these structures. Tests with many different Boger fluids have been conducted. To analyze the obtained shadowgraph images of the sprays a graphical analysis method was implemented. This code determines the thread parameter, a number that is associated with an average dimension of the threads. A correlation can be observed between the fluid relaxation time and the thread parameter. On the other hand, shear viscosity and surface tension do not seem to have an influence on thread formation