Health & Environmental Research Online (HERO)


Print Feedback Export to File
8217017 
Meetings & Symposia 
Preliminary shock-tunnel experiments on liquid fragmentation and atomization in hypersonic flows 
Schloeffel, G; Srulijes, J; Albers, H; Bastide, M; Rey, C 
2012 
ILASS � Europe, Institute for Liquid Atomization and Spray Systems 
12th International Conference on Liquid Atomization and Spray Systems, ICLASS 2012 
English 
The present work describes the objectives, the set-up and the preliminary results of an experimental study on the fundamental mechanisms of fragmentation and atomization of a bulk of liquid in hypersonic gas flows. Additionally, we introduce a former series of experiments and calculations also carried out at ISL. The current experiments are conducted by means of a horizontal shock tube which is operated as hypersonic wind tunnel (shock tunnel). The experimental set-up used is capable of reproducing conditions of real atmospheric flights from Mach 3 at ground-level conditions up to Mach 14 at a flight altitude of 70 km. This work focuses on shock tunnel experiments on the fragmentation and atomization of a bulk of liquid suddenly exposed to hypersonic atmospheric flow. The liquid substance to be studied is filled into a latex balloon which is placed in front of the shock tunnel nozzle. A needle driven by a magnetic mechanism pierces the balloon shortly before the nozzle flow sets-in, so that the bulk of liquid is introduced into the flow in an almost non-intrusive way. A first series of experiments at Mach 4.5 has been conducted with the help of a high-speed camera to observe the fragmentation of a bulk of 5 ml of water, ethanol and hexane at flight altitudes of 10, 20, 30 and 40 km. The analysis of the atomization and the evolution of the drop sizes require more sophisticated optical measurement techniques. Therefore, in a series of experiments already started a special Particle Image Velocimetry (PIV) technique is used to determine the velocity of the drops. A first result is presented in this paper. Beside this, a LIF-technique is being developed and adapted to observe the evolution of drop size and liquid evaporation. © ICLASS 2012 - 12th Inte. Con. on Liquid Atom. and Spray Systems. All rights reserved.