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Atomization and Sprays

Journal of the International Institutes for Liquid Atomization and Spray Systems

ISSN for PRINT: 1045-5110

Institutional price:	$787.00
Issues per year:	8

Best Paper Award Selection - Editorial Board Site

2003, Volume13

211 pages

DOI: 10.1615/AtomizSpr.v13.i56

Issue price - $150.00

GENERATION AND SHOCK WAVE CHARACTERISTICS OF UNSTEADY PULSED SUPERSONIC LIQUID JETS

K. Pianthong
School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, Australia; Department of Mechanical Engineering, Faculty of Engineering, Ubonratchathani University, Ubonratchathani, Thailand

Brian E. Milton
Computational Fluid Dynamics Research Laboratory, School of Mechanical and Manufacturing Engineering, The University of New South Wales; Faculty of Engineering, University of Technology Sydney, Sydney, Australia 2052

Masud Behnia
School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney 2052, Australia

ABSTRACT

One method for generating pulsed, supersonic liquid jets is by projectile impact, often referred to as the "Bowden-Brunton" method. In this article, the fundamental processes by which such jets are generated are investigated. The momentum transfer from the projectile to the liquid and the shock wave reflection within the nozzle cavity are the key items of interest. In this study, a new one-dimensional analysis has been used in order to simplify this complex and difficult problem. First, the impact pressure obtained from the projectile is derived. Then, an investigation of the intermittent pressure increase in both a closed end cavity and a simple stepped, cross-sectional nozzle cavity (sac) is carried out. The nozzle pressure and final jet velocity are estimated and compared with experimental results, with which they show good agreement, and to a previous analytical method. Also, experimental shadowgraph visualization of the jet penetrating the air is presented. Some interesting characteristics, such as a rippled leading edge main (bow) shock wave in the air and the appearance of a second shock wave, can be seen. These characteristics relate well to those anticipated by the analysis.