A STUDY ON THE ATOMIZATION AND SPRAY CHARACTERISTICS OF GELLED SIMULANTS FORMED BY TWO IMPINGING JETS
Open Access
- Author:
- Fakhri, Syed Abdul Khader
- Graduate Program:
- Mechanical Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- None
- Committee Members:
- Richard A Yetter, Thesis Advisor/Co-Advisor
Jongguen Lee, Thesis Advisor/Co-Advisor
Richard A Yetter, Thesis Advisor/Co-Advisor - Keywords:
- GHP
Hypergolic
Proplellants
Gelled Hypergolic Propellants
Atomization
Spray
Nozzle
Sheet
Simulant
Nozzle Jet - Abstract:
- The atomization mechanism of Gelled Hypergolic Propellants (GHPs) in an impinging jet flow field is significantly different from that of non-gelled liquid propellants and is not clearly understood. In this study, rheologically matched non-Newtonian fluids which are non-reactive and non-toxic were used to act as a simulants for the gelled hypergolic propellants. A Newtonian fluid has been used as a simulant for liquid propellants and to act as a comparison standard for the non-Newtonian simulants. This study explored the effect of nozzle geometry such as orifice inlet shape and aspect ratio on the jet stream surface dynamics and the break up process before and after doublet jet impingement, respectively. Gels produced, using polymer or particle gellants, displayed less disturbed surfaces than non-gelled fluids, due to increased viscosity. As a result, for a given flow rate the sheet formed by impinging jets was much more stable and the sheet break up length was greater for gelled-water than non-gelled water jets. The nozzle aspect ratio has more noticeable effects on the near-field jet stream characteristics for both fluids than the orifice inlet shape. The longer nozzles form a more stable jet stream which delays the break-up of the sheet, leading to greater break up lengths than the shorter nozzles. For similar Reynolds number, droplet size for gelled water is much smaller than that for non-gelled water. Also, impinging jets employing gelled water produce sprays which are distributed over a wider space and in a wider range of droplet sizes than the jets with non-gelled water.