High-Pressure Combustion of HAN-Based Monopropellants
Open Access
- Author:
- Chai, Nicholas
- Graduate Program:
- Mechanical Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- May 31, 2023
- Committee Members:
- Robert Kunz, Professor in Charge/Director of Graduate Studies
Richard A Yetter, Thesis Advisor/Co-Advisor
Jacqueline Antonia O'Connor, Committee Member - Keywords:
- Hydroxylammonium Nitrate
HAN
High-Pressure Combustion
High Pressure
HAN-MeOH
13M HAN
Critical Combustion
Real Gas Model
Closed Bomb Testing - Abstract:
- Previous studies of hydroxylammonium nitrate (HAN)-based mixtures are limited to low to moderate pressures (< 20 MPa). This study extends the understanding of a HAN-methanol (MeOH) and HAN-water (13M HAN) mixture at high pressures. Throughout this study, the burning rate, surface structure, and reaction zone temperature were found to change. Pressure regimes were identified where the burning rate of the monopropellant was highly pressure dependent, resulting in a burning rate nearly an order of magnitude lower than at other pressures. Both monopropellants had a similar burning rate trend from 30 to 131 MPa, which could imply that this behavior is due to the shared reactants: HAN and water. Often, points of significant burning rate variations were accompanied by changes in turbulent flow structure. The onset of these behavioral changes is theorized to be due to reaching a critical point of the propellants. Pseudocritical calculations considering HAN decomposition aligned well with a transitional point for HAN-MeOH, but not 13M HAN. However, at 70 MPa, both propellants shared a local minimum burning rate, which resembled the behavior of HAN-MeOH, where the pseudocritical results indicated a critical point. Therefore, this could possibly be another critical point of the mixtures, but current assumptions in the pseudocritical calculations do not account for real gas effects or for the presence of diffusion of species to and from the surfaces.