Self-pressurizing propellant tank dynamics
Abstract/Contents
- Abstract
- Hybrid rockets frequently use nitrous oxide as a self-pressurizing oxidizer, where the high vapor pressure of the oxidizer is used to force the liquid out of the propellant tank and into the combustion chamber. To study this system, a series of small-scale pressure vessels with optical access have been developed that can be filled with nitrous oxide and then drained in a manner that replicates the conditions within a hybrid rocket. A high-speed camera has been used to visualize the nitrous oxide within the propellant tank and identify relevant phenomena. Experiments have identified two separate temporal regimes that are common to all blowdown tests: a transient and steady state, each described by distinct features. The transient regime is characterized by a rapid pressure drop and recovery, with homogeneous condensation of the ullage and heterogeneous nucleation and growth of bubbles. During steady state regime the liquid and vapor are both homogeneous two-phase mixtures and the pressure drops in a linear fashion as the liquid drains from the tank. Carbon dioxide was identified as a possible simulant fluid for nitrous oxide, and comparison tests showed that it behaves as an accurate analog. This low-cost and safe simulant fluid enabled a large number of tests that examined the effect of parameter variations, including flow rate, fill level, temperature, and scaling effects. Experimental data from this system have been used to develop a new model for self-pressurizing propellant tank dynamics. This was done by blending the 0-D lumped-node methods of previous researchers with a novel 1-D method that captures the dynamics of a changing bubble population. The direct quadrature method of moments was used to develop partial differential equations for parameters of this distribution. The proposed model was compared against experimental data and shown to have good agreement. The pressure drop and recovery seen in the transient regime, which is not captured by previous models, is visible in the model predictions. Convergence studies were performed in order to determine suitable parameters of the numerical integration schemes and the discretizations used. To complete the model, numerous submodels were incorporated by using relations from various sources in the literature. The effect of variations in these submodels was studied in order to justify the selection of adjustable constants.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2015 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Zimmerman, Jonah E |
|---|---|
| Associated with | Stanford University, Department of Aeronautics and Astronautics. |
| Primary advisor | Cantwell, Brian |
| Thesis advisor | Cantwell, Brian |
| Thesis advisor | Alonso, Juan José, 1968- |
| Thesis advisor | Zilliac, Gregory G |
| Advisor | Alonso, Juan José, 1968- |
| Advisor | Zilliac, Gregory G |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Jonah E. Zimmerman. |
|---|---|
| Note | Submitted to the Department of Aeronautics and Astronautics. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2015. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2015 by Jonah Earl Zimmerman
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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