Nozzle erosion in hybrid rocket motors

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Nozzle erosion in hybrid rocket motors is an unsolved and generally unstudied problem that poses a hurdle to small-scale and long-burning hybrid rocket motor development. While the nozzle erosion problem has been studied extensively in liquid rocket engines and solid rocket motors, it has remained largely untouched for the hybrid rocket configuration. In this research, nozzle erosion is measured in a small lab-scale motor utilizing gaseous oxygen and paraffin wax as propellants at various chamber pressures and oxidizer to fuel (O/F) ratios. Paraffin-based fuels are of particular interest as they are inert and have proven high-performance capabilities. An ultrasound sensor along with an array of thermocouple sensors are placed at the nozzle throat plane of the motor and the combination of the recorded data allows for the reconstruction of the time-varying wall thickness at the throat plane. This data is used to determine nozzle erosion, as well as a time varying estimate of the inner wall heat flux at the nozzle throat plane. While the nozzle erosion data is the primary interest for this study, other researchers may find the heat flux estimations useful as they can be used in the validation of CFD models. A dimensionless model is then proposed to capture the affects of O/F ratio, chamber pressure, nozzle material properties, flame temperature, efficiency, and mixing. This dimensionless model can be used to estimate nozzle erosion for any given hybrid rocket motor design, which should be useful to hybrid rocket motor designers.


Type of resource text
Form electronic; electronic resource; remote
Extent 1 online resource.
Publication date 2016
Issuance monographic
Language English


Associated with Narsai, Pavan
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 Close, Sigrid, 1971-
Advisor Alonso, Juan José, 1968-
Advisor Close, Sigrid, 1971-


Genre Theses

Bibliographic information

Statement of responsibility Pavan Narsai.
Note Submitted to the Department of Aeronautics and Astronautics.
Thesis Thesis (Ph.D.)--Stanford University, 2016.
Location electronic resource

Access conditions

© 2016 by Pavankumar S Narsai
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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