Date of Award


Document Type

Dissertation - Open Access

Degree Name

Doctor of Philosophy in Aerospace Engineering


Aerospace Engineering

Committee Chair

Dr. Yechiel Crispin

First Committee Member

Dr. Reda Mankbadi

Second Committee Member

Dr. Lakshmanan Narayanaswami

Third Committee Member

Dr. Eric Perrell

Fourth Committee Member

Dr. William Engblom


With the recent progress made in the field of space tourism, hybrid rocket engines have gained a renewed interest due to their simplicity, low cost, operational flexibility, and safety. The flow in the ports of a hybrid rocket motor involves several coupled unsteady phenomena like moving walls, combustion in a boundary layer flow and mass addition along the port, through the regression of the solid fuel wall. The flow in the combustion chamber of a hybrid rocket is inherently unsteady because the geometry of the port varies as a function of space and time. In the current research, we develop an unsteady generalized one-dimensional model of the compressible flow in order to predict the variation of the flow properties and the regression of the solid fuel as a function of time and the axial coordinate along the port. The resulting governing equations are first solved for the steady-state and are compared to Computational Fluid Dynamics results. Once the steady-state model is validated, then the partial differential equations are solved that has space and time coordinates. This model helps to introduce time-dependent non-acoustic instabilities into the system through the injector and the oxidizer mass flow rate. The unsteady results are compared with the experimental values and the current model predicts the flow behavior accurately.