Closed-Loop Thrust and Pressure Profile Throttling of a Nitrous Oxide/Hydroxyl-Terminated Polybutadiene Hybrid Rocket Motor

Author

Zachary W. Peterson, Utah State University

Date of Award:

12-2012

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Mechanical and Aerospace Engineering

Committee Chair(s)

Stephen A. Whitmore

Committee

Stephen A. Whitmore

Committee

R. Rees Fullmer

Committee

David K. Geller

Abstract

Hybrid motors that employ non-toxic, non-explosive components with a liquid oxidizer and a solid hydrocarbon fuel grain have inherently safe operating characteristics. The inherent safety of hybrid rocket motors offers the potential to greatly reduce overall operating costs. Another key advantage of hybrid rocket motors is the potential for in-flight shutdown, restart, and throttle by controlling the pressure drop between the oxidizer tank and the injector. This research designed, developed, and ground tested a closed-loop throttle controller for a hybrid rocket motor using nitrous oxide and hydroxyl-terminated polybutadiene as propellants. The research simultaneously developed closed-loop throttle algorithms and lab scale motor hardware to evaluate the fidelity of the throttle simulations and algorithms. Initial open-loop motor tests were performed to better classify system parameters and to validate motor performance values. Deep-throttle open-loop tests evaluated limits of stable thrust that can be achieved on the test hardware. Open-loop tests demonstrated the ability to throttle the motor to less than 10% of maximum thrust with little reduction in effective specific impulse and acoustical stability. Following the open-loop development, closed-loop, hardware-in-the-loop tests were performed. The closed-loop controller successfully tracked prescribed step and ramp command profiles with a high degree of fidelity. Steady-state accuracy was greatly improved over uncontrolled thrust.

Checksum

25a0716923de7585eacdcbd65f2461c1

Comments

This work made publicly available electronically on December 21, 2012.

Recommended Citation

Peterson, Zachary W., "Closed-Loop Thrust and Pressure Profile Throttling of a Nitrous Oxide/Hydroxyl-Terminated Polybutadiene Hybrid Rocket Motor" (2012). All Graduate Theses and Dissertations, Spring 1920 to Summer 2023. 1400.
https://digitalcommons.usu.edu/etd/1400