טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentSetter Avishay
SubjectA Study of the Performance and Combustion Characteristics of
a Rocket Motor Employing Solid Propellant Enriched
with Liquid Oxidizer
DepartmentDepartment of Aerospace Engineering
Supervisor Professor Emeritus Alon Gany
Full Thesis text - in Hebrew Full thesis text - Hebrew Version


Abstract

In this a study a method of producing a consolidated solid propellant grain enriched with liquid oxidizer was developed, and thereafter a solid rocket motor was designed in order to conduct a comparative performance evaluation of said propellant.

Solid propellant rocket motors constitute the vast majority of rocket motors in most applications. The main advantage of solid propellant rockets lies in the simplicity of their design, which principally includes only a combustion chamber and a nozzle, as compared to liquid propellant rockets which require in addition storage tanks for the propellant materials, a system for pumping and injecting the propellants as well as nozzle and chamber cooling  systems, which greatly complicate the design and as a result increases its inert mass fraction and design and production costs, while reducing reliability. The main disadvantage of solid propellant rockets is their inferior performance in comparison to liquid rockets. While the specific impulse of solid rockets is in the range of 200-270 seconds, liquid rocket propellants utilizing cryogenic propellant can exceed 400 seconds.

The main reason for the relatively low performance of solid propellants stems from the fact that solid oxidizers are generally less energetic than liquid propellants. Thermochemical simulations of different propellant compositions show that the specific impulse of the most common solid propellant can be increased by up to 20% for non-aluminized propellants, and up to 12% for aluminized propellants by replacing the solid oxidizer with a liquid oxidizer.

This study aims to examine a novel idea of integrating a storable liquid oxidizer into a solid propellant grain. The study included the development of a solid propellant grain which contains small diameter tubes containing gelled liquid oxidizer. Subsequently, a lab scale solid rocket motor was designed and manufactured, and series of static fire tests was conducted with said propellant. The performance of the new hybrid propellant was compared to a standard solid propellant under the same operation conditions.

Results show that the solid propellant that was enriched with gelled liquid oxidizer demonstrated higher specific impulse, characteristic velocity and burn rate as compared to a standard solid propellant.