Presenter Information

Trevor Coombs, Utah State University

Class

Article

College

College of Engineering

Department

Mechanical and Aerospace Engineering Department

Faculty Mentor

Stephen Whitmore

Presentation Type

Poster Presentation

Abstract

A hybrid rocket motor's ability to throttle and restart, along with other desirable traits, drives its potential to be an emerging technology in spaceflight applications. However, the current lack of an ability to maintain an optimal mixture ratio of oxidizer to fuel propellants, O/F ratio, during combustion limits the hybrid motor's overall efficiency. This study quantifies how variations in O/F ratio and combustion chamber pressure, which a throttle valve can indirectly manipulate upstream of the chamber, affect the characteristic velocity (c * ) and specific impulse (Isp) of the motor. The researcher uses an analytical hybrid rocket combustion model and experimental results involving hybrid rockets of different diameters and lengths to produce the data used in this study. The researcher meshes the results of these two efforts into one comprehensive report. This becomes a useful guide when attempting to maximize the c * and Isp of a throttleable hybrid rocket in relation to a range of different O/F ratios and rapid changes in chamber pressure.

Location

Logan, UT

Start Date

4-12-2023 2:30 PM

End Date

4-12-2023 3:30 PM

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Apr 12th, 2:30 PM Apr 12th, 3:30 PM

Relating Throttled Hybrid Motor Performance to Oxidizer-to-Fuel Ratio

Logan, UT

A hybrid rocket motor's ability to throttle and restart, along with other desirable traits, drives its potential to be an emerging technology in spaceflight applications. However, the current lack of an ability to maintain an optimal mixture ratio of oxidizer to fuel propellants, O/F ratio, during combustion limits the hybrid motor's overall efficiency. This study quantifies how variations in O/F ratio and combustion chamber pressure, which a throttle valve can indirectly manipulate upstream of the chamber, affect the characteristic velocity (c * ) and specific impulse (Isp) of the motor. The researcher uses an analytical hybrid rocket combustion model and experimental results involving hybrid rockets of different diameters and lengths to produce the data used in this study. The researcher meshes the results of these two efforts into one comprehensive report. This becomes a useful guide when attempting to maximize the c * and Isp of a throttleable hybrid rocket in relation to a range of different O/F ratios and rapid changes in chamber pressure.