Mechanical Engineering


Mathematics ; Robotics


Nassersharif, Bahram

Advisor Department

Industrial and System Engineering


Phelps, Peter




Naval; Submarine; Launcher; Projectile; Phase; Design

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 4.0 License.


JOHNNY MOLLOY (Mechanical Engineering) Ambient Temperature Phase Change Launcher Sponsor: Bahram Nassersharif (Mechanical Engineering)

Deployment of payloads stored in watertight cylindrical bodies in underwater environmental conditions are of interest to the marine and naval community. The proposed work will investigate the possibility of using inert carbon dioxide gas compressed into its liquid state and stored under pressure to launch payloads by means of expansion from a cylindrical tube. To suit the needs of the Naval Undersea Warfare Center (NUWC), this launching system must fire from up to 14 ft underwater, have two degrees of freedom, and the payload must not exceed an acceleration of 8g upon launch. To accomplish this, the team went through an expansive design process that originated with a highly regulated non-direct launching system. After initial testing, the team revised its design to feature a more direct launch, eliminating unnecessary components such as a solenoid valve and other connections that ultimately choked the flow of the carbon dioxide gas and decreased its pressure and effectiveness on the projectile. After redesigning the projectile, launch tube and overall assembly, tests were conducted to record the new projectile’s average velocity and acceleration. These tests were also conducted through a column of water to test the launcher’s effectiveness in a naval application. A market analysis and demand forecast were performed for this design, as well as a financial analysis that shows a significant increase in profit margins with high production volume. Using a simple force equation, a first order Euler simulation was performed that calculated important values such as acceleration, drag force, and frictional losses at each time step of the projectile’s motion. These calculations verified the initial design specifications for the launcher, in which the projectile can be fired from up to 14 feet underwater with a CO2 pressure constraint of 800 psi, all while not exceeding 8g’s of acceleration.

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