Capstone Design – Hybrid Rocket: Oxidizer Feed System

Joshua Laas

About MeB.S. Mechanical Engineering – June 2016 graduate from Oregon State University, GPA 3.43I am a highly motivated, newly graduated student, seeking a career in the aerospace industry. I have dedicated my senior year of college to studying courses that focus entirely on aerodynamic design. I have been involved in the design of OSU’s first hybrid rocket. I was the technical lead for the rocket’s oxidizer feed system and was in charge of ensuring all calculations were accurate and concepts within the design were applicable. I am a quick learner and love teaming up with others to accomplish something new and innovative. My objective is to work in a progressive environment that encourages technical and creative growth.

Project Overview• Sponsored by OSU Chapter of AIAA

(American Institute of Aeronautics and Astronautics)

• Design and build a flight-viable hybrid rocket• Perform both ground and flight tests• Research and optimize for the future• Collaborative design experience• Designs intended for 2017 Hybrid Rocketry

Competition

Multidisciplinary Collaboration

Fuel and Energetics – 4 Chemical Engineers• Fuel composition

optimization• Combustion reaction

energetics

Data Acquisition – 3 Electrical Engineers• DAQ system for propulsion

test stand

bbc.co.uk

Hybrid Rocket Design – 12 Mechanical Engineers

● Hot End 1 - injector, fuel, igniter● Hot End 2 - combustion chamber, injector

manifold, nozzle● Cold End - oxidizer feed system, remote

priming system● Vehicle Engineering - recovery system,

aerodynamics, structures, integration

Launch Rail – 3 Mechanical Engineers

● Large enough for hybrid rocket

● Collapsible for travel

Overall Design Process

House of Quality:

CRs and ESs

Simulation:SolidWorks

ANSYSOpenRocketNASA CEA

EES

Sub-system testing:Sub-team

TPs

Full-scale testing:Test firesDry Run

Assemblies

Oxidizer Feed System

Overview• Driving CRs

– Safe pressurization– Non-corrosive– High Isp

• Proposed problems– Safety– Spatial constraints– Acceptable pressure &

mass flow rate • Subsystem solutions

– Oxidizer/pressurant– Feed system

components– Remote oxidizer

priming

Oxidizer/Pressurant• Nitrous Oxide

– Non-cryogenic– Common – Non-toxic – Easy storage – Better performance– Cooling

• Self-pressurizing– No pressurant– Acceptable pressures– Single tank

Feed System Components • Single tank configuration

– Lightweight – Smaller size

• Servo actuated ball valve– 45 kg-cm servo– 3/8” ball valve– Opens completely in 0.15 s– Mass flow up to ~0.66 kg/s– Operated remotely by on-board microcontroller

Feed System Components Cont. • Stinger

– Unobstructed line extending from inside the tank at desired fill level to an exit through the side of the rocket body

– A 3/16” tube is welded into a drilled out hex plug. Through the remaining 1/8” wall, a 0.016” orifice is drilled in the hex nut and a 3/16” tube is welded to the non-threaded side to guide the vented gases out of the body of the rocket

– When the oxidizer is filled to the desired level, the bleed line will begin venting liquid, signaling fill completion

– Empties tank of foreign gas– Adiabatic expansion prevents supercritical

temperature

Remote Oxidizer Priming• Collapsible arm

– Hydraulic quick-disconnect fittings

– Worm drive and gear motor

– Servo to initiate an electronic disconnect

– 316 Stainless steel• Accessibility

– Side of rocket– Magnetic door

Results Passed: 10 out of 12 testing proceduresFailed:

Specific Impulse Performance TestTarget: 221-270 sAchieved: 210 s

Reason: Ambient temperature of 56℉ during test, optimal oxidizer temperature between 70 and 74℉.

Oxidizer Tank Pressure TestTarget: 760-1500 psiAchieved: 550 psi

Reason: Ambient temperature of 56℉ during test, optimal oxidizer temperature between 70 and 74℉. Oxidizer storage tank was unable to self-pressurize to 760 psi.

RecommendationsFor better results:• Test rocket motor vertically• Use double valve carbon fiber

tank• Pressurize with inert gas• Decrease plumbing pressure drop

– Test larger check valve• Temperature control storage tank

For ease of data analysis:• Ensure all sensors work for every

test• Advance method for cleaning up

data• Create a venturi flow meter

https://www.youtube.com/watch?v=ZyfvJF529no

For safety: • Keep impressing other hybrid teams by

enhancing existing safety mechanismshttp://www.simmonsmfg.com/wp-content/uploads/2012/11/PAGE-5-CC1b.jpg

LaunchSuccessful launch on July 3, 2016 in Brothers, OR. The rocket flew to an altitude of 5,342 feet and was recovered safely.

Further ExplorationOSU Hybrid Rocket Facebook:https://www.facebook.com/OSUhybridrocketclub/photosOSU Hybrid Rocket Test Videos: https://www.youtube.com/channel/UCENvX7uhVTVMby8BE_YOu9whttps://www.youtube.com/watch?v=flaiKnyUY0E LinkedIn:https://www.linkedin.com/in/joshua-laas-23871511b