Team 18: Design Optimization of a Supersonic Nozzle

Marc LinaresProject Coordinator

Alessandro Ciampitti Optimization Engineer

Marco RobainaCFD Engineer

Advisor: Prof. George S. Dulikravich

Design Optimization of a Supersonic Nozzle

http://www.colorado.edu/MCEN/cmes/czajkowski/gallery/slender_0.075_density.png

De Laval nozzle

Convergent Section Throat Divergent Section

M < 1 M = 1 M > 1

Timeline for Presentation

• Problem Statement

• Applications

• Optimization Goals

• Design Considerations

• Software Methods

• Manufacturing

• Validation

• Project Timeline

• Conclusion

Problem Statement

➢Non-uniformities of the flow at the nozzle exit due to upstream conditions & gradients

o Pressureo Temperatureo Densityo Speed

➢Shock wave development inside nozzle o Difference of inlet stagnation pressure and exit pressure

Applications

Rocket Propulsion Wind Tunnel

http://tfm.usc.edu/uploads/articles/6711/img_6347_sp12_b-crop__full.jpg http://www.coe.montana.edu/me/faculty/george/The%20SWT%20story_rev01_files/image006.jpg

Motivation

➢ Supersonic wind tunnel test facilities improvements➢ Optimized nozzle shape can maximize thrust force➢ Ø

➢ Many countries are developing space programs➢ Optimized nozzle will have minimum length & weight

Global Approach

Optimization Goals

Minimize

Flow Separation

Avoid Shock Wave

DevelopmentBack Flow

Divergent Section Length

Weight Cost

Maximize

Exit Mach Number

Exit Velocity

Thrust Force

Exit Flow Uniformity

Exit-to-Throat Area Ratio

Design Considerations• 2-D/3-D flow

• Isentropic Quasi-One dimensional

• Euler equations non-viscous flow

• Navier-Stokes equations viscous turbulent flow

• Chemical properties are not considered

• Shock wave location

• Compressible flow

• Nozzle selection (feasibility)

thttp://www.jacobsrocketry.com/general/graphics/de_leval.JPG

Design Alternative 1: Conical

• Simple Design (feasibility)

• Manufacturing

• Simulation

• Optimization

• Constant half angle at divergent section

• Velocity components in flow

http://www.tecaeromex.com/imagenes/tobera3.jpg

http://www.braeunig.us/space/pics/fig1-04.gif

Design Alternative 2: Bell

• Most commonly used design

• Parabolic cone shape

• Half angle constantly changes

• Shorter length

• Efficient at design exit pressure

http://cs.astrium.eads.net/sp/launcher-propulsion/manufacturing/images/ht-vulcain.jpg bell nozzle

http://www.braeunig.us/space/pics/fig1-05.gif

Design Alternative 3: Dual Bell

• Most difficult design of the three

• Altitude compensation (Ambient Pressure)

• Higher pressure: Wall inflection separates flow

• Lower pressure: Flow through entire geometry

• Higher overall efficiency for changes in pressure

• Lower efficiency at optimal pressurehttp://www.kspc.jaxa.jp/japanese/image/reserch/fun_03.jpg

Software Modules Involved

Geometric Shape & Grid

CFD AnalysisResponse Surface &

Optimization

Modeling

● SolidWorks/ANSYS

○ Initial Designs (from previous

work/designs)

○ Final Design (from optimization)

CFD Analysis

● LOCI

○ 2-D/3-D flow analysis

○ Hot flow/cold flow

http://flowsquare.com/wp-content/uploads/2013/12/Laval_Mach_04k.png

Optimization Process

● ModeFrontier

○ Optimization of nozzle parameters

● Response Surface

● Evolutionary Based Algorithm

○ Particle Swarm (PS)

● Optimal Solution

Manufacturing

• Dimensional Analysis (small scale)• True scale versus model

• Plexiglas design

• Alternative Materials being considered

Relevant Standards

• AS 9100 Quality management of aerospace industry• Created by SAE

– Society of Automotive Engineers

• ASME Y14.5

• Many standards are proprietary

http://spaceflight.nasa.gov/gallery/images/station/crew-10/html/jsc2004e45198.html

Validation

• Cold flow testing to be conducted with a compressed air cylinder

• Measuring devices:• Thermocouples• Pressure gauge

http://www.harborfreight.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/i/m/image_23181.jpg

Project Timeline & Responsibilities

Summary: 8 Month Capstone Project Develop a system for better performing supersonic nozzles

Maximizing

• Mach Number & Flow Uniformity Minimizing

• Divergent Length & Flow Separation

Use of different software programs Analysis & Optimization

Manufacturing & Testing Standards Cold gas