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Hyperloop

Rohan Deshmukh

Walter Malchodi

Rachel Warwick

5/2/16

AE 4802: Computer Aided Design Project Final Review

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What is Hyperloop?

•New paradigm of transportation as proposed by Elon Musk in his whitepaper Hyperloop Alpha

(5th mode of transportation)

•Utilizes a de-pressurized tube and novel levitation system for high-speed transport

–E.g. Air bearings & magnetic levitation

•Objective: "Design and prototype an innovative solution to the world's growing hub-to-hub

transportation needs in a cost-effective manner"

•Improve aerodynamic performance of pod

•Improve levitation performance of pod

•Ensure structural integrity of pod under

aerodynamic and static loads

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Why Hyperloop?

•Low pressure tube allows for lower ambient pressure as well as lower ambient density

–Results are reductions in drag & improvements in aerodynamic performance

𝐷 =1

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𝑃

𝑅𝑇𝑉2𝐶𝐷

•Pod levitation potentially leads to reductions in friction -> Leads to increases in speed

–Levitation height inversely proportional to cushion pressure

•Concept is like a train in passenger size, but enables the speed of an airplane

•Reduces terminal time versus aircraft, increasing versatility, and enabling short & long distance high

speed transport

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Mission Profile

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Comparison with Existing Designs: Elon's Concept

•Overview

–6834 lb pod

–Height 3.61 ft, width 4.43 ft

–Max speed of 760 mph (Mach 1)

•Air bearing levitation

–Array of 28 external pressure air bearing skis

–Provides 0.01 – 0.05 in air cushion

–0.4 lb/s @ 1.4 psi, generate 31 lbf drag

•Aerodynamics

–D= 72 lbf, P = 0.01 psia

•Propulsion

–Compressor ratio of 20:1, axial compressor

–Compressor powered by 436 hp electric motor

Pod Subsystem Layout and Conceptual Design Sketch

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Comparison with Existing Designs: MIT's Design

(Magnetic)

• Overview:

– 551 lb pod

– Max speed of 246 mph, Max acceleration of 2.4 G

• Passive Magnetic Levitation– Two arrays of 20 neodymium magnets

– 0.59 in levitation gap height

• Aerodynamics– Peak L/D = 14

– D = 0.45 lbf, P = 0.02 psia

• Pod Shell– Woven carbon fiber and polycarbonate sheets

MIT Hyperloop Team

Pod Design Cut-Away

Pod Magnetic Levitation Subsystem 6

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Comparison with Existing Designs: Purdue

Hyperloop (Air Bearing)

•Overview:–551 lb, 120" length, 38" height, 36" width

–Max speed of 224 mph, max

acceleration of 2.4 G

•Air Bearing levitation–Pressurized tank supply

–Provides 0.039 in air cushion -> 0.9 lb/s

•Aerodynamics–Analyzed in ANSYS Fluent

–CL = 0.262

–CD = 0.518

•Pod Shell–Bi-directional, double ply carbon fiber

Pod Multiview

Air Bearing Design ANSYS Fluent Velocity Profile

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Common Design Practices

• Hyperloop concept has yet to be flight proven

Current designs are in R&D phase

• Current companies have no standardized process. However, we can infer the

process based on similar vehicles and existing designs

Aircraft: the payload and dimensions are used as starting point, from which

weight would be predicted based on previous vehicles

• We started with payload, and iterated based on predicted component weights

• Aerodynamics was treated as secondary due to the short track distance and

low air density

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Surface Design Parameters: Fuselage

–Fuselage

•Height = 36-48 in

–Allow an individual to sit comfortably

within the pod

•Width = 36-48 in

–Axially symmetric design

–Allow the fuselage to fit within the

Hyperloop tube

•Length = 200-240 in

–Fits all of our components within the

shell

–Comfortably fit 2 people

–Allow for aerodynamic shaping

•Performance function of Length-to-

Diameter Ratio (L/D)

Image Credit: Drexel University Hyperloop Team

𝐶𝐷𝑜𝑓,𝑡=

0.455

log10𝜌𝑉𝐿𝜇

2.58 1 +60

𝐿 𝐷3 + 0.0025

𝐿

𝐷1 − 0.08𝑀1.45

Length

Diameter

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Surface Design Parameters: Air Bearing

•Six air bearings will provide lift, in a different manner from a traditional wing. The lift they create is a

function of their average pressure difference with the operating environment and the total area that

they cover

•Air Cushion height: 0.04 – 0.1 inches; allows for track roughness, minimize compressor power

10-18 in

(Length) 10-13 in

(Width)

2-3 in (height)

𝑃𝑐ℎ = 𝜌𝑎𝑣𝑗2𝑡(1 + cos 𝜃)

t - 1.00”; h - 0.05”; Pc – 2.7 psi

• Thrusting characteristics of a jet

fed air cushion

– Pc - pressure of the cushion

– h - levitation clearance

– ρa - air density in the tube

– vj - jet velocity

– t - jet width

– θ - jet angle relative to

horizontal𝐿 = 𝑊 = 𝑃𝑐𝑆𝑐

Image Credit: A. Bliault and L. Yun, Theory and Design of Air Cushion Craft

𝑄 = 𝑉𝑗𝑡𝐿𝑗

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Expected Flight Performance Parameters

•Speed Envelope–Cruise Speed: 200 mph

•Ceiling – ground level; however, the tube operating pressure varies–Operating Pressure: 0.02 to 14.7 psia

–Operating Temperature: 70°F

•G-loading –Horizontal: ± 2.4G

•Comes from the SpaceX pusher pod acceleration

–Vertical: ± 0.5G

•U.S. Department of Transportation requirement: ± 0.02G

–Side: ± 0.5G

•California high speed train requirement: ± 0.1G

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Hyperloop Tube & Track - Overview

Hyperloop Tube

•Structural

–Material: ASTM A1018 Grade 36 (Steel)

–Cross-Section: 72” (outer), 70.6” (inner)

–Internal Pressure: 0.02 – 14.7 psia

–No Thermal Control

•Concrete fill bed

Hyperloop Track (I-Beam)

•Structural

–Material: Aluminum 6061-T6

–Cross-Section: 5” (height), 5” (width), 0.142”

(top & bot thickness), 0.313” (mid thickness)

•Sub-track (Aluminum 6061-T61

–12” or 15” width option

All specifications given in SpaceX Hyperloop Test-Track Specification document

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Aerodynamic Performance Parameters

•𝐶𝐿 for optimal pod levitation

–Air bearing: 10+ (lift is independent of speed)

•𝑪𝑫 for optimal pod range

–Overall pod: ~0.1 to 1

•Pod operating speed

•Pod L/D ratio: 15

•Compressor/Air Bearing volumetric flow

rate (ambient): 27,000 CFM

Image Credit: Sadraey M., “Chapter 3 Drag Force and Drag Coefficient” Aircraft Performance Analysis.

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Structural Performance Parameters

•Material

–Tensile strength (Modulus of Elasticity)

–Thermal coefficient of expansion

–Strength to weight ratio

•Vibration Environment

–Nodal frequencies

–Natural frequency

–Damping ratio

•Loading Cases

–Von Mises Stress

–Deformation

–Factor of safety

•Takeoff mass : 770 lb

•Empty mass : 550 lb

–220 lb payload mass

•Aerodynamic surface material: carbon

fiber-epoxy composite

•Pod frame & Air Bearing material:

Aluminum 6061-T1

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Team Member Responsibilities

CATIA Model CFD Analysis

Part Creators

Hyperloop Tube Rohan

Aeroshell Rachel

Air Bearing Walter

Rohan• Group 1: Pre-Processing

Rachel• Group 2: Solver Setup

Walter

• Group 3: Post Processing

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Pod Aeroshell – CATIA Model and Parameters

Front View

Top View

Side View

18 ft

3.5 ft

ID Parameter Name Value or

Relation

1 Diameter 30 in

2 Rear Tip from Cylinder 50 in

3 Cylinder Length 170 in

4 Compressor Shell Length 30 in

5 Rear Tip Vertical Offset 0 in

6 Wedge Ref Pt Dist from Tip 15 in

7 Wedge Half Angle 20 deg

8 Cowling Inner Diameter 22 in

9 Ellipse half major axis 30 in

10 Ellipse to cylinder 0 in

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L/D Ratio: 5

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Pod Air Bearing – CATIA Model

2 in

10 in

45°

13.5 in

ID Parameter Name Value or Relation

1 Total Skid Area 5.6 ft2

2 Single Skid Area Total Skid Area / Number of Skids

3 Skid Width 10 in

4 Skid Length Single Skid Area / Skid Width

5 Number of Skids 6

6 Skid Lateral Offset 3 in

7 Skid Longitudinal Offset 5 in

8 Skid Height 2 in

9 Theta 45 deg

10 Material Thickness 0.3 in

11 Rib Inner Fraction 0.2

12 Rib Outer Fraction 0.95

13 Mount Fraction 0.4

14 Mount Height 1 in 17

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Pod Assembly– CATIA Model

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Air Bearings

(x6)

Aerobody

Hyperloop

Tube

I-Beam

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CFD Experiments

•Pod Analysis

–CD vs. pressure for constant speed (cruise of 200 mph)

–Only two pressures (P = 8 & 14.7 psia) was analyzed

–Compressor omitted from design for simplicity of calculations

•Initial Conditions

–V0,inlet = 200 mph

–Pexit = 8 or 14.7 psia

–Tinlet = 70°F

•Modeled as an ideal gas with coupled flow and Spalart-Allmaras turbulence19

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CFD Results: 14.7 psia

Coefficient Value

CD 0.935

CL 1.081

CL/CD 1.156

Component Value

Aerobody 0.012492

Air Bearing 0.496135

Nose 0.34

CD Total 0.85089

% Error 10%

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CFD Results: 8 psia

Coefficient Value

CD 0.603

CL 12.625

CL/CD 21

Component Value

Aerobody 0.003959

Air Bearing 0.30539

Nose 0.34

CD Total 0.649

% Error 7%

Ambient

Pressure

(psia)

CD,actual CD,theoretical

8 0.603 0.649

14.7 0.935 0.851

% Decrease 36% 24% 21

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Future CFD Work

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Min Cd

0.6

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ABAQUS FEA Mesh and Deflection

Wing Mesh

Wing Deflection

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ABAQUS FEA Von Mises Deflections

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Conclusion

•Hyperloop is a promising concept that requires further aerodynamic and structural

analysis to assess baseline conceptual designs

•Literature review provided baseline for subsystem sizing and performance analysis

–Parametric design allows for modularity in design iteration

•CFD analysis matches theoretical models governing drag

–Will require further experimentation for additional data points

•Future Work

–Additional CFD tests for assessing optimum cruise speed and lift performance

–FEA experiments analyzing G-loading, buckling, and aeroelastic coupling

–Design optimization to converge on optimum pod configuration

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Works Cited

1. A. Bliault and L. Yun, Theory and Design of Air Cushion Craft

2. California High-Speed Train Program, "Engineering Criteria" http://www.hsr.ca.gov/docs/programs/eir-

eis/statewide_techrptEngineer_rpt.pdf

3. http://hyperloop.mit.edu/

4. http://satellite.mem.drexel.edu/hyperloop/

5. http://www.purdue.edu/hyperloop/ourpod.html

6. https://steve.cd-adapco.com/articles/en_US/FAQ/JR-6-208

7. Musk, Elon. Hyperloop Alpha.

8. Space Exploration Technologies Corp. “SpaceX Hyperloop Test-Track Specification”, Revision 2.0,

November 18, 2015.

9. Space Exploration Technologies Corp. “SpaceX Hyperloop Pod Competition Rules and Requirements”,

August 20, 2015.

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Questions?