Design Optimization of Drone Propeller

PROJECT TITLE

Design Optimization Of Drone Propeller

PROJECT NO: SDPE-AM-G8

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COURSE: WSQ SPECIALIST DIPLOMA IN PRECISION ENGINEERING (ADDITIVE MANUFACTURING)

PROJECT TITLE: _Design Optimization of Drone Propeller______

PROJECT NO: SDPE-AM-G8______

PROJECT DURATION: 10 AUG 2016 TO 19 OCT 2016

PROJECT MEMBER(S):

NAME ADMIN. NO. ELECTIVE

LAI MUN HONG 15C010U EAM506 SIM CHOO HUAT 15C021C EAM506

SUPERVISORS: Mr. SNEHARAJ MALANKAD

Proposed by:

SEG (M): [ √ ]

DATE OF SUBMISSION: 19 OCT 2016

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SUMMARY

Fig 0.0 showing mini quadcopter / drone

Surface model  Solid model  Engineering simulation with surface model  Then Engineering Simulation with solid model  3D print  Design test Fixture  Test and collect data  Compare actual with simulation result.

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ACKNOWLEDGEMENTS

Anna Flessner Engineer, Community Manager at SimScale GmbH

Sneharaj Malankad Senior Lecturer, at Nanyang Polytechnic

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TABLE OF CONTENTS

Summary 3

Acknowledgements 4

Chapter 1 Aerodynamic of Drone 6

Chapter 2 Design Consideration for Propeller 7

Chapter 3 Design and CAD Model 8-10

Chapter 4 Mesh & Simulation Setup 11-13

Chapter 5 Simulation Result 14-16

Chapter 6 Test Plan 17-18

Conclusion 19

Appendix 20

Gantt Chart 21

References 22

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CHAPTER 1

1.0 AERODYNAMIC OF DRONE

Fig 1.0 Model of quadcopter (mini drone). Moment is negated with above propeller spinning arrangement.

Propeller need to generate force called lift. Both Newton 3rd law of motion or Bernoulli’s principle can be use to explain how lift is generated.

Fig. 1.1 Fig. 1.2

Fig 1.1 Newton 3rd law, the propeller pushes a column of air downwards to create an opposite but equal trust force upwards. Fig 1.2 Bernoulli’s principle. As speed of air increases, pressure is reduced, thus creating a net force (lift) upward.

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CHAPTER 2

2.0 DESIGN CONSIDERATION FOR PROPELLER

The propeller is a spinning wing, Air moves over the surface of the airfoil generating lift. But for a quadcopter, a small motor rotates the airfoil at high speed and the propeller transform the rotory power to upward lift. Unlike an aircraft wings, the propeller is twisted.

The tip of the propeller has a higher angular velocity than the hub of the propeller. Therefore, the blade must have a lower angle of attack at the blade than at the tip (ie twist) to produce an even amount of thrust on the blade.

Therefore, propeller blades are designed twisted for stability.

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CHAPTER 3

3 DESIGN AND CAD MODEL

Software: Solidworks and OnShape Propeller Design Standard Propeller Propeller 2 (higher angle of attack)

Fig. 3.0 on the left shows standard propeller and on the right the re-design higher angle of attack propeller

CAD Model 3.0 Surface modelling

Standard Propeller

Propeller 2

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CHAPTER 3

3 DESIGN AND CAD MODEL

3.0 Surface modelling

Trio-Peller (Base on propeller 2)

Surface modelling is first used for engineering simulation to reduce computing load and also there are lesser surfaces to select for boundary conditions to speed things up.

3.1 Solid Modelling

Propeller 2

Propeller 2 (dimples)

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CHAPTER 3

3 DESIGN AND CAD MODEL

Propeller 2 (Bumps)

Propeller 2 (Humps)

Quad_peller

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CHAPTER 4

4. MESH & SIMULATION SETUP

Software: Simscale and Solidworks 4.0 Create project in Simscale 4.1 Upload CAD (step file) 4.2 Create Mesh (refer Appendix 1), fine mesh near drone due to turbulence; coarse mesh at the walls due to very little interaction with air. Type of mesh: Hex-dominant parametric (only CFD) 4.2.0 Base Mesh (coarse) for Box (Represent air volume around the drone) 4.2.1 Surface Mesh refinement for Rotation of air around propeller 4.2.2 Surface Mesh refinement for drone frame 4.2.3 Surface Mesh refinement (finest) for blades as most changes in air flow here. 4.2.4 Region refinement for Cartesian Box adjacent to drone 4.2.5 Layer refinement to resolve turbulence for drone surfaces. 4.2.6 Run and create Mesh!

Fig 4.0 Fig 4.1

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CHAPTER 4

4. MESH & SIMULATION SETUP Cut model of simulation domain; quarter of quadcopter is modelled. Symmetry is use to reduce the size of the model. Advantage is decrease size of computation model. The outer box represents the air volume around the quadcopter simulated.

Fig 4.2 Cylindrical solid to define rotation of air around the propeller

Fig 4.3 Final Mesh

4.3. Setup Simulation (refer Appendix 2) 4.3.0 Create new Simulation – type: incompressible fluid dynamics – steady state, k-omega SST 4.3.1 Choose the mesh. 4.3.2 Apply boundary conditions 4.3.2.0 Choose material – Air. Apply to volumes. 4.3.2.1 Select two faces of symmetry 4.3.2.2 Add boundary condition for 4 other ‘slip’ walls – no interaction with air 4.3.2.3 Add boundary condition for faces of the drone, ‘no slip’ wall – consider air friction. 4.3.2.4 Add rotating zone to the solid cylinder around the propellers. Set the angular velocity

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CHAPTER 4

4. MESH & SIMULATION SETUP 4.3.3 Choose the Pressure Solver ‘GAMG’ and Velocity Solver ‘Smooth Solver’, K and Omega. 4.3.4 Choose time step in iterative Simulation Control

Goal in simulation to see which design creating more lift, so in Result Control choose ‘Force and Moment’ and select all faces of the drone.

Create Simulation run for 525 rad/sec, 1050 rad/sec, 1575 rad/sec, 2100 rad/sec. Hit Start!

4.4. Post-Processor Results 4.4.0 Force plot - Pressure Force y direction is the lift in Newton (N) 4.4.1 Solution field - Visualization of velocity field around propeller

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CHAPTER 5

5. SIMULATION RESULTS

Lift force, Fy (N) vs Propeller type (rad/sec) 8.0

7.0

6.0

5.0 525 rad/sec 4.0 1050 rad/sec 1575 rad/sec 3.0 2100 rad/sec 2.0

1.0

0.0 Std Propeller Propeller 2 Propeller 2 Propeller 2 Propeller 2 Propeller 2 (Benchmark) Dimple Bump Hump Quad_peller

Fig 5.0 shows propeller with higher angle of attack and 4 blades has the most optimal airlift at all rotational speed

5.0 Analysis of results with Force Plot and solution Field 5.0.1 Force plot show redesigned propeller with high angle of attack and increase number of blades to four increase lift force without increasing the undesirable lateral forces Fx and Fy significantly. Refer Appendix 3.

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CHAPTER 5

5. SIMULATION RESULTS Lateral force, Fx(N) vs Propeller type (rad/sec) 0.00 Std Propeller Propeller 2 Propeller 2 Propeller 2 Propeller 2 Propeller 2 (Benchmark) Dimple Bump Hump Quad_peller -0.05

-0.10 525 rad/sec 1050 rad/sec -0.15 1575 rad/sec -0.20 2100 rad/sec

-0.25

-0.30

Lateral force, Fz (N) vs Propeller type (rad/sec) 0.40

0.35

0.30

0.25 525 rad/sec 0.20 1050 rad/sec 0.15 1575 rad/sec

0.10 2100 rad/sec

0.05

0.00 Std Propeller Propeller 2 Propeller 2 Propeller 2 Propeller 2 Propeller 2 (Benchmark) Dimple Bump Hump Quad_peller -0.05

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CHAPTER 5

5. SIMULATION RESULTS

Standard Propeller Higher angle of attack

Trio Propeller Quad Propeller

Fig 5.1 shows propeller with higher angle of attack and 4 blades has the maximum velocity field 5.0.1 Velocity Field shows highest air flow for Quad_peller, thus highest airlift. Refer Appendix 4.

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CHAPTER 6

6. TEST PLAN

Fig 6.0 Study of natural resonance of propeller (mat’l ABS) using Solidworks

Study name: Natural frequency of Quadra_Propeller Mode No. Frequency(Rad/sec) Frequency(Hertz) Period(Seconds) 1 1568.00 249.56 0.0040 2 1572.00 250.19 0.0040 3 1572.40 250.25 0.0040 4 1575.30 250.71 0.0040

5 4865.00 774.29 0.0013 Fig 6.1 Shows fundamental resonance occurs at about 250 Hz

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CHAPTER 6

6. TEST PLAN

Fig 6.2 Test Fixture to secure above a simple weighing machine for measurement of Propeller trust force

Resonance occurs at 250 Hz (15000 rpm / 1570 rad/sec), thus recommended max motor test speed not beyond 200 Hz (12000 rpm). Safety factor of 1.25

Fig 6.3 Propeller test run:

Click https://drive.google.com/open?id=0B-oWcpQpRgJdSWZIQkFTTHlfS0U

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CONCLUSION

UP was chosen to print the parts as ABS material is found strong enough in our simulation for testing with motor and controller up to 15000 rpm. However due to in adequate material, some of our parts are SLS printed (Nylon material). The SLS propeller passed the test run with motor and controller.

Some of the small features notably, the dimples and bumps did not turn out as well as we wanted them to be. Also, for the SLS printed Quad-drone, the Quadra-peller broke off at the 2mm Ø axle joint easily.

We learnt that Additive manufacturing is good for quick prototype and together with engineering simulation software to save design time and cost. However, care has to be taken for fine features. In our case our prototype is functional as well. We can modify to improve existing propellers on actual quadcopter / drone and replace the current parts to achieve a more effective lift force.

With CAD software, engineering simulation software and 3D printers, hobbyist and professional can toy with and exchange different ideas thus stimulating a more vibrant online community.

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APPENDIX

Appendix 1: Mesh Setup

Appendix 2: Simulation Setup

Appendix 3: Raw data and Chart

Appendix 4: Detail Results

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Project Timeline 10 Aug to 19 Oct 2016 Week Week Week Week Week Week Week Week Week Week 1 2 3 4 5 6 7 8 9 10

Gather ideas, research, discussion and planning

3D modelling in Onshape software

3D modelling of the prototype in Solidworks software

Frequency Resonance & CFD simulation

Confirm STL file in magics.

Fabrication of model in U-print

Fabrication of actual model in FDM & SLS

Post processing of part

Final Presentation

Preparation of parts/reports/CADs submission

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REFERENCES

1. Udemy, Engineering Simulation with SimScale: Drone Aerodynamics https://www.udemy.com/engineering-simulation-with-simscale-drone- aerodynamics

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