Design Optimization Of Drone Propeller

Transcription

1 PROJECT TITLE Design Optimization Of Drone Propeller PROJECT NO: SDPE-AM-G8 1

2 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

3 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. 3

4 ACKNOWLEDGEMENTS Anna Flessner Engineer, Community Manager at SimScale GmbH Sneharaj Malankad Senior Lecturer, at Nanyang Polytechnic 4

5 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 Chapter 5 Simulation Result Chapter 6 Test Plan Conclusion 19 Appendix 20 Gantt Chart 21 References 22 5

6 CHAPTER 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 3 rd 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 3 rd 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. 6

7 CHAPTER 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. 7

8 Software: Solidworks and OnShape Propeller Design CHAPTER 3 3 DESIGN AND CAD MODEL Standard Propeller (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 8

9 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 (dimples) 9

10 CHAPTER 3 3 DESIGN AND CAD MODEL (Bumps) (Humps) Quad_peller 10

11 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) Base Mesh (coarse) for Box (Represent air volume around the drone) Surface Mesh refinement for Rotation of air around propeller Surface Mesh refinement for drone frame Surface Mesh refinement (finest) for blades as most changes in air flow here Region refinement for Cartesian Box adjacent to drone Layer refinement to resolve turbulence for drone surfaces Run and create Mesh! Fig 4.0 Fig

12 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) Create new Simulation type: incompressible fluid dynamics steady state, k-omega SST Choose the mesh Apply boundary conditions Choose material Air. Apply to volumes Select two faces of symmetry Add boundary condition for 4 other slip walls no interaction with air Add boundary condition for faces of the drone, no slip wall consider air friction Add rotating zone to the solid cylinder around the propellers. Set the angular velocity 12

13 CHAPTER 4 4. MESH & SIMULATION SETUP Choose the Pressure Solver GAMG and Velocity Solver Smooth Solver, K and Omega 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 Force plot - Pressure Force y direction is the lift in Newton (N) Solution field - Visualization of velocity field around propeller 13

14 CHAPTER 5 5. SIMULATION RESULTS 8.0 Lift force, Fy (N) vs Propeller type (rad/sec) rad/sec 1050 rad/sec 1575 rad/sec 2100 rad/sec Std Propeller (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 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. 14

15 CHAPTER Std Propeller (Benchmark) Dimple Bump 5. SIMULATION RESULTS Lateral force, Fx(N) vs Propeller type (rad/sec) Hump Quad_peller 525 rad/sec 1050 rad/sec 1575 rad/sec 2100 rad/sec Lateral force, Fz (N) vs Propeller type (rad/sec) rad/sec 1050 rad/sec 1575 rad/sec 2100 rad/sec Std Propeller (Benchmark) Dimple Bump Hump Quad_peller 15

16 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 Velocity Field shows highest air flow for Quad_peller, thus highest airlift. Refer Appendix 4. 16

17 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) Fig 6.1 Shows fundamental resonance occurs at about 250 Hz 17

18 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 18

19 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 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. 19

20 APPENDIX Appendix 1: Mesh Setup Appendix 2: Simulation Setup Appendix 3: Raw data and Chart Appendix 4: Detail Results 20

21 Project Timeline 10 Aug to 19 Oct 2016 Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 Week 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 21

22 REFERENCES 1. Udemy, Engineering Simulation with SimScale: Drone Aerodynamics 22