flow and structural analysis of a quadcopter

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International Journal of Advanced Research in Engineering and Technology (IJARET) Volume 11, Issue 8, August 2020, pp. 880-888, Article ID: IJARET_11_08_086 Available online at http://iaeme.com/Home/issue/IJARET?Volume=11&Issue=8 ISSN Print: 0976-6480 and ISSN Online: 0976-6499 DOI: 10.34218/IJARET.11.8.2020.086

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FLOW AND STRUCTURAL ANALYSIS OF A QUADCOPTER UAV

Faraz Ahmad Department of Mechanical Engineering, Graphic Era

Deemed to be University, Dehradun, India

Pushpendra Kumar Department of Mechanical Engineering, Graphic Era


Yasar Khan Department of Mechanical Engineering, Indian Institute of

Technology, Roorkee, India

Pravin P. Patil Department of Mechanical Engineering, Graphic Era


ABSTRACT Propellers are responsible for the altitude and attitude motions of a Quadcopter

type of unmanned aerial vehicles (UAV). A propeller generates the thrust in the axial direction of the propeller’s rotation. In the present study, the computational fluid

dynamics (CFD) analysis has been performed on a Quadcopter and its propeller to calculate the thrust generated by the propeller under the applied rotational speed. The solid CAD models of a Quadcopter and propeller have been designed in Catia v5. The created propeller design has been imported to ANSYS workbench fluid flow (fluent)

module. Simulation has been conducted by using the k-epsilon turbulence model. Furthermore, the obtained results have been imported from fluent flow module to

transient structural module in order to find out the deformation and stress induced in the propeller, due to the pressure generated by the rotation of propeller at 6500 RPM. From the obtained results, it can be seen that the designed propeller can generate the required amount of thrust force to lift the Quadcopter and can sustain the dynamic loading without failure. Keywords: Quadcopter, Propeller, CFD, Fluent, Thrust force, Pre-stress analysis.Cite this Article: Faraz Ahmad, Pushpendra Kumar, Yasar Khan and Pravin P. Patil, Flow and Structural Analysis of a Quadcopter UAV, International Journal of Advanced Research in Engineering and Technology (IJARET), 11(8), 2020, pp. 880-888 http://iaeme.com/Home/issue/IJARET?Volume=11&Issue=8

Flow and Structural Analysis of a Quadcopter UAV


1. INTRODUCTION A Quadcopter UAV is a special type of helicopter with four propellers. It can carry more

payload than conventional helicopter because of the more thrust force produced by four propellers. Add-on to this, Quadcopter has better steering control over the helicopter because,

in Quadcopter four propellers help in roll, pitch and yaw motions [1,8,10,11], whereas in helicopter only two propellers are there. The propellers are designed carefully because they produce the required thrust for the Quadcopter’s motion in three dimensional space. Quadcopter

has large range of applications in transportation, spy vision and aerial photography, which creates interest in researchers to improve maneuverability and stability of a Quadcopter. In the existing literature on CFD analysis of a Quadcopter, some contributions are described here.

Penkov et al. [2] studied the shroud influence on lift force by CFD simulation. F. Ahmad et al. [3] analyzed the Quadcopter body frame on the basis of vibration frequency. The frame was tested under two different boundary condition to find out the resonance failure frequency. M.P. Kishore et al. [4] performed the flow simulation on a marine propeller. Furthermore, velocity and pressure distribution of flow around the propeller was calculated. M Anudeep et.al [5] has designed and analyzed the quadcopter different partson the basis of static analysis to find out the optimum design. E. Kuantama et al. [6] performed the CFD analysis to find out the power

efficient propeller of suitable size. The simulation was performed for different speeds to determine the values of thrust and pressure on the propeller. The simulation results were

compared with data-sheets of three commercial rotor specifications. S. Wang et al. [7] performed the static structural and fluent flow analyses on an agricultural unmanned aerial vehicle. The main wing beam was characterized by calculating the deformation at six different points on the wing surface. F. Ahmad [9] calculated the resonance frequency of a Quadcopter propeller and find out the best suited material for heavy payload application.

The main objective of this study is to find out the value of thrust force generated by the propeller at different angular speed. Furthermore, obtained thrust force was used in finding out the value of thrust Coefficient. The present paper is arranged in following section; first section presents the Quadcopter introduction with literature; second section presents the solid CAD modeling of Quadcopter; in third section Quadcopter was analyzed by CFD and pre-stressed analysis to determine the thrust force, propeller deformation, thrust coefficient and Quadcopter lift and drag coefficient; forth section conclude the complete study.

2. CAD MODELING The Quadcopter performance is influence by the flying conditions i.e., angle of air attack, flying medium density and the Quadcopter geometry specially the propellers. It is an under actuated

system, where the motion of Quadcopter in three dimensional space is controlled by four propellers. In order to analyze a Quadcopter based on finite element method (FEM), the first

step is to develop the CAD model including different components. The CAD model of a Quadcopter has been created in Catia v5 modeling software. Figure 1 shows the developed “ ”

solid design of a Quadcopter with rotors. The Quadcopter arms have been designed aerodynamically (airfoil shape) to reduce the drag and to improve the accuracy of roll and pitch angles ( Figure 2 ).Moreover, the propeller has been designed in curved shape to increase the “ ”mechanical strength as shown in Figure 3 . “ ”

Faraz Ahmad, Pushpendra Kumar, Yasar Khan and Pravin P. Patil


Figure 1 Quadcopter Design Model

Figure 2 Aerodynamic Arm. Curve Shape Propeller.Figure 3

3. CFD ANALYSIS CFD is a numerical simulation approach which deals with the fluid or fluid-solid interaction. This approach is based on the rules of fluid mechanics to solve the engineering problems related

to fluid flow. Different simulation tools provide a user friendly interface to analyze the interaction of liquid or gas with solid. Nowadays, researchers and engineers are using CFD in solving the engineering problems such as, aerodynamics, aerospace, fluid flow, heat transfer, mass transfer, engine and combustion analysis, etc. To analyze the Quadcopter, different steps are presented in the following subsections.

3.1. Flow Analysis of the Propeller Quadcopter’s

The CAD model of the propeller has been imported to fluent flow module in Ansys. An enclosure has been created around the propeller to perform the flow simulation. Figure 4 “ ”

shows the design of propeller and enclosure with applied inlet and outlet boundary conditions. The propeller has been meshed with mesh sizing tool with maximum mesh size of 5 mm. The air velocity at inlet has been taken very less (0.1 m/s) and the propeller is rotated with 6500 rpm. The parameter used for the CFD simulation is listed in Table 1 . “ ”



Figure 4 Propeller with Enclosure. Propeller with Meshing. Figure 5

Table 1 Data Used In The Simulation.

Parameter Parameter value Propeller rotation 6500rpm

Maximum meshing size 5 mm Gravity 9.81 m/s2

Time Transient Time step size 0.15

Number of time step 26 Number of iteration per step 100

Viscous model K-Epsilon (realizable) Near wall treatment Scalable wall function

Flying medium Air Specified operating density 1.225 kg/m3

Figure 6 Simulation in Ansys for Thrust Force Calculation.

The flow simulation has been performed successfully using the K-epsilon turbulent model with 100 iterations. Figure 6 shows the value of thrust force i.e., 2.6953 N. Figure 7 shows “ ” “ ”

the pressure reading on the propeller, while “figures 8 , ” “figures 9 show the velocity streaming ”on the rotary domain surface and around the propeller, respectively. The considered Quadcopter was made up of carbon fiber reinforced polymer (CFRP) material and it has a total mass of 0.94768 kg.



Figure 7 Propeller Pressure Contours. Velocity contours. Figure 8

Figure 9 Velocity Streaming Around the Propeller. Quadcopter with Enclosure Figure 10 .

The thrust force required to fly the Quadcopter F m g = 0.94768*9.81=9.297 N

Hence, the thrust force required per propeller=4F =9.297/4=2.324 N

The simulation thrust (2.695 N) is greater than the calculated thrust (2.324 N). Hence, for the given flow conditions, the designed propeller can fly the Quadcopter at 6500 rpm.

3.2. Aerodynamic Analysis o Quadcopter f In this section the complete Quadcopter has been simulated for analyzing the aerodynamic performance. The designed CAD has been imported from Catia to Ansys workbench for the flow analysis. The virtual wind tunnel type enclosure has been created around the Quadcopter as shown in Figure 10 . “ ” “ ” “figure ”Figure 11 and 12 show the mesh model of the Quadcopter alone and with the enclosure, respectively. Figure 13 shows the direction of air from inlet to “ ”outlet. The parameters used for the CFD simulation are listed below.

Number of iterations taken for calculation is 500. Inlet velocity of air is 15 m/sec. Static pressure at outlet is 1 bar.



Figure 11 Mesh Model of Quadcopter. Figure 12 Mesh Model with Enclosure.

“ ” ” ”Figure 14 , “figure 15 and “figure 16 , “figure 17 shows the pressure and velocity streams, respectively, the calculated values are 100100 Pa and 24.29 m/s2, respectively. “Figure 18 and igure 19 , show the values of coefficient of drag and the coefficient of lift for the ” “f ”

Quadcopter, which are 0.61 and 0.06, respectively.

Figure 13 Input Output Boundary Conditions. Pressure Contours o Quadcopter. Figure 14 f

Figure 15 Pressure with Streamlines. Velocity Contours with Streamlines. Figure 16



Figure 17 Velocity Streamlines. Figure 18 Coefficient Of Drag.

Figure 19 Coefficient of Lift. Imported Pressure. Figure 20

3.3. -Stressed Analysis PreIn this section, the propeller is fixed at the center as shown in figure 21 (blue color) and the “ ”value of pressure has been imported from the fluent module to the transient structural module.

Figure 20 shows the imported pressure values. The transient structural analysis has been ”

performed with applied pressure and the fixed boundary condition. Simulation has been conducted with the same values of time step and time interval as in the propeller flow analysis.

Figure 21 Fixed Boundary Condition. Total Deformation. Figure 22

From figures 22, 23 and 24, it can be observed that the maximum values of deformation (0.0073 mm), stress (0.1926 MPa) and strain (2.76e-6) are very low. Hence, the propeller can sustain the pressure at 6500 rpm without bending or failure.



Figure 23 Equivalent Stress. Equivalent Strain. Figure 24

3.4. Calculation of thrust coefficient In this section, the thrust force is calculated at different angular speeds. The main purpose of this calculation is to find the approximate value of the thrust coefficient Kt. The relation between

the thrust force ( ) and the angular speed ( ) is given by =F ω F Kt ω2 . Hence, K t can be approximated by the CFD analysis of thrust forces at different angular speeds. In Table 2 , ten “ ”arbitrary values of angular speeds of the propeller are taken and the corresponding thrust forces are calculated using CFD. Finally, the average value of the thrust coefficient is calculated as 5.676e-6N-s2/rad2

Table 2 Thrust Force at Different Angular Speed.

S.N. Angular speed (rpm)

Angular speed (rad/s)

Thrust by CFD(N) Kt = F/ω2

(N-s 2/rad2) Average

of Kt 1. 3586 376 0.7845 5.549e-6

5.676e-6

2. 4811 504 1.4333 5.642e-6 3. 5072 531 1.6146 5.726e-6 4. 5783 606 2.0649 5.622e-6 5. 6991 732 3.1055 5.795e-6 6. 7857 823 3.9573 5.842e-6 7. 8930 935 5.0242 5.747e-6 8. 9037 946 5.033 5.623e-6 9. 10016 1049 6.185 5.620e-6 10. 11341 1188 7.9041 5.600e-6

4. CONCLUSION The CAD model of a Quadcopter has been designed in CATIA and analyzed in ANSYS. The flow analysis is performed to observe the behavior of air on the Quadcopter and its propeller. The value of thrust forces at different angular speeds has been calculated using CFD analysis in order to calculate the thrust coefficient. Following are the results which have been calculated in this study.

Thrust force generated by the propeller =2.6953 N at 6500 RPM Propeller pressure contours =5944.3 Pa (maximum). Propeller velocity contours =154.8 m/s (maximum). Quadcopter pressure contours =100100 Pa (maximum). Quadcopter velocity contours =24.29 m/s (maximum). Coefficient of lift =0.06 Coefficient of drag =0.61



Coefficient of thrust =5.676e-6

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Nonlinear Studies, 23(4). [2] Penkov, I., & Aleksandrov, D. (2017). Propeller shrouding influence on lift force of mini

unmanned quadcopter. International Journal of Automotive and Mechanical Engineering, 14, 4486-4495.

[3] Faraz Ahmad, Pushpendra Kumar, Anamika Bhandari, Pravin P. Patil & Ghosal A. (2018). Finite Element Analysis Based Material Optimization Of A Quadcopter Body Frame.

International Journal of Mechanical and Production Engineering Research and Development (IJMPERD). 8 (7), 1342-1347. ISSN (P): 2249-6890; ISSN (E).

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[9] Ahmad, F., Bhandari, A., Kumar, P., & Patil, P. P. (2019, November). Modeling and Mechanical Vibration characteristics analysis of a Quadcopter Propeller using FEA. In IOP Conference Series: Materials Science and Engineering (Vol. 577, No. 1, p. 012022). IOP Publishing.

[10] Matouk, D., Ahmad, F., Kumar, P., Merzouki, R., Singh, M., & Abdessemed, F. (2018, October). Bond Graph Model-Based Control of the Quadcopter Dynamics. In 2018 7th

International Conference on Systems and Control (ICSC) (pp. 435-440). IEEE. [11] Ahmad, F., Kumar, P., Bhandari, A., & Patil, P. P. (2020). Simulation of the Quadcopter

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flow and structural analysis of a quadcopter

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