# Subsonic wind tunnel with animation

23 May 2021
1 sur 42

### Subsonic wind tunnel with animation

• 1. Design and Analysis of Subsonic Wind Tunnel and Prototype Generation Abc name Roll no.123 Def name Roll no.456 Ghi name Roll no.789 Mentor: JKL name
• 2. Abstract: • This is a study of very small-scale open-loop wind tunnel design and involves tests related to it. It will be helpful to explain aerospace engineering fundamentals to pre- college students • The designed wind tunnel will be composed by a settling chamber, a contraction section, a test section, a diffuser as well as a fan. • We will be measuring flow-field and drag force. Turbulence intensity at different cross-sections of test chamber will be determined. • A preliminary test will be on a 3d printed basic shapes and airfoil. • The result should prove to be compatible with the practical aerodynamic properties of the body and also follow the same results as some scientific literature. Thus, the wind tunnel results may be used to calibrate and verify computational fluid dynamics mathematical models.
• 3. Content: • Introduction • Problem statement • Aim and objectives • Classification of Wind Tunnel • Components of Wind Tunnel • Manufacturing Procedure • Software and Hardware Used • Testing of flow over Airfoil and Other Shapes • Calculations and Comparison • Scaling • Time plan • Cost • Limitations and challenges • Future Work
• 4. Working On: 1. Wind Tunnel Creation 2. Velocity Profile Generation 3. Lift and Drag coefficient calculation on different bodies 4. Tell at which angle airfoil create the greatest lift
• 5. Introduction: The wind tunnel is an aerodynamic device used to test and analyze the behavior, movement and flow of air around any engineering object to facilitate its design process more smoothly and more comprehensively.
• 6. Problem Statement: • To provide an alternative working environment for simulations and get the same results. • To study aerodynamics in a very practical way .
• 7. Aim and Objectives: Aim: • Design and manufacture a subsonic wind tunnel to be as a project. • It helps to do experiments and researches on a small scale and get reliable results such as lift and drag forces. Objectives: • Studying the characteristics of flow in the tunnel. • Studying the effect of winds in different structures. • Comparing CFD results to the experimental data from the prototyped wind tunnel .
• 8. Classification of Wind Tunnel:  According to the Velocity 1. Subsonic wind tunnel 2. Supersonic wind tunnel 3. Hypersonic wind tunnel 4. Transonic wind tunnel  According to the Shape 1. Open circuit wind tunnel 2. Closed circuit wind tunnel
• 9. Open Circuit Wind Tunnel • Air is drawn in from the laboratory environment, passes through the test section and is returned back to the lab through the tunnel exhaust. Fig1. Open circuit wind tunnel
• 10. Closed Circuit Wind Tunnel • Air is conducted from the exit of the test section back to the fan by a series of turning vanes. • Same air recirculated inside the wind tunnel. Fig.2 Closed Circuit wind Tunnel
• 11. Subsonic Wind Tunnel • Low-speed wind tunnels are used for operations at very low Mach Number (up to M=0.4) with speeds in the test section up to 480 km/h (~ 134 m/s ,M= 0.4) • Open Circuit and Closed circuit wind tunnels comes in its type Fig.3 Open circuit wind tunnel Fig.4 Closed circuit wind tunnel
• 12. Supersonic Wind Tunnel • High speed wind tunnels are used for operations at Mach Number (0.2<M<5) • Nozzle geometry determines Mach number and Reynold number values • Needs a drying or a pre- heating facilities • A large power demand, so mostly designed for intermittent instead of continuous operation. Fig.5 Supersonic Wind Tunnel
• 13. Hypersonic Wind Tunnel • High speed wind tunnels are used for operations at Mach Number (5<M<15) Fig.6 Hypersonic Wind Tunnel
• 14. Transonic Wind Tunnel • Wind tunnels are used for operations at Mach Number (0.3<M<1.3) Fig.7 Transonic Wind Tunnel Fig. 8 Transonic Wind Tunnel
• 15. Components of Wind Tunnel: 1. Settling Camber 2. Contraction Cone 3. Test Section 4. Diffuser 5. Drive Section Four main components of open circuit wind tunnel: Fig.9 Subsonic Wind Tunnel
• 16. CAD model of Wind Tunnel : Fig.10a CAD Model of Subsonic Wind Tunnel using FUSION 360
• 17. CAD model of Wind Tunnel : Fig.10b CAD Model of Subsonic Wind Tunnel using FUSION 360
• 18. Settling Chamber: The Settling Chamber is at the very front of the wind tunnel, and is made up of screens and honeycomb-shaped mesh, which straighten out the air and reduce turbulence Description Values Material MDF board Inlet area 42’’ * 42’’ Outlet area 42’’*42’’ Contraction ratio 1:1 Contraction angle 0 Length 6’’ Fig.11 Settling Chamber
• 19. Contraction Cone: The Contraction Cone forces a large volume of air through a small opening in order to increase the wind velocity in the tunnel Fig.12 Contraction Cone Description Values Input area of cross-section 42’’*42’’ Output area of cross-section 12’’*12’’ Contraction ratio 12.25 Length 42’’
• 20. Test Section: Test Section is the place where a model is mounted on sensors Fig.13 Test Section Description Values Material used MDF Board Length 24’’ Input area of cross-section 12’’*12’’ Output area of cross-section 12’’*12’’
• 21. Diffuser : The Diffuser is mounted at the end of the Test Section, and keeps the air running smoothly as it goes toward the back. It also increases in volume in order to slow the air down as it exits the tunnel. Fig.14 Diffuser Description Values Input area of cross-section 12’’*12’’ Output area of cross-section 22’’*22’’ Diffuser ratio 3.36 Diffuser length 63’’ Expansion angle 4.54 °
• 22. Drive Section: The Drive Section is at the very back of the wind tunnel and it is where the fan is housed. It will draw air into the wind tunnel by blowing air out of it Fig.15 Drive Section FAN Description Values Input area of cross-section 22’’*22’’ Output area of cross-section 22’’*22’’ Length 6’’ Material Used MDF Board
• 23. Manufacturing Procedure: Design and Calculations of wind tunnel parts Design of airfoil and use CFD Selection of materials Fabrication of parts Assembly of parts Testing of airfoil with air as medium Profile view on airfoil with smoke as medium Reading and calculations
• 24. Software and Hardware Used: Software: Hardware : • Mdf board • Exhaust Fan • Fog Machine • Load Cell • 3D Printed parts • Fusion 360 • ANSYS 2019 R2
• 25. Software and Hardware Used: Fig.1 Mdf board Fig.2 Exhaust fan Fig.3 Fog machine Fig.4 Load cell Fig.5 3D printed airfoil
• 26. Basic information about Airfoils: • An airfoil is the cross-sectional shape of a wing or blade. An airfoil-shaped body moving through a fluid produces an aerodynamic force. • The component of this force perpendicular to the direction of motion is called lift. • The component parallel to the direction of motion is called drag. Fig.16 Aeroplane Fig.17 Flow over airfoil
• 27. Types and Terminologies of Airfoils: Types: 1. Symmetrical airfoil: Chord line and camber line coincides. 2. Unsymmetrical airfoil: Chord line and camber line do not coincides. Terminologies: 1. Angle of attack(AOA)- The angle measured between the resultant relative wind and chord line. 2. Chord line—a straight line intersecting leading and trailing edges of the airfoil 3. Mean camber line—a line drawn halfway between the upper and lower surfaces of the airfoil. 4. Thickness: It is measured perpendicular to the camber line. Fig.18 Symmetrical and Unsymmetrical airfoil Fig.19 Terminologies of airfoil Unsymmetrical Symmetrical
• 28. Airfoil used for Project: Airfoil used: NACA0012 Description of NACA0012 Values Type Symmetrical Maximum camber 0% at 0% chord Maximum thickness 12% at 30% chord Fig.20 Airfoil NACA0012 in Airfoiltools Fig.21 Airfoil NACA0012 in Design modular
• 29. Calculations and Comparison: Reynolds number calculations: The Reynolds number is a dimensionless value that measures the ratio of inertial forces to viscous forces and describes the degree of laminar or turbulent flow. Systems that operate at the same Reynolds number will have the same flow characteristics even if the fluid, speed and characteristic lengths vary.
• 30. Animation of rotating airfoil: Giving conditions: Air velocity= 10m/s Angle of rotation=360degrees
• 31. Hand written Calculations and Formulas: Fig.38 Components of Velocity vector of air striking on Airfoil Fig.39 Components of Drag and lift forces
• 32. Hand written Calculation and Formulas:
• 36. Prototype Created: Fig.40 Settling Chamber with Contraction Cone attached Fig.41 Test section
• 37. Prototype Created: Fig.42 Assembly 1 Fig.43 Assembly 2
• 38. Cost: Sr No. Product Description Cost (INR) 1 MDF Board 2500 2 Load Cells * 2 (5kg each) 600 3 3D Printed Parts 500 4 Straws 300 5 Fan 1000 6 Mountings 200 7 Arduino UNO 500 TOTAL COST 5600
• 39. Limitations and Challenges: • Wind Tunnel Covers large area • Errors in the sensors readings • Actual results do not match with simulation results • The results of the simulation programs are inaccurate because they depend on Density and accuracy of mesh and Computer efficiency , CPU time and mesh type • Corona virus
• 40. Future Work: • Ability to control and monitor remotely using the Internet . • Use of sheet metal • Control the fan speed to obtain results at different values of air speed. • Use AC Fan for give a high speeds and PLC and VFD to better control . • Use more accurate and effective measuring tools.
• 41. References: • https://flight.engr.ucdavis.edu/facilities/aeronautical-wind-tunnel/ • https://www.sciencebuddies.org/science-fair-projects/references/how-to-build-a-wind- tunnel#testing/ • http://www.airfoiltools.com/airfoil/details?airfoil=naca0012h-sa#polars/ • https://www.grc.nasa.gov/WWW/K-12/WindTunnel/wandering_windtunnel.html