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Wind tunnel design
The document discusses the design methodology for a subsonic wind tunnel. It involves defining the test section dimensions and desired flow velocity, designing the wind tunnel components like the nozzle, diffusers, settling chamber based on the test section, calculating pressure losses throughout the components, determining overall pressure loss and flow velocity, and selecting appropriate fans to match the design. Key components are the nozzle, diffusers, settling chamber with honeycombs and screens, and corners. Design factors for these include area ratios, lengths, hydraulic diameters, porosity and Reynolds number.
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Wind tunnel design
- 1. Subsonic wind tunnel designmethodology By ANIRUDH B 11MN01
- 2. What is awind tunnel? Wind tunnels are measurement tools to study gas flows around a body and the forces generated by the gas-body interaction Mostly air is used in wind tunnels Using such tool it is possible to measure global and local flow velocities, as well as pressure and temperature around the body
- 3. Components of awind tunnel Bell mouth section/Nozzle Fine screen mesh
- 4. Components of awind tunnel Diffuser section with a Test chamber Suction fan located at The left of the diffuser
- 5. Wind tunnel Design Closed circuit wind tunnel
- 6. Wind tunnel Design TestChamber: Dimensions, shape and air velocity
- 7. Wind tunnel Design TestChamber: Dimensions, shape and air velocity *
- 8. Wind tunnel Design Nozzle:Area ratio
- 9. Wind tunnel Design Nozzle: Area ratio *
- 10. Wind tunnel Design Nozzle: Area ratio *
- 11. Wind tunnel Design Nozzle:Area ratio
- 12. Wind tunnel Design SecondDiffuser
- 13. Wind tunnel Design SecondDiffuser: Inlet cross sectional area *
- 14. Wind tunnel Design SecondDiffuser: Inlet cross sectional area *
- 15. Wind tunnel Design SecondDiffuser: Inlet cross sectional area *
- 16. Wind tunnel Design Shape adapter: Length Shape adapter is also designed and its total Length equals 0.3m
- 17. Wind tunnel Design FirstDiffuser: side l of the outlet CS area *
- 18. Wind tunnel Design FirstDiffuser: side l of the outlet CS area
- 19. Wind tunnel Design FirstDiffuser: side l of the outlet CS area *
- 20. Wind tunnel Design Corners: small corners and large corners *
- 21. Wind tunnel Design Corners:small corners and large corners *
- 22. Wind tunnel Design Settling chamber Settling chamber consists of honeycombs and mesh screen to reduce the flow turbulence before it enters the nozzle.
- 23. Wind tunnel Design Settlingchamber: honeycomb Key design factors are: 1) Length 2) Hydraulic diameter 3) porosity
- 24. Wind tunnel Design Settlingchamber: honeycomb
- 25. Wind tunnel Design Settlingchamber: honeycomb
- 26. Wind tunnel Design Settlingchamber: honeycomb
- 27. Wind tunnel Design Settlingchamber: screens To have effective reducing in turbulence the porosity must lie between 0.58 to 0.8 Different mesh qualities (coarse, medium, f ine) are efficient than single fine mesh
- 28. Wind tunnel Design Pressure losses 1) Pressure loss in constant cross section area sections (friction) 2) Pressure loss in diffusers (friction and expansion) 3) Pressure loss in corners (friction and expansion) 4)Pressure loss in screens(porosity or its complement solidity, the Reynolds number Calculated with wire diameter, and mesh factor) 5) Pressure loss in honeycombs (length to cell hydraulic diameter ratio, porosity and Reynolds number) 6) Pressure loss in nozzles (skin friction)
- 29. Wind tunnel Design Fanselection
- 30. Summary The design procedureconsists of the following main steps: 1. Defining the test section dimensions and desired flow velocity by test type; 2. Wind tunnel component design by test section criteria; 3. Wind tunnel component pressure loss calculation; 4. Determining pressure loss throughout the wind tunnel circuit as a function of the possible flow velocity in the testing section in both open and closed configurations; 5. Matching wind tunnel components to commercial fans, and energy considerations.
- 31. References: 1)Justin D Periera,“Wind tunnels-Aerodynamics, models and experiments”, Nova science publishers 2) Metha R. D., Bradshaw P. “Design Rules for Small Low Speed Wind Tunnels” Journal of Royal Aeronautical Society 1979, Vol. 73. 3)Wind tunnel design and wind tunnel parts-NASA
Editor's Notes
- #8 If the test chamber length is more than 3 times of hyddia, then the boundary layer thickness increases. If the test chamber length is less than 0.5 times of hyddia, boundary layer thickness is too short