Modernization and expansion of a low-speed wind tunnel

• Subject Area: Fluid Mechanics, Technical Thermodynamics and Thermal Energy Engineering
• Term: Funded in 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 491803306

The Chair of Aerodynamics at TU Berlin applies for a modernisation and extension of its existing airfoil wind tunnel. This wind tunnel (WT) was designed and built at the beginning of the 2000’s for two-dimensional airfoil investigations with a measurement cross-section of 2.0m x 0.4m and a maximum flow velocity of 30m/s. Since 2007, the WT has been operated as an open two-dimensional cascade within SFB 557 and 1029. This WT shall now be modified and expanded to cover a broad spectrum of possible experimental configurations in future research projects. For this purpose, the test section will be enlarged to a size of 1.3m x 1.0m (HxW) at a flow velocity of approx. 35m/s. The motor, the control, and the cooling systems will be modified accordingly to accommodate the increased mass flow. At present, the engine unit is operated with two axial fans of 40.000m³/h each. These are to be replaced by two axial fans with a volume flow of 80.000m³/h each. Due to the increased volume flow, a new cooling system consisting of heat exchanger and cooling unit is required. The previous cooling unit of 15kW is to be replaced by a unit with an output of at least 40kW. Due to the enlargement of the test section, a new construction of the WT- nozzle up to and including the motor integration is necessary, though several existing parts will be re-used. Like the previous WT-parts, the new WT structural sections will be largely made of wood and mounted on metal frames. The test section will have additional optical access points to enable two- and three-dimensional flow field measurements, for example with the existing HS-PIV system. In addition, a 6-component balance, with provisions to record transient force changes as well as absolute forces and moments, will be procured. The new capability for dynamic forces and moment measurements is required, for example, in order to investigate the dynamic coupling of two wings. The sensors required for this must have a very small response threshold (mN) and a high temporal resolution. In order to enable a wide range of applications, the measuring section will be equipped with a 3-axis traverse system consisting of three drive motors, three linear traverses and a control system. This system will be used to traverse different measuring probes (five-hole probe, hot-wire, etc) and also to position or move test models in the measuring section. For the wind tunnel components such as nozzle, diffuser, deflectors, only the material is requested. The components themselves can be manufactured and assembled in the institute's own workshop.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Modernisierung und Erweiterung eines Niedergeschwindigkeitswindkanals
• Instrumentation Group: 2420 Windkanäle
• Applicant Institution: Technische Universität Berlin
• Leader: Professor Dr.-Ing. Julien Weiss