European Strategic Wind tunnels
Improved Research Potential
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DNW Large Lowspeed Facility
Description of the infrastructure:
The DNW-LLF is a closed circuit low-speed wind tunnel with a
maximum speed of M= 0.4. The tunnel has been in operation
since 1980. The LLF has two interchangeable test sections of
9.5x9.5 and 6x8m, respectively, with which four test section
configurations including one open jet can be realised. The
air in the tunnel is propelled by a single stage fan driven
by an internal electric drive with a power output of 12.65
MW. The tunnel is provided with a heat exchanger-honeycomb
flow rectifier and 4 anti-turbulence screens in the settling
chamber. The LLF has an external balance and an internal
balance sting system for model support and is further
equipped with a Moving Belt Ground Plane (MBGP) with a
maximum speed of 40 m/s. The MBGP is provided with a
boundary layer removal system that scoops and re-injects the
floor boundary layer air into the tunnel. From the start the
tunnel has been designed for aeroacoustic research testing
in combination with take-off and landing studies of aircraft
and helicopter models or full-size components. The upgrade
of LLF in the framework of ESWIRP foresees in major
improvements on the existing MBGP.
The improprements will support:
- The flatness of the belt under expected future heavy upward and downward aerodynamic loads.
- The prevention of hot areas on the belt due to friction with the belt bed.
- Less wear of the belt and therefore a longer lifetime of the belt.
- Improved tracking of the belt under asymmetrical aerodynamic loads.
The realization of these improvements will give a better simulation of the relative motion between an aircraft and the runway, especially for future new engine concepts. The reliability of the MGBP system will improve and consequently a considerable increase in productivity can be offered to the aeronautics research community.