When it comes to spacecraft and aircraft research, the Transonic Wind Tunnel (DNWTWG) operated by the German Aerospace Centre (DLR) in Gttingen is the facility of choice. The TWG is used to simulate aircraft and spacecraft behaviour at speeds close to the sound barrier, in other words at around 1000 kilometres per hour and beyond. The facility in Göttingen is the most important in Germany for this type of high speed testing. The 50 metre long, 12 metre high wind tunnel is valued at €45 million.
A compressor with an output of up to twelve megawatts forces air past scale models over a test section measuring 1x1x4,5 metres. This air flow is visualised and measured. Siemens technology is used to adjust the horizontal walls as required and switch between different configurations.
The control and drive technology as well as the adaptive test section of the wind tunnel recently required modernisation. The challenge was to concentrate the automation solution, previously distributed over several controllers, into a single new controller in order to save cross-communication. The centre was also keen to install new drive technology in order to provide optimum adjustability of the horizontal walls of the adaptive test section (42 positioning axes). The aim was to eliminate the need for the distributed control boxes along the test section to gain space for the measurement technology and also the motor wiring (power, transmitter, brake). Another aim was to speed up the resetting time, maintaining the high-level main control and Simatic WinCC visualisation and adapting the interfaces of the new plant sections to them.
The company PS Control Purkott + Stamm GmbH from Niestetal in Hessen took up the challenge of this complex retrofit project, successfully overcoming all the hurdles with the benefit of its Siemens background and using Siemens technology. The ideal candidate to fulfil the various requirements was the new distributed drive variant Sinamics S120M, a compact ready-to-connect drive unit comprising a Simotics S-1FK7 servo motor with absolute encoder and directly mounted integrated power unit. It was possible to mount this directly in the test section. The link to the Sinamics assembly in the central control cabinet is formed by four AM600 adapter modules and eight CU320-2 PN control units, all of which were housed in a handy control panel measuring just 800 millimetres in width. Up to 12 Sinamics S120M units can be connected using pre-assembled plug-in hybrid cables. The hybrid cables are used to transport supply and auxiliary voltage as well as the DriveCliq signal to the servos. With an axial height of 48 and a nominal output of 570 Watts, the devices have two interfaces each for looping through from one drive to the next. This saves effort, space, time and also cable.
Only a third of the former number of connectors and a good two thirds less cabling are now required. An added benefit is improved accessibility and diagnostic capability. A new Simatic S7-1500 controller coordinates the functions of what used to be five separate controllers. “We made a conscious decision to opt for support by the specialists from Siemens, and we requested and received its valuable expertise from the design stage right through to commissioning,” says Ingo Stamm, CEO of PS Control.
The Transonic Wind Tunnel Göttingen is a closed-circuit, continuous wind tunnel for subsonic, transonic and supersonic speeds. It allows the measurement of forces, pressures, speeds and flow data. The DNW-TWG wind tunnel is used to simulate how aircraft behave in the so-called transonic domain, close to the speed of sound at around 1000 kilometres per hour – and beyond at up to 2,2 Mach, in other words at twice the speed of sound.
With a length of 50 metres and a height of 12 metres, the wind tunnel is used to research the aeroacoustic and aerodynamic characteristics of future aircraft and spacecraft.
For more information contact Jennifer Naidoo, Siemens Southern Africa, +27 (0)11 652 2795, [email protected], www.siemens.co.za
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