Hot film and hot wire measurement technology

In the production of a hot-film sensor array, an approx. 300 nm thin structured nickel layer and copper conductor tracks are applied to a 50 µm thick polyimide carrier foil. The process makes it possible to place more than one hundred sensors in any arrangement on the carrier foil. The foils can then be used, for example, in wind tunnel investigations to characterize the boundary layer, even on curved surfaces such as blade or aerofoil profiles.
Contact: Raphael Lorenz, M.Sc.
 

Another development at the institute is hot-wire arrays. In this new concept based on a carrier board with soldered holding needles, individual sensors are arranged one above the other. The hot wires made of platinum-coated tungsten wire are connected to the holding needles using a micro-welding device also developed at the ITFD. This system makes it possible to carry out simultaneous measurements of the velocity and turbulence profiles within the boundary layer.
Contact: Benjamin Sowa, M.Sc.

To operate the sensor arrays in a constant temperature measurement process (CTA), an electronic circuit with a measuring bridge, amplifier and filter was developed to enable simultaneous operation of the sensors. Modular 19" housings accommodate 32 channels each. The CTA measuring system thus allows a large number of measuring channels to be implemented cost-effectively and is therefore ideally suited for hot-film or hot-wire sensor arrays.
Contact: Prof. Dr.-Ing. Matthias Stripf