On board a ship, as in many other areas, there are numerous pipelines and hose connections to transport liquids. The energy required for their transport is largely determined by the inner sides of the pipes, since the flow is impaired here by friction losses and turbulence. In AIRTUBE, the experience gained in the AIRCOAT project with technical films for friction reduction is to be further developed and tested for use in this area. This will involve the use of a plastic foil that mimics the biomimetic properties of the Salvinia plant and achieves friction reduction with the formation of a layer of air on the surface.
The AIRTUBE project aims to develop and describe a demonstrator for water pipes with an air-retaining inner coating, thus proving the technical feasibility of the idea. In doing so, the project partners will investigate suitable manufacturing technologies for the internal pipe coating and experiment with the influence of different geometries of pipe cross sections on friction losses and turbulence. In addition, a numerical validation of the friction properties and a proof of concept will be performed.
Role of the CML in AIRTUBE:
At the CML, measurements of the flows in a tube are performed non-invasively in AIRTUBE, i.e. by means of Laser Doppler Velocemitry. When using this measuring method, the flow in the tube is not disturbed by measuring sensors and the determination of flow profiles as well as high-resolution measurements close to the wall are possible. A demonstrator is also built at the CML which can be used to show the reduced pipe friction after coating. Thus, the CML contributes significantly to the validation and demonstration of the solutions, because the results of the measurements in the flow channel have a direct influence on further development of the plastic foil, the design of the demonstrator and the evaluation of influences of different pipe geometries.
Fraunhofer Center for Maritime Logistics and Services CML, Germany (project lead); Karlsruhe Institute of Technology, Germany; Bremen University of Applied Sciences, Biometrics-Innocation-Centre, Germany.
AIRTUBE is funded by the BMBF in the period December 2021 - November 2022.