In the industry multiphase flows occur, for instance, in chemical reactors, power plants and turbo machinery. At the Forschungszentrum Dresden-Rossendorf a new sensor was recently developed which enables for the first time measurement and visualization of complex flows of arbitrary substance mixtures with high spatial and temporal resolution.
The analysis and modeling of industrial processes with methods of the experimental and theoretical thermal fluid dynamics is one of the tasks of the Institute of Safety Research at the Forschungszentrum Dresden-Rossendorf (FZD). Within the context of this work the new capacitance wire-mesh sensor was developed. This new sensor is a successor of the well known conductivity wire-mesh sensor, which was also developed at FZD and is currently being employed around the world. The conductivity wire mesh-sensor is based on the measurement of electrical conductivity in a flow cross-section and therefore only suited for the investigation of flow mixtures with an electrically conductive component, for example water-steam flows. The new capacitance wire-mesh sensor is now able to measure arbitrary substances, such as oil or other organic fluids. In this way, this sensor is applicable in a number of new fields, for example in process engineering and oil industry.
As the conductivity wire-mesh sensor the capacitance wire-mesh sensor consists of a set of wire electrodes stretched across a vessel or pipe in two slightly separated planes. Within one plane electrodes run in parallel whereas electrodes of different planes are perpendicular to each other. Thus, a grid of electrodes is formed in the cross-section (see figure). An associated electronics measures the electrical capacitance in all crossing points, which in turn is a measure of the dielectric constant of the substance surrounding each crossing point (the dielectric constant represents the extent to which a material concentrates the electrical field). The electronics is optimized to measure the tiny electrical capacitances of the crossing points which are in the range of only few Femtofarad (10-15 F).This can be done at very high time resolution of up to 10000 frames per second. Since different substances have different dielectric constant values, the sensor can discriminate phases or components. As an example the figure below shows a slug flow of air with a dielectric constant of 1 and silicone oil with a value of 2.7 in a pipe. Although the dielectric constants values of the two substances are rather close to each other, they are precisely distinguished by the capacitance wire-mesh sensor.
The capacitance wire-mesh sensor from the Forschungszentrum Dresden-Rossendorf may be employed in industrial applications where complex flow conditions are to be investigated. It does not require optical access to the flow as other measurement techniques do. The results of this work were recently published in the journal “Measurement Science and Technology”.
New test procedure for developing quick-charging lithium-ion batteries
07.12.2017 | Forschungszentrum Jülich
Plug & Play Light Solution for NOx measurement
01.12.2017 | Heraeus Noblelight GmbH
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...
An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications
Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...
Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.
The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...
Transistors based on carbon nanostructures: what sounds like a futuristic dream could be reality in just a few years' time. An international research team working with Empa has now succeeded in producing nanotransistors from graphene ribbons that are only a few atoms wide, as reported in the current issue of the trade journal "Nature Communications."
Graphene ribbons that are only a few atoms wide, so-called graphene nanoribbons, have special electrical properties that make them promising candidates for the...
08.12.2017 | Event News
07.12.2017 | Event News
05.12.2017 | Event News
08.12.2017 | Life Sciences
08.12.2017 | Information Technology
08.12.2017 | Information Technology