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Emulsion Flow Analysis of a Sensor Probe for Sustainable Machine Operation

Foundation Institute for Materials Science, 28359 Bremen, Germany
Particles and Process Engineering Department, University of Bremen, 28359 Bremen, Germany
Chemical Engineering Department, Polytechnic School of the University of São Paulo, São Paulo 05508-010, Brazil
Author to whom correspondence should be addressed.
Academic Editors: Hamid Arastoopour and Goodarz Ahmadi
Received: 8 December 2016 / Accepted: 17 February 2017 / Published: 23 February 2017
PDF [4055 KB, uploaded 24 February 2017]


Working fluids possess several applications in manufacturing processes, for instance lubricants in metals machining. Typical metal working fluids are formulated as oil-in-water emulsions. The maintenance of the physical stability of the working fluid during operation is a key factor for the sustainability of the relevant process. Therefore, continuous control of the working fluids stability and performance during machine operation is an essential tool for maintenance of the process performance. Turbidity measurement (TM) is a process technique for emulsion stability and quality assessment, where light transmission and absorption of an emulsion system is analyzed. However, for in-process measurement and fluid quality detection during the machine operation by TM, it is necessary to implement a transmission inline sensor into the working fluid flow line. The continuous flow measurement may cause problems for long-term sensor operation regarding, e.g., biofouling of the sensor optical glasses or erroneous measurements due to emulsion droplets segregation effects. In the present investigation, computational fluid dynamic (CFD) simulations have been adapted to obtain the emulsion flow conditions within a typical TM sensor probe, thereby allowing an assessment of the adhesion probability of microorganisms as well as droplet segregation effects. The simulation results indicate some temporal changes of the dispersed phase concentration in the detected emulsion flow. Due to droplet segregation in the emulsion, the flow velocity needs to exceed a certain value for reliable operation. It is shown here that in this flow regime microbiological attachments on the probe surfaces may be sufficiently avoided. A minimum critical flow velocity is derived to avoid biomolecule adhesion and thus durable operation of the sensor. View Full-Text
Keywords: multiphase flow; machining process sustainability; sensor measurement; metal working fluid analysis multiphase flow; machining process sustainability; sensor measurement; metal working fluid analysis

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Sander, S.; Glasse, B.; Grosche, L.; De Paiva, J.L.; Guardani, R.; Fritsching, U. Emulsion Flow Analysis of a Sensor Probe for Sustainable Machine Operation. Fluids 2017, 2, 9.

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