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Measurements of 3-D Velocity Fields in Microgeometries
2002 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

This work describes a method for determining a three-dimensional velocity profile of a flow through a micro geometry. The aim of this thesis is to further develop a micro-PIV method previously used to measure displacements and deformations in a plane. Micro-PIV methods are not a in it self a new method in this sorts of applications, on the contrary, it is a well known and documented method for measuring and calculating velocities and deformations in micro scales. The recent progress in micro-technology pushes the development of measuring techniques adapted for micro-geometries forward. The method that is developed in this thesis is not interesting entirely for scientists but also for companies in areas such as wood fiber products, polymer composites, micro fluidics and biomaterial. The unique in this method is to show that the technique can be used to measure a tree- dimensional velocity profile. The method that this work is based on has been developed at Luleå University of Technology. The earlier method is based on correlation calculation between images that has been taken with a CCD-camera, parted with a time interval. The achieving goal with PIV-methods is to compare the intensity between these images, and in that way find the displacements on the specimen. The development in this thesis is to gather data from layers through a capillary tube. The gathered information is then put together, and this gives a picture of the flow through the geometry in a three-dimensional perspective. The head alignment in this work has been to find a qualitative picture of the three-dimensional velocity profile. The trail setup does not allow any quantitative validation of the velocities. Therefore has the concentration in the work been to find a method with potential for future development, that measures the shape of the velocity profile in a truthfully way. The method that has been developed in this work and that is built on the earlier PIV-method is developed in the mathematic program Matlab. This program is suitable for the calculations and visualizations that are required. A future step in development of this method is to rewrite the Matlab codes in C-code for increased speed in the calculations. The future development of the technique that is presented in this thesis should include measurements in more complicated geometries such as constrictions or bent capillary tubes. Future development could also include transient flows or real time measurements of micro flows. The measurements that has been done in this work has been done on Newtonian flows, where the measured velocities easily can be verified against known theories. An area that this method can be used in the future is flow measurements on non- Newtonian fluids. The velocity profiles of the non-Newtonian fluids can be difficult to calculate since the physics behind them can be complex. Therefore can one see a bright future of this method since it can determine the shape of the velocity profiles of non-Newtonian fluids in an experimental way.

Place, publisher, year, edition, pages
Keyword [en]
Technology, micro-PIV method, measuring techniques
Keyword [sv]
URN: urn:nbn:se:ltu:diva-54520ISRN: LTU-EX--02/301--SELocal ID: b77d6d43-af7c-4ecf-b819-d48ce8f81b98OAI: diva2:1027902
Subject / course
Student thesis, at least 30 credits
Educational program
Engineering Physics, master's level
Validerat; 20101217 (root)Available from: 2016-10-04 Created: 2016-10-04Bibliographically approved

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