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Design and realization of micro structured surfaces for thermodynamic applications

: Schubert, A.; Hackert-Oschätzchen, M.; Meichsner, G.; Zinecker, M.


Microsystem Technologies 17 (2011), No.9, pp.1471-1479
ISSN: 0946-7076
Journal Article
Fraunhofer IWU ()
Mikrostrukturierung; Oberfläche; Oberflächeneigenschaft; Wärmeübertragung; Leistungssteigerung; Mikrokanal; Systementwurf; Laserbearbeitung; Kupfer

In the present work different micro structures with high potential for convection and nucleate boiling processes were presented. Based on literature appropriate micro structures were selected which should offer the possibility to enhance the heat transfer capability. By help of thermodynamic simulations it could be demonstrated that the convective heat transfer can be improved by use of micro structured surfaces. Especially calottes, micro channels and micro columns were determined. Primarily, the surface enlargement has the determining influence on the heat transfer efficiency. However, the design of the geometries and the arrangement of the structures also effect the heat transfer. Especially for forced convection processes the influence of these parameters has to be examined in further investigations. By use of electrochemical and laser beam machining the selected structures were manufactured in copper work pieces. With Jet-ECM realized micro structures offer a high exactness with excellent surface qualities. The high potential of Jet-ECM for a reproducible fabrication of micro structures for thermodynamic applications is obvious. Laser machined micro structures are distinguished by rough surfaces which can offer an additional positive effect on the heat transfer phenomena. So laser beam machining is also suitable for the reproducible machining of thermodynamically appropriate micro structures.