Performance evaluation of the flow in micro junctions : head change versus head loss coefficients

Publikationstyp
Conference Paper
Date Issued
2013
Sprache
English
Author(s)
Schmandt, Bastian  
Herwig, Heinz  
Institut
Technische Thermodynamik M-21  
Thermofluiddynamik (M-21H)  
TORE-URI
http://hdl.handle.net/11420/6044
Article Number
ICNMM2013-73031, V001T02A001
Citation
Proceedings of the ASME 11th International Conference on Nanochannels, Microchannels, and Minichannels - 2013 : single phase gas flow ... / presented at ASME 2013 11th International Conference on Nanochannels, Microchannels and Minichannels ; June 16 - 19, 2013 Sapporo, Japan / sponsored by ASME. - New York, NY : ASME, 2013. - Paper no. ICNMM2013-73031, V001T02A001; 8 pages
Contribution to Conference
ASME 2013 11th International Conference on Nanochannels, Microchannels and Minichannels, ICNMM 2013  
Publisher DOI
10.1115/ICNMM2013-73031
Scopus ID
2-s2.0-84892654847
Publisher
ASME
Losses due to the flow through conduit components in a pipe system can be characterised by head loss coefficients. They basically account for the dissipation in the flow field or, in a more general sense, for the entropy generation due to the conduit component under consideration. When only one single mass flow rate is involved, an entropy based approach is straight forward and m can be used as a general reference quantity. If, however, the mass flow rate is split or united like in junctions, some new aspects appear. In our study the general approach for these kind of conduit components is discussed. Like for single mass flow rates losses are accounted for by determining the entropy generation rates. New aspects for the branchedflows are an additional parameter, the splitting ratio, and the fact that there is an energy transfer between the single branches that has to be accounted for appropriately. It turns out that this energy transfer changes the total head in each flow brach in addition to a sole loss of total head. Therefore, the coefficients should be named head change coefficients when this effect occurs. As an example the flow through a T-shaped junction is considered, for which head loss coefficients are determined for both branches and discussed with respect to their physical meaning.
DDC Class
600: Technik
620: Ingenieurwissenschaften