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Critical mass flow rate through capillary tubes

Nouri Borujerdi, A ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1115/FEDSM-ICNMM2010-30250
  3. Abstract:
  4. This paper presented a numerical study that predicts critical mass flow rate, pressure, vapor quality, and void fraction along a very long tube with small diameter or capillary tub under critical condition by the drift flux model. Capillary tubes are simple expansion devices and are necessary to design and optimization of refrigeration systems. Using dimensional analysis by Buckingham's π theory, some generalized correlations are proposed for prediction of flow parameters as functions of flow properties and tube sizes under various critical conditions. This study is performed under the inlet pressure in the range of 0.8 ≤ pin ≤ 1.5Mpa, subcooling temperature between 0 ≤ ΔTsub ≤10 °C. The tube diameter is in the range of 0.5 ≤ D ≤ 1.5mm and tube length between 1 ≤ L ≤ 2m for water, ammonia, refrigerants R-12, R-22 and R- 134 as working fluids. Comparison between the results of the present work and some experimental data indicates a good agreement. Cluster of data close to the fitted curves also shows satisfactory results
  5. Keywords:
  6. Capillary tube ; Drift flux model ; Numerical method ; Two-phase flow ; Critical condition ; Critical mass ; Design and optimization ; Dimensional analysis ; Dimensionless analysis ; Expansion devices ; Experimental data ; Flow parameters ; Flow properties ; Generalized correlation ; Inlet pressures ; Long tubes ; Numerical studies ; Refrigeration system ; Subcooling temperature ; Tube diameters ; Tube length ; Tube size ; Vapor quality ; Working fluid ; Capillary tubes ; Flow rate ; Fluids ; Mass transfer ; Microchannels ; Numerical methods ; Pipe flow ; Refrigeration ; Tubes (components) ; Two phase flow ; Void fraction ; Inlet flow
  7. Source: American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FEDSM, 1 August 2010 through 5 August 2010 ; Volume 1, Issue PARTS A, B AND C , 2010 , Pages 51-56 ; 08888116 (ISSN) ; 9780791849484 (ISBN)
  8. URL: http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1621052