In this paper, flow patterns and their transitions for refrigerant R134a boiling in a microfinned helically coiled tube are experimentally observed and analyzed. All the flow patterns occurred in the test can be divided into three dominant regimes, stratified-wavy flow, intermittent flow and annular flow. Experimental data are plotted in two kinds of flow maps, i.e., Taitel and Dukler flow map and mass flux versus vapor quality flow map. The transitions between various flow regimes and the differences from that in smooth straight tube have also been discussed. Martinelli parameter can be used to indicate the transition from intermittent flow to annular flow. The transition from stratified-wavy flow to annular or intermittent flow is identified in the vapor quality versus mass flux flow map. The flow regime is always in stratified-wavy flow for a mass flux less than 100 kg/(m2s). The two-phase frictional pressure drop characteristics in the test tube are also experimentally studied. The two-phase frictional multiplier data can be well correlated by Lockhart-Martinelli parameter. Considering the corresponding flow regimes, i.e., stratified and annular flow, two frictional pressure drop correlations were proposed, and showed a good agreement with the respective experimental data.
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ASME 2006 International Mechanical Engineering Congress and
Exposition
November 5–10, 2006
Chicago, Illinois, USA
Conference Sponsors:
- Heat Transfer Division
ISBN:
0-7918-4785-3
PROCEEDINGS PAPER
Flow Patterns and Pressure Drop for Flow Boiling Inside Microfinned Helically Coiled Tube Available to Purchase
Qinghua Chen,
Qinghua Chen
University of Wisconsin at Milwaukee
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Wenzhi Cui
Chongqing University
Long-Jian Li
Chongqing University
Tien-Chien Jen
Chongqing University
Qinghua Chen
University of Wisconsin at Milwaukee
Quan Liao
University of Wisconsin at Milwaukee
Qinhua Chen
Paper No:
IMECE2006-14573, pp. 303-308; 6 pages
Published Online:
December 14, 2007
Citation
Cui, W, Li, L, Jen, T, Chen, Q, Liao, Q, & Chen, Q. "Flow Patterns and Pressure Drop for Flow Boiling Inside Microfinned Helically Coiled Tube." Proceedings of the ASME 2006 International Mechanical Engineering Congress and Exposition. Heat Transfer, Volume 2. Chicago, Illinois, USA. November 5–10, 2006. pp. 303-308. ASME. https://doi.org/10.1115/IMECE2006-14573
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