Heat Transfer Characteristics of Condensation and Flow Regime in Horizontal Rectangle Channel of Multi-Channel Cylinder Dryer[J]. 2017, 51(4): 116-121.
DOI:
Heat Transfer Characteristics of Condensation and Flow Regime in Horizontal Rectangle Channel of Multi-Channel Cylinder Dryer[J]. 2017, 51(4): 116-121.DOI: 10.7652/xjtuxb201704018.
Heat Transfer Characteristics of Condensation and Flow Regime in Horizontal Rectangle Channel of Multi-Channel Cylinder Dryer
The phenomenon of steam condensation within a horizontal rectangle channel with one-side cooling in multi-channel cylinder dryer is experimentally studied to investigate the characteristics of steam condensing in the multi-channel cylinder dryer
to improve the efficiency and to reduce the energy consumption of paper industry. Experiments are conducted via the visualization method under the quality of 0.2-0.8 and mass flux of 20-50 kg?m
-2
?s
-1
. Four flow patterns
including annular
wave
slug and plug flows
are observed. The slug flow
plug flow and wave flow are observed at low mass flux
the wave flow and annular flow are observed at high mass flux with
a low steam quality
while the slug and plug flows are not found during the entire condensation process. It is found that the observed flow patterns agree well with Tandon's flow pattern map. The effects of quality and mass flux on condensing heat transfer are analyzed. The experimental results show that the effect of low mass flux(G
<
35 kg?m
-2
?s
-1
)on condensing heat transfer coefficient can be ignored
and the condensing heat transfer coefficient increases obviously with increasing quality and high mass flux. Four kinds of correlations are employed to predict the coefficients of condensing heat transfer
and the result reveals that Cavallini's correlation agrees with the experimental results relatively well.
关键词
Keywords
references
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