Heat Transfer in Direct Contact Condensation of Steam to Subcooled Water Spray

2001 ◽  
Vol 123 (4) ◽  
pp. 703-710 ◽  
Author(s):  
Minoru Takahashi ◽  
Arun Kumar Nayak ◽  
Shin-ichi Kitagawa ◽  
Hiroyuki Murakoso
Keyword(s):  
Heat Transfer ◽  
Flow Direction ◽  
Condensation Heat Transfer ◽  
Saturated Steam ◽  
Internal Circulation ◽  
Conduction Model ◽  
Subcooled Water ◽  
Hollow Cone Spray ◽  
Contact Condensation ◽  
Condensation Heat Transfer Coefficient

The condensation heat transfer of saturated steam to a hollow-cone spray of subcooled water was investigated experimentally and analytically. The spray water temperature rose more steeply in flow direction than those in the previous studies, because of the use of smaller thermocouple which was capable of measuring the temperature in a thin water sheet and water droplets more accurately. The result of the condensation heat transfer coefficient suggested the breakup of the water sheet into droplets. A pure conduction model underpredicted the heat transfer in the sheet region significantly, which was better predicted by considering turbulence in the sheet. The heat transfer in the droplet region was well estimated by considering internal circulation and mixing inside the droplets.

An Analytical Model to Predict Condensation of R-410A in a Horizontal Rectangular Channel

2000 ◽  
Vol 122 (3) ◽  
pp. 613-620 ◽  
Author(s):  
Z. Guo ◽  
N. K. Anand
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Analytical Model ◽  
Rectangular Channel ◽  
Weighted Average ◽  
Condensation Heat Transfer ◽  
Mean Deviation ◽  
Transfer Coefficients ◽  
Condensation Heat Transfer Coefficient

An analytical model to predict condensation heat transfer coefficient in a horizontal rectangular channel was developed. The total local condensation heat transfer coefficient was represented as the weighted average of heat transfer coefficients for each wall. The analytical predictions compared well with the experimental data on the condensation of R-410A in a rectangular channel. The mean deviation was 6.75 percent. [S0022-1481(00)00503-X]

Experimental Apparatus for Measuring in Tube Condensation Heat Transfer Coefficient and Pressure Drop Using Smooth and Micro-Fin Tubes for HFC Refrigerants

2008 ◽  
Author(s):  
Pradeep A. Patil ◽  
S. N. Sapali
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Condensation Heat Transfer ◽  
Test Facility ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Fin Tube ◽  
Condensation Heat Transfer Coefficient

An experimental test facility is designed and built to calculate condensation heat transfer coefficients and pressure drops for HFC-134a, R-404A, R-407C, R-507A in a smooth and micro-fin tube. The main objective of the experimentation is to investigate the enhancement in condensation heat transfer coefficient and increase in pressure drop using micro-fin tube for different condensing temperatures and further to develop an empirical correlation for heat transfer coefficient and pressure drop, which takes into account the micro-fin tube geometry, variation of condensing temperature and temperature difference (difference between condensing temperature and average temperature of cooling medium). The experimental setup has a facility to vary the different operating parameters such as condensing temperature, cooling water temperature, flow rate of refrigerant and cooling water etc and study their effect on heat transfer coefficients and pressure drops. The hermetically sealed reciprocating compressor is used in the system, thus the effect of lubricating oil on the heat transfer coefficient is taken in to account. This paper reports the detailed description of design and development of the test apparatus, control devices, instrumentation, and the experimental procedure. It also covers the comparative study of experimental apparatus with the existing one from the available literature survey. The condensation and pressure drop of HFC-134a in a smooth tube are measured and obtained the values of condensation heat transfer coefficients for different mass flux and condensing temperatures using modified Wilson plot technique with correlation coefficient above 0.9. The condensation heat transfer coefficient and pressure drop increases with increasing mass flux and decreases with increasing condensing temperature. The results are compared with existing available correlations for validation of test facility. The experimental data points have good association with available correlations except Cavallini-Zecchin Correlation.

Study on Direct Condensation Heat Transfer of Steam on to Subcooled Water

2004 ◽  
Vol 2004.3 (0) ◽  
pp. 235-236
Author(s):  
Yasuo KOIZUMI ◽  
Hiroyasu OHTAKE ◽  
Naoki YAMASHITA ◽  
Tohru MIYASHITA ◽  
Michitsugu MORI
Keyword(s):  
Heat Transfer ◽  
Condensation Heat Transfer ◽  
Subcooled Water ◽  
Direct Condensation

Condensation Pressure Drop and Heat Transfer in 5-mm-OD Micro-Fin Tubes

2012 ◽  
Author(s):  
Wei Li ◽  
Dan Huang ◽  
Zan Wu ◽  
Hong-Xia Li ◽  
Zhao-Yan Zhang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Heat Transfer Enhancement ◽  
Condensation Heat Transfer ◽  
Transfer Enhancement ◽  
Mass Fluxes ◽  
Fin Tubes ◽  
Condensation Heat Transfer Coefficient

An experimental investigation was performed for convective condensation of R410A inside four micro-fin tubes with the same outside diameter (OD) 5 mm and helix angle 18°. Data are for mass fluxes ranging from about 180 to 650 kg/m2s. The nominal saturation temperature is 320 K, with inlet and outlet qualities of 0.8 and 0.1, respectively. The results suggest that Tube 4 has the best thermal performance for its largest condensation heat transfer coefficient and relatively low pressure drop penalty. Condensation heat transfer coefficient decreases at first and then increases or flattens out gradually as G decreases. This complex mass-flux effect may be explained by the complex interactions between micro-fins and fluid. The heat transfer enhancement mechanism is mainly due to the surface area increase over the plain tube at large mass fluxes, while liquid drainage and interfacial turbulence play important roles in heat transfer enhancement at low mass fluxes. In addition, the experimental data was analyzed using seven existing pressure-drop and four heat-transfer models to verify their respective accuracies.

Research on R245fa Condensation Heat Transfer Characteristic Inside Horizontal Tubes

2016 ◽  
Author(s):  
Shengchun Liu ◽  
Wenkai Zhang ◽  
Ziteng Dong
Keyword(s):  
Heat Transfer ◽  
High Efficiency ◽  
Transfer Characteristic ◽  
Condensation Heat Transfer ◽  
Two Phase ◽  
Horizontal Tubes ◽  
Copper Pipe ◽  
Practical Engineering ◽  
Inner Diameter ◽  
Condensation Heat Transfer Coefficient

Condensation heat transfer of R245fa in horizontal copper pipe is studied in this paper. In the experimental study, the pipe inner diameter is 4.38 mm, the condensing temperature range from 50∼60°C, mass flow rate ranges from 3.132kg/h to 11.988kg/h, and inlet ranges from 0.89∼1. The research results indicate that the condensation coefficient is rose with the condensing; and it will rise when the inlet quality ranges from 0.89 to 1. Experimental value and the existing two-phase flow correlation are compared in this paper. It shows that the condensation heat transfer coefficient predicted by Haraguchi correlation has a high accuracy relatively. The research provides a foundation to promote development of microchannel high efficiency heat exchanger and it is useful to practical engineering.

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