Experimental Study of Film Condensation From Steam-Air Mixtures Flowing Downward Over a Horizontal Tube

1974 ◽  
Vol 96 (1) ◽  
pp. 83-88 ◽  
Author(s):  
J. W. Rauscher ◽  
A. F. Mills ◽  
V. E. Denny
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Theoretical Analysis ◽  
Mass Fraction ◽  
Horizontal Tube ◽  
Forced Flow ◽  
Film Condensation ◽  
Air Mass ◽  
Average Value ◽  
Pure Steam

Experiments have been performed to study the effects of air on filmwise condensation from steam-air mixtures undergoing forced flow over a 3/4 in. OD horizontal tube. Local condensation rates at the stagnation point are reported for saturation temperatures of 100–150 deg F, bulk to wall temperature differences of 3–30 deg F, bulk air mass fraction 0–7 percent and oncoming vapor velocity 1–6 ft/sec. For pure steam the average value of q/qNu, where qNu is the Nusselt result, was 0.98 ± 0.10, which compares favorably with the value of 1.04 predicted by a theory which accounts for vapor drag. For steam-air mixtures the reduction in heat transfer was found to be in excellent agreement with the theoretical analysis of Denny and South; the average discrepancy in q/qNu was −2.7 percent, while the maximum was 7.1 percent.

Experimental Study of Pure Steam and Steam-Air Mixture Condensation on a Vertical Chrome-Plated Tube

2020 ◽  
Author(s):  
Zesheng Niu ◽  
Guangming Fan ◽  
Jie Cheng ◽  
Wei Li
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Coating Thickness ◽  
Total Pressure ◽  
Mass Fraction ◽  
Air Mass ◽  
Chrome Coating ◽  
Pure Steam ◽  
Condensation Heat Transfer Coefficient

Abstract To investigate the heat transfer characteristics of the chrome-plated tube and hope it could be used on the internal heat exchanger of passive containment cooling system (PCS), an experimental investigation has been conducted. In this experiment, a series of steam condensation experiments are performed under pure steam and steam-air mixed conditions over chrome-plated tube for a variety of chromium coating thickness (1μm and 10μm), total pressure, air mass fraction and wall subcooling. Condensation heat transfer coefficient was obtained for the total pressure ranging from 0.2 MPa to 0.4 MPa, air mass fraction ranging from 0.10 to 0.71, and wall subcooling from 10°C to 70°C. Moreover, the designed visualization experimental device makes the experimental phenomenon can be directly observed through the observation window. Under the pure steam condition, the results show that droplet condensation and filmwise condensation is co-existed on both two kinds of chrome-plated tubes, the chrome coating thickness of 10μm tube shows better heat transfer ability. Under the steam-air mixed condition, the condensation heat transfer coefficient of both two kinds of tubes increases with total pressure, and decrease with the air mass fraction and wall subcooling, while the influence of chrome coating thickness on heat transfer is no longer noticeable. The results also indicate that the thickness of the chromium coating will affect the surface microstructure of the chrome-plated tube and then affect the heat transfer ability of the chrome-plated tube.

An Analytical Study of Laminar Film Condensation: Part 2—Single and Multiple Horizontal Tubes

1961 ◽  
Vol 83 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Michael Ming Chen
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Horizontal Tube ◽  
Vertical Tube ◽  
Film Condensation ◽  
Transfer Coefficients ◽  
Inertia Effects ◽  
Horizontal Tubes ◽  
Laminar Film ◽  
Laminar Film Condensation

The boundary-layer equations for laminar film condensation are solved for (a) a single horizontal tube, and (b) a vertical bank of horizontal tubes. For the single-tube case, the inertia effects are included and the vapor is assumed to be stationary outside the vapor boundary layer. Velocity and temperature profiles are obtained for the case μvρv/μρ ≪ 1 and similarity is found to exist exactly near the top stagnation point, and approximately for the most part of the tube. Heat-transfer results computed with these similar profiles are presented and discussed. For the multiple-tube case, the analysis includes the effect of condensation between tubes, which is shown to be partly responsible for the high observed heat-transfer rate for vertical tube banks. The inertia effects are neglected due to the insufficiency of boundary-layer theory in this case. Heat-transfer coefficients are presented and compared with experiments. The theoretical results for both cases are also presented in approximate formulas for ease of application.

Sea Water Distillatory Using Rising Film on the Fluted Surface of Horizontal Tubes

2006 ◽  
Author(s):  
Yan Li ◽  
Ning Mei ◽  
Yesheng Sun
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Theoretical Analysis ◽  
Numerical Solution ◽  
Temperature Difference ◽  
Sea Water ◽  
Flow Characteristics ◽  
Horizontal Tube ◽  
Transfer Model ◽  
Horizontal Tubes

The purpose of this study is to investigate the mechanism of the seawater distillatory using rising liquid thin film on the fluted surface of a horizontal tube. By analyzing the formation of the rising film, a process of the HRF evaporators was designed to analysis the efficiency of the system. The numerical solution of heat transfer model shows that the temperature difference of HRF in one effect is lower than that of HFF. The behaviors of the flow characteristics were discussed. The results show that the rising liquid thin film could be formed when the rate of roll equaled 15°. The results from theoretical analysis suggest that seawater distillatory using rising liquid thin film on the fluted surface of a horizontal tube was especially suitable for the wobble environment.

Film Condensation of Refrigerant-113 and Ethanediol on a Horizontal Tube—Effect of Vapor Velocity

1984 ◽  
Vol 106 (3) ◽  
pp. 524-530 ◽  
Author(s):  
W. C. Lee ◽  
S. Rahbar ◽  
J. W. Rose
Keyword(s):  
Heat Transfer ◽  
Ethylene Glycol ◽  
Horizontal Tube ◽  
Low Pressure ◽  
Film Condensation ◽  
Vapor Velocity

Heat transfer measurements are reported for condensation of refrigerant-113 and ethanediol (ethylene glycol) on a single horizontal tube with vertical downflow. For refrigerant-113, vapor velocities up to around 6 m/s were obtained, while for ethanediol, velocities in excess of 100 m/s were obtained at low pressure. The results are compared with those of earlier investigators and with theory.

Experimental study on film condensation of superheated vapour on a horizontal tube

2015 ◽  
Vol 61 ◽  
pp. 153-162 ◽  
Author(s):  
Zhixiang Zhao ◽  
Yanzhong Li ◽  
Lei Wang ◽  
Kang Zhu ◽  
Fushou Xie
Keyword(s):  
Experimental Study ◽  
Horizontal Tube ◽  
Film Condensation
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