Analysis of Steam Condensation Heat Transfer with a Noncondensable Gas in a Vertical Condenser Tube

2008 ◽  
Vol 163 (2) ◽  
pp. 261-272 ◽  
Author(s):  
Kwon-Yeong Lee ◽  
Moo Hwan Kim
Keyword(s):  
Heat Transfer ◽  
Condensation Heat Transfer ◽  
Condenser Tube ◽  
Steam Condensation ◽  
Noncondensable Gas

A Mechanistic Condensation Model for a Passive Condenser System

2005 ◽  
Author(s):  
Seungmin Oh ◽  
Shripad T. Revankar
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Flow Rate ◽  
Transfer Rate ◽  
Mass Fraction ◽  
Condensation Heat Transfer ◽  
Condenser Tube ◽  
Noncondensable Gas ◽  
System Pressure ◽  
Condensation Heat Transfer Coefficient

An experimental study is conducted and a mechanistic model is developed to investigate the effect of noncondensable gas in a passive condenser system. A vertical condenser tube was submerged in a water pool where the heat from the condenser tube was removed through boiling heat transfer. Data was obtained for various process parameters such as inlet steam flow rate, noncondensable gas mass fraction, and system pressure. Degradation of the condensation with noncondensable gas was investigated, where condensation heat transfer coefficient and heat transfer rate decrease with the noncondensable gas. It was found that the condensation heat transfer rate is enhanced by increasing the inlet steam flow rate and the system pressure. A mechanistic condensation correlation is developed which contains the major heat transfer components in its functional relationships. The heat transfers for the film region and the gas region sensible heat were modeled with the modified Nusselt solution and the single phase heat transfer correlations, respectively. The gas region condensation was correlated with bulk noncondensable mass fraction, gas region Reynolds number, and Jakob number. New correlation was compared with available experimental data and models. Mean errors of the correlation were found to be 4.7% and 13.4% for the tube average and the local condensation heat transfer coefficient, respectively.

scholarly journals The Investigation on Heat Transfer Characteristics of Steam Condensation in Presence of Noncondensable Gas under Natural Convection

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Xizhen Ma ◽  
Jiang Ma ◽  
Heng Tong ◽  
Haijun Jia
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Natural Convection ◽  
Transfer Coefficient ◽  
Molar Fraction ◽  
Condensation Heat Transfer ◽  
Heat Transfer Characteristics ◽  
Steam Condensation ◽  
Noncondensable Gas ◽  
Condensation Heat Transfer Coefficient

The NHR-200 reactor in China adopts the noncondensable gas self-stabilizing control and the noncondensable gas used for pressure stabilization control can weaken steam condensation heat transfer in the integrated steam-gas pressurizer. A condensation experimental system was established and the heat transfer characteristics of steam-nitrogen and steam-argon condensation under natural convection had been investigated. The pressure ranged from 0.516 to 5.10 MPa. The distributions of nitrogen and argon in the steam/gas mixture were obtained in the experiments, and the results showed that nitrogen and argon were evenly distributed in the steam under different pressure, respectively. The effects of heat transfer temperature difference had also been investigated and it is found that the total heat transfer coefficient difference had little influence on the total condensation heat transfer coefficient. However, the steam condensation heat transfer coefficient decreased with the increase of the degree of supercooling of the wall. The condensation heat transfer coefficient was reduced by approximately 0.11 kW/(m2·K) as the degree of supercooling of the wall changed from 14°C to 36°C. The condensation heat transfer coefficient also decreased with the mass/molar fraction of noncondensable gas increasing and a certain difference between the effect of the mass fraction of noncondensable gas and the effect of the molar fraction of noncondensable gas was discussed in this paper.

Effect of Surface Inclination on Filmwise Condensation Heat Transfer During Flow of Steam–Air Mixtures

2020 ◽  
Vol 12 (4) ◽  
Author(s):  
Abhinav Bhanawat ◽  
Mahesh Kumar Yadav ◽  
Maneesh Punetha ◽  
Sameer Khandekar ◽  
Pavan K. Sharma
Keyword(s):  
Heat Transfer ◽  
Inclination Angle ◽  
Horizontal Surface ◽  
Condensation Heat Transfer ◽  
Experimental Program ◽  
Steam Condensation ◽  
Flat Plates ◽  
Surface Inclination ◽  
Pure Steam ◽  
Effect Of Surface

Abstract Empirical/semi-empirical correlations are available in the literature to quantify the effect of several major parameters, like bulk pressure, non-condensable gas mass fraction, and wall subcooling, on condensation heat transfer coefficient (HTC). However, despite numerous applications of condensation on inclined flat plates, there is a lack of understanding of the effect of surface inclination on condensation heat transfer. Accordingly, a dedicated experimental program was undertaken to investigate the effect of surface inclination angle on filmwise steam condensation. Experiments were performed at different bulk pressures (1.7–4.2 bar absolute) and steam-air mass fractions (ranging from pure steam, i.e., 0% to 40% w/w air), with the steam-air mixture flowing over a flat test plate (Re range, 4200–4800). In each run, the inclination angle of the test surface was varied from −90 deg (condensation underneath the horizontal surface, facing downward) to +90 deg (condensation over the horizontal surface, facing upward) in increments of 15–20 deg (inclination angle θ measured from vertical). The results reveal an intriguing trend: for pure steam condensation, the HTCs decrease as the plate is inclined in either direction from the vertical, and the variation is nearly symmetric for both upward- and downward-facing configurations. On the other hand, for steam condensation in the presence of air, the HTCs decrease monotonically for upward-facing configurations, while they increase slightly (10–20%), and decrease subsequently (for θ < −70 deg) for downward-facing cases. Finally, the HTCs for inclined orientations are compared with the HTC in the standard vertical configuration to quantify the effect of inclination angle.

Prediction of Bundle Shell Side Condensation Heat Transfer Coefficient

2008 ◽  
Author(s):  
Tailian Chen
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Reasonable Agreement ◽  
Condensation Heat Transfer ◽  
Condenser Tube ◽  
Shell Side ◽  
3 Dimensional ◽  
Design Engineers ◽  
Condensation Heat Transfer Coefficient

Prediction of condenser bundle performance is of great interest to chiller design engineers and tube developers as well. Depending on their locations in a condenser bundle, tubes are subjected to inundation or flooding of condensate coming from those above them. The tubes located in the top portion of the bundle are not or slightly inundated whereas the tubes located deep in the bundle experience larger degree of inundation; those in the bundle bottom are the most severely inundated. For a condenser bundle to have good performance, it is necessary for the tubes to perform well in both non-inundated and inundated conditions. In this paper, the outside condensation heat transfer coefficient and its sensitivity to inundation for a condenser tube of enhanced 3-dimensional (3D) outside fins were measured. Based on the single tube measurements, shell side condensation performance of a condenser bundle was predicted. The predicted bundle outside heat transfer coefficient has a reasonable agreement with that of a condenser tested in a 500-ton chiller.

Sign in / Sign up

Export Citation Format

Share Document