scholarly journals Visualization of Steam-Water Flow in Direct Contact Condensation Process at High Velocity Ratio

1987 ◽  
Vol 7 (Supplement) ◽  
pp. 85-88
Author(s):  
Yutaka Hanaoka ◽  
Kazuo Maeno ◽  
Syuuichi Nagata
Keyword(s):  
Water Flow ◽  
High Velocity ◽  
Direct Contact ◽  
Velocity Ratio ◽  
Condensation Process ◽  
Contact Condensation

Experimental and Numerical Research on Steam Direct Contact Condensation Process in Automatic Depressurization System of AP1000

2020 ◽  
Author(s):  
Yuhao Zhang ◽  
Li Feng ◽  
Zhimin Qiu ◽  
Jingpin Fu ◽  
Daogang Lu
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Direct Contact ◽  
Cfd Simulation ◽  
Condensation Process ◽  
Validation Data ◽  
Numerical Work ◽  
Pressurized Water ◽  
Temperature And Pressure ◽  
Contact Condensation

Abstract In the third generation pressurized water reactor AP1000 plant, the Automatic Depressurization System (ADS) is one of the most important passive safety system. However, the steam Direct Contact Condensation (DCC) microscopic mechanisms are very complicated, which are not very clear yet. Moreover, the high-pressure and high-temperature experiment is very expensive to be conducted for many different test conditions. So in the present work, both the experimental and numerical methods are employed to investigate the steam DCC behavior. The steam DCC experimental bench has been built up, and the key parameters including the flow patterns and steam core temperature distributions are measured to provide validation data for the numerical results. In aspect of the numerical work, CFD simulation on the steam condensation is conducted. The heat and mass transfer process is simulated through the three-dimension commercial software FLUENT 16.0. Some of the key heat and mass transfer correlations are added by User Defined Function (UDF). The key parameters including the condensation steam fraction, temperature, and pressure, etc. are analyzed, which reflect the major heat transfer characteristics. According to the results, the expansion-compression-steam tail could be observed in both the numerical and experimental results. In essential, the steam fraction, temperature, and pressure distributions are determined by the equilibrium and transformation between the thermal dynamic energy and kinetic energy. The results provide working references for the practical ADS steam spraying condensation process in AP1000 reactor.

scholarly journals Hydrodynamics of Direct Contact Condensation Process in Desuperheaters

2021 ◽  
Author(s):  
Afrasyab Khan ◽  
Khairuddin Sanaullah ◽  
Andrew Ragai Henry Rigit ◽  
Atta Ullah
Keyword(s):  
Nozzle Exit ◽  
Direct Contact ◽  
Fossil Fuels ◽  
Steam Injection ◽  
Condensation Process ◽  
Axial Distance ◽  
Local Circulation ◽  
Environmental Implications ◽  
Injection Duration ◽  
Contact Condensation

Abstract Due to the global warming and environmental implications, the focus of household heating has shifted from fossil fuels towards environmentally friendly and renewable sources. Desuperheaters have been found an attractive option as a domestic provision for the warm water; they used steam induced direct contact condensation (DCC) as the major means to warm the water. The present study has been an attempt to investigate the hydrodynamics in the Desuperheater vessel experimentally, when the pressurized pulsating steam was injected into the vessel, where, the steam jet interacted co-currently with the slow-moving water. Visual flow visualization provided an overall flow picture that showed a circulation region when the pulsating steam was injected into the slow co-currently moving water and the peaked vorticity corresponded to the steam injection duration varying from 10-60 seconds. An array of 7 Hot Film Anemometers (HFA) was traversed axially and radially to determine the velocity fluctuations at 0 – 20 cm from the steam's nozzle exit. Vortical structures were obtained that corresponded to the entrainment of the steam with the surrounding cocurrently moving water. The circulation regions were thus exhibited in relation to the steam's injection durations as well as the downstream axial distance of 2 cm and 15 cm from the nozzle exit, which showed that the core local circulation at 2 cm, lost 75-79% of its circulation at 15 cm downstream of the nozzle exit.

Experimental Study on Chugging Condensation Regime of Steam Direct Contact Condensation in Water Flow in a Tee Junction

2017 ◽  
Author(s):  
Wang Jie ◽  
Lu Tao ◽  
Liu Bo
Keyword(s):  
Water Flow ◽  
Direct Contact ◽  
High Speed ◽  
Branch Pipe ◽  
Phase Interface ◽  
Nuclear Industry ◽  
Saturated Steam ◽  
Two Phase ◽  
Tee Junction ◽  
Contact Condensation

The phenomenon of direct contact condensation (DCC) is encountered in both the nuclear industry and conventional industry and it is intimately associated with safety operation of relevant equipment. Studies on steam jet discharged directly into a stagnant water pool have been studied extensively; however, they are sparse for direct contact condensation of steam in sub-cooled water in pipes. In this paper, the experiments were performed to study the direct contact condensation of low mass flux saturated steam discharged into sub-cooled water flow in a Tee junction. By using high-speed camera, we investigated chugging condensation characteristics including two-phase interface movements. It is can be seen from the experiment results that, for chugging, steam plume and surrounding sub-cooled water undergo the following process: steam plume grows to the maximum, then steam plume becomes smaller due to condensation, and finally, water enters the vertical branch pipe and steam ejects from the vertical branch pipe again.

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