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

2021 ◽  
Author(s):  
Yuhao ZHANG ◽  
Li Feng ◽  
Zhimin Qiu ◽  
Jingpin Fu ◽  
Daogang Lu
Keyword(s):  
Direct Contact ◽  
Condensation Process ◽  
Numerical Research ◽  
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.

DIRECT CONTACT CONDENSATION OF FLOWING STEAM ONTO INJECTED WATER

1978 ◽  
Author(s):  
Shigebumi Aoki ◽  
Akira Inoue ◽  
Yoshiyuki Kozawa ◽  
H. Akimoto
Keyword(s):  
Direct Contact ◽  
Contact Condensation

Reduce odor and NH3 emission: condensation of the carbonatation vapors

2017 ◽  
pp. 534-537
Author(s):  
Nico Antens ◽  
Jan L.M. Struijs
Keyword(s):  
Direct Contact ◽  
Waste Heat ◽  
Pilot Scale ◽  
Sugar Production ◽  
Two Stage ◽  
Indirect Contact ◽  
Nh3 Emission ◽  
Emission Limits ◽  
Plant Trials ◽  
Contact Condensation

At beet sugar production, vapors from first and second carbonatation contain a significant amount of odor components, NH3 and waste heat, which are normally directly released into the environment. Due to sustainability motivations, obligations regarding odor nuisance and expected stricter regulations regarding NH3 emission limits, Suiker Unie decided to take measures to reduce emission via the carbonatation vapors. During the 2015 beet campaign, pilot scale plant trials have been performed to investigate the effectiveness of indirect contact and direct contact condensation of these vapors. Based on this experimental work a two-stage gas scrubbing concept was designed: in the first stage main goal is condensing the vapors and reuse the heat of condensation to heat up limed juice, while the actual scrubbing takes place in the second scrubber. This two-stage gas scrubbing installation has been built at the Vierverlaten factory and was started up in the 2016 beet campaign. The background, pilot scale trials, concept of design and achieved reductions in odor and NH3 emission at industrial scale are discussed.

A Physically Based, One-Dimensional Two-Fluid Model for Direct Contact Condensation of Steam Jets Submerged in Subcooled Water

2015 ◽  
Vol 1 (2) ◽  
Author(s):  
David Heinze ◽  
Thomas Schulenberg ◽  
Lars Behnke
Keyword(s):  
Direct Contact ◽  
Two Phase Flow ◽  
Fluid Model ◽  
Interfacial Area ◽  
Phase Flow ◽  
Two Phase ◽  
One Dimensional ◽  
Two Fluid Model ◽  
Contact Condensation ◽  
Two Fluid

A simulation model for the direct contact condensation of steam in subcooled water is presented that allows determination of major parameters of the process, such as the jet penetration length. Entrainment of water by the steam jet is modeled based on the Kelvin–Helmholtz and Rayleigh–Taylor instability theories. Primary atomization due to acceleration of interfacial waves and secondary atomization due to aerodynamic forces account for the initial size of entrained droplets. The resulting steam-water two-phase flow is simulated based on a one-dimensional two-fluid model. An interfacial area transport equation is used to track changes of the interfacial area density due to droplet entrainment and steam condensation. Interfacial heat and mass transfer rates during condensation are calculated using the two-resistance model. The resulting two-phase flow equations constitute a system of ordinary differential equations, which is solved by means of the explicit Runge–Kutta–Fehlberg algorithm. The simulation results are in good qualitative agreement with published experimental data over a wide range of pool temperatures and mass flow rates.

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