Computational Fluid Dynamics Simulation of Direct-Contact Condensation Phenomenon of Vapor Jet in Subcooled Water Tank

Author(s):  
Yu Ji ◽  
Hao-Chun Zhang ◽  
Yi-Ning Zhang ◽  
Xu-Wei Wang ◽  
Yan Quan

The direct-contact condensation (DCC) is a significant phenomenon in a nuclear reactor and its balance facilities, together with some chemical engineering systems. DCC occurs when the vapor is ejected from the nozzle, contacts with subcooled water, and condenses at the interface directly. The DCC phenomenon accompanied with the heat transfer and mass transfer will lead to the temperature and pressure fluctuations in the tank, even some accidents under certain conditions. This paper investigates the transport phenomena concerning the DCC in the subcooled water tank using the computational fluid dynamics (CFD) commercial code, ANSYS-FLUENT, in which the DCC process is simulated with the Euler–Euler framework for two-phase flow, and the simplified Hertz–Knudsen–Schrage relation is adopted to model mass transfer. In the simulation, the flow field and temperature profile are derived. Moreover, the shape and size of the plume jet are also investigated.

Author(s):  
Rajnish K. Calay ◽  
Arne E. Holdo

The Computational Fluid Dynamics (CFD) is now increasingly being used for modeling industrial flows, i.e. flows which are multiphase and turbulent. Numerical modeling of flows where momentum, heat and mass transfer occurs at the interface presents various difficulties due to the wide range of mechanisms and flow scenarios present. This paper attempts to provide a summary of available mathematical models and techniques for two-phase flows. Some comments are also made on the models available in the commercially available codes.


2016 ◽  
Vol 138 (11) ◽  
Author(s):  
Shao-Wen Chen ◽  
Christopher Macke ◽  
Takashi Hibiki ◽  
Mamoru Ishii ◽  
Yang Liu ◽  
...  

In order to study the two-phase flow behaviors of a horizontal bubble plume in a tank, experimental tests along with computational fluid dynamics (CFD) simulations were carried out in this paper. An experimental facility was designed and constructed which allows air–water bubble jet being injected horizontally into a water tank by three-parallel injector nozzles with different gas and liquid superficial velocities (〈jg〉in = 2.7–5.7 m/s and 〈jf〉in = 1.8–3.4 m/s). Two sizes of injector nozzles (D = 0.053 m and 0.035 m) were tested to examine the injector size effect. Important parameters including void fraction, fluid velocity, bubble Sauter mean diameter, and their distributions in the tank were measured and analyzed. In addition to the experimental work, selected flow conditions were simulated with ANSYS CFX 13.0. Compared with the experimental data, the present CFD simulation can predict the general trends of void and flow distributions and the recirculation fluid velocity with an accuracy of ±30%. The present CFD simulation methodology has been validated by the experimental results and can be applied to bubble plume analyses and design.


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