Simulation of the Vapor-Liquid Two-Phase Flow of Evaporation and Condensation

Under the conditions of the actual operation of the nuclear power plant, especially in the drainage system of the heaters, water recycling system, and condensate pump recirculation system, there is a sudden pressure drop after the control valve in the pipeline, which will lead to serious vapor-liquid two-phase flow. Vapor liquid two phase flow can lead to accelerated corrosion in the pipeline. In order to study the influence of vapor liquid two phase flow on the accelerated corrosion of the pipeline, an experimental facility for simulating the operating conditions of the Second Loop was designed and completed. The experimental facility comprises a pressure regulator, high pressure water tank, circulating pump, power heater, low pressure water tank, condensing and cooling system, instrumentation and data acquisition system. The flow characteristics and the corrosion characteristics of the inner wall of the pipe in the flow channel after the control value were studied in the experiments. The flow characteristics include the distribution of water and vapor temperature, pressure drop distribution and void fraction along the flow channel. In the meanwhile, the corrosion rate and surface characteristics of inner wall at different locations were also studied by CCD and SEM. In addition, the influences of pipe material and pipeline geometry on the erosion-corrosion were also studied in the experiments.

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Isothermal two-phase flow of a vapor–liquid system with non-negligible inertial effects

International Journal of Engineering Science ◽

10.1016/j.ijengsci.2011.05.003 ◽

2011 ◽

Vol 49 (9) ◽

pp. 915-933 ◽

Cited By ~ 1

Author(s):

Iacopo Borsi ◽

Lorenzo Fusi ◽

Fabio Rosso Alessandro Speranza

Keyword(s):

Two Phase Flow ◽

Liquid System ◽

Phase Flow ◽

Inertial Effects ◽

Two Phase ◽

Vapor Liquid

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Numerical Simulation of Vapor-Liquid Two-Phase Flow in a Closed Loop Oscillating Heat Pipe

Volume 9: Heat Transfer, Fluid Flows, and Thermal Systems, Parts A, B and C ◽

10.1115/imece2009-12038 ◽

2009 ◽

Cited By ~ 6

Author(s):

Xiangdong Liu ◽

Yingli Hao

Keyword(s):

Mathematical Model ◽

Slug Flow ◽

Annular Flow ◽

Closed Loop ◽

Two Phase Flow ◽

Working Fluid ◽

Phase Flow ◽

Two Phase ◽

Oscillating Heat Pipe ◽

Vapor Liquid

A comprehensive mathematical model including the effects of vapor-liquid interface and surface tension was proposed to describe the vapor-liquid two-phase flow, heat and mass transfer and the phase change process in a closed loop oscillating heat pipe (CLOHP). The vapor-liquid two-phase flow in a typical CLOHP was numerically investigated using the proposed mathematical model and the VOF method. The comparisons between the computational and experimental results indicated that the proposed model could successfully simulate the initial distribution of working fluid, the complex flow patterns during different operation conditions, such as bubbly flow, slug flow, semi-annular/annular flow, back flow, and the flow pattern transitions in the CLOHP. The phenomenon that semi-annular/annular flow and slug flow formed in alternating vertical tubes at the initial stage of working fluid circulation was also simulated successfully. Those results were in good agreement with the experimental observations. The flow and heat transfer of a working fluid in two transition sections, and the effects of heating power on the interval flow patterns, were analyzed based on the numerical simulation. The results showed that the changes of temperature, pressure and flow pattern were obvious in the transition section between adiabatic section and condenser section, where the transition of heat transfer condition occurred. The violent boiling might occur in the evaporator section under the high heating power of 100 W and 120 W. The preliminary results indicated that the mathematical model proposed in present paper could effectively reveal the complex vapor-liquid two-phase flow in CLOHP, which established a basis for the further study of complex working mechanisms of CLOHP and effects of operation parameters.

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