Numerical Simulation on Interfacial Characteristics in Supersonic Steam–Water Injector Using Particle Model Method

Xianbing Chen,Maocheng Tian,Guanmin Zhang,Houke Liu

doi:10.3390/en12061108

Xianbing Chen, Maocheng Tian + Show 2 more

Open Access

https://doi.org/10.3390/en12061108

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Journal: Energies	Publication Date: Mar 21, 2019
Citations: 5	License type: CC BY 4.0

Affiliation: Shandong University, Beijing Drainage Group (China)

Abstract

Steam–water injectors have been widely applied in various industrial fields because of their compact and passive features. Despite its straightforward mechanical design, the internal two-phase condensing flow phenomena are extremely complicated. In present study, a numerical model has been developed to simulate steam–water interfacial characteristics in the injectors based on Eulerian–Eulerian multiphase model in ANSYS CFX software. A particle model is available for the interphase transfer between steam and water, in which a thermal phase change model was inserted into the model as a CFX Expression Language (CEL) to calculate interphase heat and mass transfer. The developed model is validated against a test case under a typical operating condition. The numerical results are consistent with experimental data both in terms of axial pressure and temperature profiles, which preliminarily demonstrates the feasibility and accuracy of particle model on simulation of gas–liquid interfacial characteristics in the mixing chamber of injector. Based on the dynamic equilibrium of steam supply and its condensation, interfacial characteristics including the variation of steam plume penetration length and steam–water interface have been discussed under different operating conditions. The numerical results show that steam plume expands with steam inlet mass flow rate and water inlet temperature increasing, while it contracts with the increase of water inlet mass flow rate and backpressure. Besides this, the condensation shock position moves upstream with the backpressure increasing.

Highlights

A steam–water injector (SI) is a pump-like device that consumes high-pressure steam to draw in cold water and raise its pressure
The amount of steam supply is represented by steam inlet mass flow rate, while the steam consumption rate is mainly condensed by the entrained water
A numerical model has been developed based on Eulerian–Eulerian multiphase model to simulate the effect of operating conditions on the steam–water contact condensation in SI, in which particle model is used to calculate interphase mass, momentum, and energy transfer due to the interfacial complexity between steam and water

Summary

Introduction

A steam–water injector (SI) is a pump-like device that consumes high-pressure steam to draw in cold water and raise its pressure. The SI has been widely used in the industrial areas for district-heating system [1], Rankine cycle of steam power plants [2], and the passive safety systems of nuclear reactors [3,4,5,6,7,8,9,10]. The passive feature of SI has revived with more and more applications to passive core cooling systems, which can be used for high pressure makeup water supply in advanced light water reactors and high-pressure safety injection system for boiling water reactors. The SI could ensure the heat removal from a nuclear reactor core without electric power supply, fulfilling safety requirements. Due to the efficient transfer of heat, mass and momentum in direct contact condensation (DCC) in mixing chamber, SI can operate efficiently as direct contact feed water heaters [11]

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