Session: 11-02 Severe accident mitigation phenomena

Paper Number: 135388

135388 - Numerical Simulation of Single/two-Phase Flow in a Stratified Porous Bed 

Abstract: 

The effect of coolability on a debris bed formed in Fuel Coolant Interactions (FCI) has great significance to nuclear reactor safety due to the failures of all cooling systems producing severe core melting accidents in light water reactors. The molten core fuel (corium) would interact with the coolant to break up into a porous debris bed. The flow characteristics of single and/or two-phase flow in a porous bed with stratification configurations have been studied numerically on a two-layer porous bed packed with two different-sized particles. The numerical investigations based on computational fluid dynamics simulation (ANSYS software) are also performed to simulate the variation of velocities and pressures in a two-layer porous bed, especially in the interface area of two layers. The primary objective is to enrich our understanding of two-phase flow characteristics within a stratified porous bed, encompassing distinct porosity variations on both sides and within different layers of the medium. The complex interaction between the flow phases within the stratified porous structure is investigated using advanced computational models for multiphase flow and porous media. Special attention is given to the variations in stratified porosity to match the complex geometries encountered in nuclear reactor scenarios. The emphasis is placed on comprehending the impact of different layers within the porous medium and recognizing their role in shaping coolant flow patterns. The influence of phase flow type, different porosity between two layers, and the speed of the flow on velocity distributions and pressure drop in a two-layer porous bed has been investigated. The results indicated that the pressure drops remain almost constant with a wide range of water velocity in the two layers of the radial stratified bed. When fluids flow up through the radially stratified porous layers, a lateral flow formed This flow from the low permeability layer to the high permeability layer causes a reduction in the pressure drop in the low permeability layer and an increase in the high permeability layer. In addition, there is lateral flow in a two-layer porous bed, and certain fluids from the smaller-size particle layer may flow laterally into the larger-size particle layer due to the increased porosity in the larger-size particle layer. The majority of the lateral flow occurs in the first portion of the test section when fluids move up the two-layer porous bed. It is thought that lateral flow causes pressure drop to decrease in the smaller particle layer while increasing in the bigger particle layer.

Presenting Author: aimad bouloudenine xian jiaotong university

Presenting Author Biography: Greetings, I am AIMAD, a dedicated professional with a background in mechanical engineering, having completed my master's degree in 2019. Over the subsequent three years, I engaged in meaningful work, honing my skills and contributing to the field.
Driven by a thirst for knowledge and a desire to make a substantial impact in the realm of power and energy, I embarked on a Ph.D. journey at Xian Jiaotong University in China in 2022. This decision reflects my commitment to academic excellence and the pursuit of expertise in a field that holds immense potential for global advancement.

Authors:

aimad bouloudenine xian jiaotong university
Liangxing Li Xi’an Jiaotong University
Zutao Xiang Xi’an Jiaotong University
Shang Shi Xi’an Jiaotong University
Muhammad Abu Bakar Xi’an Jiaotong University