Session: 08-08: Computational Fluid Dynamics (CFD) and Applications - VIII

Paper Number: 135676

135676 - Numerical Investigation on Interphase Interaction and Interplume Effects of Multi-Hole Steam Injection Condensation Based on Ads 1-3 

Abstract: 

The In-containment refueling water storage tank (IRWST) is a critical component of the AP1000 passive residual heat removal system. It houses two essential pieces of equipment: the passive residual heat removal heat exchanger (PRHRHX) and the automatic depressurization system sparger (ADS-Sparger). The tank functions as a heat trap for these components. The PRHRHX is situated on one side of a large, irregularly shaped IRWST. The water in the tank acts as a heat trap, removing waste heat from the reactor core.

The Automatic Depressurization System (ADS) consists of four pressure relief valve stages. Stages 1-3 are connected in parallel with the outlet of the top space of the regulator and are submerged in the built-in material exchange water tank through the sprinkler. Stage 4 of the pressure relief system is directly relieved to the large space of the containment vessel. When stages 1-3 of the ADS are triggered, the high-temperature and high-pressure vapour emitted from the sprinkler is connected with the water in the water tank, resulting in direct contact condensation (DCC) of the vapour. This process of heat exchange is rapid and affects the spraying of high temperature and high pressure vapour and water inside the water tank. The process is violent and affects the condensation effect of the sprayed high temperature and high pressure steam. During DCC, pressure oscillations induced by fluid can pose a threat to the safety of the system and equipment. Furthermore, jet-driven turbulence can cause thermal mixing and stratification in the condensate tank. This process is highly demanding in both experimental and numerical studies due to the complexity of the physics involved.

Multi-hole jets are commonly used in technical applications to cool and depressurize high-temperature and high-pressure steam emissions due to their high heat and mass transfer efficiency. However, existing numerical models do not fully meet simulation needs, particularly under porous circumstances, due to the complexity of steam condensation micromechanics. Previous research has mainly focused on single-pore steam jet DCC. It is important to develop more comprehensive models that can accurately simulate multi-hole steam jet DCC. This work presents a three-dimensional transient numerical simulation of the Direct Contact Condensation (DCC) mechanism and heat transfer characteristics of a multi-hole high-temperature and high-pressure steam jet. The simulation is based on the ADS 1-3 level equipment in IRWST. The model for DCC of multi-hole vapour injection and release is developed using User-Defined Functions (UDFs).

The simulation results show that the developed model can effectively simulate the DCC process of multi-hole vapour jets and the interactions between phases. The numerical simulation in this paper demonstrates that the interaction between steam plumes on the centreline between nozzles significantly affects the thermo-hydrodynamic parameters between the jets in DCC of high-temperature and high-pressure steam. This provides a useful reference for understanding complex heat and mass transfer processes.

 

Presenting Author: Yuhao Zhang North China Electric Power University

Presenting Author Biography: Yuhao Zhang, Associate Professor, School of Nuclear Science and Engineering, North China Electric Power University, winner of the Outstanding Youth Fund of the Natural Science Foundation of Hebei Province, selected for the "2023-2025 Young Talent Lifting Project of Beijing Association for Science and Technology", core member of the outstanding undergraduate education team of Beijing universities, and member of the first youth editorial board of "Atomic Energy Science and Technology"; he is mainly engaged in the research of advanced nuclear reactor power engineering, and has published more than 70 papers, including more than 30 SCI and EI papers as the first/corresponding author, and applied for 10 invention patents; He has won a number of science and technology awards from the Ministry of Education, Beijing Municipality and industry associations.

Authors:

Jibin Xu North China Electric Power University
Hao Zheng China Nuclear Power Engineering Co., Ltd.
Xihao Shen North China Electric Power University
Yuhao Zhang North China Electric Power University
Daogang Lu North China Electric Power University