Numerical Study on Hydrogen Flow Behavior for Different Connecting Pipe Structures

Abstract

Hydrogen control in the case of severe accidents has been required by nuclear regulations to ensure the integrity of nuclear containment building. Therefore, getting detailed hydrogen flow and distribution is a key issue to resolve the hydrogen risk in containment and compartments. In this study, local hydrogen behavior has been investigated in a multi-subcompartments using Computational Fluid Dynamics method, concerning the local concentration in the multi-subcompartments. The multi-subcompartments containment is represented by four vessels interconnected by pipe. Hydrogen inlet pipe is located in source vessel. The analysis model is built by 3-dimensional Computational Fluid Dynamics code ANSYS-CFX in Cartesian coordinates. Computational domain is discretized in about 47559 cells, 87484 cells and 126388 cells, respectively. Taking a full consideration of the computational time and accurate, the medium mesh scheme is adopted to simulate the hydrogen transport. With standard k-ε turbulence model, the effects of the connecting pipe parameters and direction on hydrogen distribution in the multi-compartments are investigated. Local hydrogen behavior showed remarkably different in simulations with the change of the pipe parameter. Increasing the connection pipe diameter and decreasing the connection pipe length are helpful for helium flow between compartments. Compare with the vertical connection pipe, horizontal connection pipe is not conducive to the diffusion of hydrogen from source compartment to non-source compartment.