# Numerical Investigation of Hydrogen Leakage Quantification and Dispersion Characteristics in Buried Pipelines

## TL;DR

This study uses computer simulations to understand how hydrogen leaks and spreads from buried pipelines, offering insights for safer hydrogen energy systems.

## Contribution

The paper introduces a predictive model for hydrogen dispersion in soil using SQP optimization with high accuracy.

## Key findings

- Hydrogen migration is limited for leakage orifices smaller than 2 mm regardless of orientation.
- Dispersion patterns remain stable under low-pressure and minimal thermal gradients.
- Higher pressure, soil porosity, and particle size increase dispersion intensity, while burial depth reduces it.

## Abstract

As a clean energy carrier, hydrogen is essential for global low-carbon energy transitions due to its unique combination of safe transport properties and energy density. This investigation employs computational fluid dynamics (ANSYS Fluent) to systematically characterize hydrogen dispersion through soil media from buried pipelines. The research reveals three fundamental insights: First, leakage orifices smaller than 2 mm demonstrate restricted hydrogen migration regardless of directional orientation. Second, dispersion patterns remain stable under both low-pressure conditions (below 1 MPa) and minimal thermal gradients, with pipeline temperature variations limited to 63 K and soil fluctuations under 40 K. Third, dispersion intensity increases proportionally with higher leakage pressures (exceeding 1 MPa), greater soil porosity, and larger particle sizes, while inversely correlating with burial depth. The study develops a predictive model through Sequential Quadratic Programming (SQP) optimization, demonstrating exceptional accuracy (mean absolute error below 10%) for modeling continuous hydrogen flow through moderate-porosity soils under medium-to-high pressure conditions with weak inertial effects. These findings provide critical scientific foundations for designing safer hydrogen transmission infrastructure, establishing robust risk quantification frameworks, and developing effective early-warning systems, thereby facilitating the practical implementation of hydrogen energy systems.