Open Access

ARTICLE

Numerical Analysis of Non-Uniform Pollutant Distribution in an Internal Space of Tank and the Efficacy of an Active Purification Strategy

Xiaolong Li, Hui Chen, Yingwen Liu, Peng Yang^*
Key Laboratory of Thermo-Fluid Science and Engineering of MOE, School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an, 710049, China
* Corresponding Author: Peng Yang. Email:
(This article belongs to the Special Issue: Microscale Heat and Mass Transfer and Efficient Energy Conversion)

Frontiers in Heat and Mass Transfer https://doi.org/10.32604/fhmt.2025.070537

Received 18 July 2025; Accepted 11 October 2025; Published online 07 November 2025

Abstract

Hazardous gas intrusion in tightly sealed and geometrically complex confined spaces, such as armored tanks, poses a critical threat to occupant health. The intricate internal structure of these systems may lead to non-intuitive pollutant transport pathways. However, the spatial and temporal evolution of these structures, as well as the intrinsic mechanisms of the purification systems, remain poorly elucidated. In this study, a high-fidelity, transient three-dimensional computational fluid dynamics (CFD) model was developed to simulate the leakage and dispersion of carbon monoxide (CO) and nitrogen dioxide (NO₂) using the RNG k-ε turbulence model. Scenarios with and without an active purification system were systematically investigated under four leakage rate conditions: 0.33, 0.66, 1.32, and 2.64 m·s⁻¹. Our results reveal that, flow recirculation driven by the compartment’s geometry leads to the formation of stable, high-concentration “hazard zones”. Following the activation of the purification system, decreases from 1 to 0.1, demonstrating that the primary value of the purification system lies in homogenizing the internal flow field and minimizing localized hazardous zones. At leakage rates below 1.32 m/s, the purification system ensures pollutant concentrations at all monitoring points are effectively controlled below limitation. When single-pass purification efficiency increases from 25% to 30%, pollutant concentrations at critical monitoring points decrease by approximately 30%. This work provides crucial mechanistic insights and a quantitative basis for the design of advanced ventilation systems in complex confined environments, advocating a design philosophy shift from simple air exchange to strategic flow-field management.

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Keywords

Hazardous gas; leakage and diffusion; purification strategy; CFD; confined space; flow homogenization

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