Design, experimental validation, and load-dependent numerical assessment of a 1.4 MWth industrial hydrogen burner based on a multi-stage radial hydrogen injection strategy

A 1.4 MWth industrial swirl burner with multi-stage radial hydrogen injection was developed for low-NOx hydrogen combustion with reduced flashback risk. Hydrogen is supplied through central, inner, and outer stages, while air is distributed through independently zoned passages to promote distributed fuel–air interaction and avoid stoichiometric flame cores. Industrial tests at approximately 1.0 MWth were conducted under a blended-fuel condition with 70% H 2 on a thermal-input basis and pure‑hydrogen firing. Stable combustion without flashback or blow-off was achieved. NOx emissions were approximately 30 ppm for the blended case and 39 ppm for pure hydrogen. A CFD model analyzed pure hydrogen operation at 1.4 MWth (100%), 1.0 MWth (71.4%), and 0.7 MWth (50%). Results show that the predicted outlet NO concentration increases from 34 ppm at 1.4 MWth (100%) to 50 ppm at 0.7 MWth (50%), despite reduced high-temperature zones, while the chamber-scale gas inventory time increases during turndown. These results indicate that the proposed multi-stage radial hydrogen injection strategy provides a practical design reference for the development and industrial application of MW-scale hydrogen burners.