Studying the effect of increasing the hydrogen content in hydrogen-enriched synthetic gas

In the quest to decrease or eliminate the use of carbon-containing fuels for power generation to address climate change and comply with emissions regulations, hydrogen fuel is widely considered the front-runner. However, technological hurdles currently prevent the use of pure hydrogen.

In the interim, hydrogen-enriched synthetic gas (syngas) is one of the most promising alternatives. While syngas, which is primarily a mixture of CO and H₂, has been studied for decades, Ganti et al. investigate the effect of increasing the hydrogen content in its composition on the resulting flame structure, a previously unexplored research area.

“Typically when a premixed flame thickens, it is in a region that is referred to as the preheat zone,” said author Prashant Khare “However, in this case, we saw flame thickening in the reaction and burn-out zones. This was a surprising insight.”

The team conducted numerical experiments using direct numerical simulations (DNS). DNS can be thought of as a computational counterpart to physical experiments. Physical experiments are limited to measuring a few flow properties at certain spatial and temporal locations. On the other hand, DNS provides the details of all flow properties at every spatiotemporal location in the region of interest.

“We found that the flame thickness of an initially laminar flame that interacts with homogeneous isotropic turbulence increases as time evolves,” said Khare.

The researchers hope this work will improve the turbulence chemistry interaction models in hydrogen-enriched syngas combustion in practical combustor configurations where DNS is impractical.

“The use of DNS has come a long way from even a decade ago, thanks to tremendous improvement in high-performance computing hardware and software technologies,” said Khare.

Source: “Interactions between high hydrogen content syngas-air premixed flames and homogeneous isotropic turbulence: Flame thickening,” by Himakar Ganti, Luis Bravo, and Prashant Khare, Physics of Fluids (2023). The article can be accessed at https://doi.org/10.1063/5.0156537 .

This paper is part of the Hydrogen Flame and Detonation Physics section, learn more here .