Currently, adopting hydrogen as a major fuel carrier is a viable option here in the United States as well as abroad. There are several challenges that must be overcome, though.  One such challenge is hydrogen’s unusual fire hazards.  LACER is investigating how to advance our understanding of the risks of using hydrogen.  We propose that our experiments will result in the improvement of codes and standards for hydrogen vehicles and other hydrogen systems.  

 

Because of hydrogen’s wide flammability limits, nominally 4 – 75% mole fraction in air, it is especially prone to ignition over other gases. Additionally, small hydrogen flames give off nearly no light.  Prior research has shown that hydrogen leaks support combustion at lower flow rates than for other gaseous fuels.  A consequence of these facts is that a small hydrogen leak could ignite and remain undetected for a considerable amount of time. Heating combined with the possibility of material degradation is a distinct possibility with such a flame. This could potentially result in catastrophic consequences such as detonation or a BLEVE (boiling liquid expanding vapor explosions). This scenario is not unique to hydrogen, but it is significantly more probable because of the wide flammability limits.  

 

Our current research is testing and analyzing the flammability limits of hydrogen.  This testing involves hydrogen passing through cracks and leaks of different sizes and shapes.  We propose that with the results of our research, we will be able to predict if ignition is possible knowing the pressure drop, crack size and shape of a particular leak.

 

In addition, we plan to investigate the effects of material degradation. We aim to understand how an undetected flame can affect the storage vessel or pipe from which hydrogen is issuing.  We also seek to understand if a flame will cause such a leak to increase in size.