Comment on World’s first crewed liquid hydrogen plane takes off

• photonic_sorcerer@lemmy.dbzer0.com ⁨1⁩ ⁨year⁩ ago

  Well you know what else is explosive? Jet fuel!

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  • A_A@lemmy.world ⁨1⁩ ⁨year⁩ ago

    Do you know how brittle metals become at very low temperature ? Did you notice I did not talk about hydrogen explosiveness ?

    But sure, let’s now talk about explosiveness. Do you know the mixture ratio range is completely different (much greater) for air + H^2^ explosive mixture as compared to other mixtures ? You are very far from an expert on the topic aren’t you ?

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    • Cleverdawny@lemm.ee ⁨1⁩ ⁨year⁩ ago

      Hydrogen isn’t explosive, it’s flammable. Just like jet fuel.

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      • A_A@lemmy.world ⁨1⁩ ⁨year⁩ ago

        Detonation
        “A very wide variety of fuels may occur as gases (e.g. hydrogen), droplet fogs, or dust suspensions. In addition to dioxygen, oxidants can include halogen compounds, ozone, hydrogen peroxide, and oxides of nitrogen. Gaseous detonations are often associated with a mixture of fuel and oxidant in a composition somewhat below conventional flammability ratios.”

        For Hydrogen, if I recall correctly, the explosive range is from 4% to 75% hydrogen in air. I may dig a little bit more to find sources.

        How many more false experts want to comment on this ? And feel free to downvote, you only underline your ignorance and arrogance.

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• PrincessLeiasCat@sh.itjust.works ⁨1⁩ ⁨year⁩ ago

  It also had 5 pressure vessels’ worth of liquid H2 for the fuel cells in the payload bay (and never had any issues wrt that, though of course it did present its own challenges). Challenger’s “failure mode” was in the SRB. The ET happened to be right next to it. We can talk about the ET and its direct impact on Columbia because the foam shedding was a problem with the ET. And of course, the issues with the NASA culture that were present for both.

  I’m not going to wade into the semantics of explosive vs flammable argument further down because at the end of the day it’s semantics.

  And I am an expert since you seem very intent on only experts partaking in this discussion.

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  • A_A@lemmy.world ⁨1⁩ ⁨year⁩ ago

    I agree the SRB was the start of the huge explosion that somehow involved liquid hydrogen. I was posting that example because I was replying to an example where it was gaseous hydrogen combustion and because for the plane in the post it is liquid hydrogen which is used.

    I don’t mind talking to non-expert as long as they don’t believe they know what they don’t know and do not insist they know better when they don’t.

    From your comment I don’t know what “ET” means but I suppose “SRB” is something like side booster rocket (?) I am not an expert of the space shuttle so please tell me if it pleases you to do so.

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    • PrincessLeiasCat@sh.itjust.works ⁨1⁩ ⁨year⁩ ago

      ET is the External Tank, the orange part of the Shuttle that held liquid H2 and O2.

      The gaseous H2 was still a concern for the H2 tanks in the Payload Bay. If there was a leak that accumulated H2 in the bay after the Payload Bay doors were closed for re-entry, that would be a flammability concern.

      They both present their own sets of problems and failure modes that need to be discussed and mitigated, but we do have experience in other areas to look back on and learn from.

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      • A_A@lemmy.world ⁨1⁩ ⁨year⁩ ago

        I want to apologize for posting that explosion image if maybe you were working on the space shuttle or close to people in there.

        Many years ago I came to know an industry where accidental hydrogen explosions were to be described as “rapid oxidation events” (ROE) for insurance paperwork. Somehow writing the word “explosion” would have made insurance costs explode !
        There are strong (& more) reasons to disbelive commercial transport projects involving hydrogen as energy source (energy vector).

        Thanks for your time and explanations.

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