From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-x535.google.com (mail-pg1-x535.google.com [IPv6:2607:f8b0:4864:20::535]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 12C0A3CB38 for ; Wed, 26 Apr 2023 17:05:04 -0400 (EDT) Received: by mail-pg1-x535.google.com with SMTP id 41be03b00d2f7-518d325b8a2so7536928a12.0 for ; Wed, 26 Apr 2023 14:05:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ieee.org; s=google; t=1682543103; x=1685135103; h=references:to:cc:in-reply-to:date:subject:mime-version:message-id :from:from:to:cc:subject:date:message-id:reply-to; bh=idUOVERSAXNDJG7VRGb4tgtQz4fKetwjCMyZKb4qolc=; b=GkViVcY1Dvei/Hxv98p+dTY07rI1NGVX87ql8vbglf2UkCgfyuxfxzWzRta9nyZT5l hQOLhiQbv3jKIIXpdswjvDCm6iilIAfMj+alyQr2OGsMb7nyhcx0bz6EEiXcRcGqvl1L ztemfrDSrr+gVAI67DSeAC1NJytkPOcCqBdKM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1682543103; x=1685135103; h=references:to:cc:in-reply-to:date:subject:mime-version:message-id :from:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=idUOVERSAXNDJG7VRGb4tgtQz4fKetwjCMyZKb4qolc=; b=gZxKc7ah/uliC/tpob/mSJ0uElc1I1xEDHnABDzABZwOUM4SKcByMtYa14Dumm7QrC OMT0BwEprFaOujbSnrPnnwHB8bSioSxRgxwGbKToxqkTwGrzkEtW4VRGtl1IAfBejwUx CRWKQWcCFSeXn1H0GbiU0Z/8bIPItZ7Y4LUJhkddrCJqPpvCLYLg+0ByFRpQuqE10LC6 Bg5w6TTo30PfEbXw/YozfuAgnofHI/cRLPeorsj0TU0LIFa/lX1DtTquLvUgU341KD/c PntmF2RorOei9wp4bqX2XU8efkdMtBHIrKI7b+1TmP7lKg2rrO1Idb5SLUCiaTeFaw2S 3XtA== X-Gm-Message-State: AAQBX9c8YAVFpd9+knJGGtN6tKc+Vl2psjIgMWLg+1sEyAIEwSPXBw2H zyWenRYipvECFgZvWUJPp3UUNg== X-Google-Smtp-Source: AKy350YZCauOWe6dsRYQ1fyUEpd7cdQ74nXMLbXumNAY8vs7zCYhay1mYSNZTNgD2KGCcZdn8blGKA== X-Received: by 2002:a17:902:ceca:b0:19e:665b:2514 with SMTP id d10-20020a170902ceca00b0019e665b2514mr30540847plg.43.1682543103022; Wed, 26 Apr 2023 14:05:03 -0700 (PDT) Received: from smtpclient.apple (dhcp-72-253-196-65.hawaiiantel.net. [72.253.196.65]) by smtp.gmail.com with ESMTPSA id h11-20020a170902748b00b001a641e4738asm10368087pll.1.2023.04.26.14.05.01 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 26 Apr 2023 14:05:02 -0700 (PDT) From: Eugene Y Chang Message-Id: <1F70FD46-3CC0-47D5-9691-CE3FBA58F34A@ieee.org> Content-Type: multipart/signed; boundary="Apple-Mail=_58887A0F-CCC7-483B-9F7A-3091D4C9E9E9"; protocol="application/pgp-signature"; micalg=pgp-sha256 Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3696.120.41.1.3\)) Date: Wed, 26 Apr 2023 11:05:00 -1000 In-Reply-To: <202304262041.33QKfOVh096953@gndrsh.dnsmgr.net> Cc: Eugene Chang , Dave Taht , Dave Taht via Starlink To: "Rodney W. Grimes" References: <202304262041.33QKfOVh096953@gndrsh.dnsmgr.net> X-Mailer: Apple Mail (2.3696.120.41.1.3) Subject: Re: [Starlink] some post Starship launch thoughts X-BeenThere: starlink@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: "Starlink has bufferbloat. Bad." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 26 Apr 2023 21:05:04 -0000 --Apple-Mail=_58887A0F-CCC7-483B-9F7A-3091D4C9E9E9 Content-Type: multipart/alternative; boundary="Apple-Mail=_D5065A55-256D-4FA3-9D2C-D4A8A8096CDB" --Apple-Mail=_D5065A55-256D-4FA3-9D2C-D4A8A8096CDB Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Rodney, I agree with your point of view. To neutralize the exhaust of the rocket engine, it is all about taking = the energy out of the exhaust. Taking out the energy will slow the speed = of the exhaust gas and take down the temperature. To get into more nitty gritty, the amount of heat absorbed by H2O or = LN2, depends on the dT (the temperature change) and also any heat of = phase transition (e.g. liquid to gas). Gene ---------------------------------------------- Eugene Chang eugene.chang@ieee.org o 781-799-0233 > On Apr 26, 2023, at 10:41 AM, Rodney W. Grimes via Starlink = wrote: >=20 >> As always I enjoy the flood of information we get on this list! >>=20 >> still, so far, my research on a nitrogen deluge system (instead of >> water) has come up empty for me, except as a fire suppressant. So = it?s >> either crazy or brilliant. Or both! I really liked the idea of >> something cooler that was a natural byproduct of the LOX process... >=20 > I dont think cooler does much, isnt it the "energy of vaporization" > that is actually doing all the "work" in this type of system? >=20 > H2O is 40.7 kJ/mol and LN2 is 5.6 kJ/mol so you would > need ~7 times as much LN2 to do the same work. >=20 > And the reason N2 is used as a fire suppressant is again not > because of temperature, but because it displaces the O2 and > suffocates the fire. N2 is also easier on our ozone layer > than the prior used Halon. Finally, this is usually > compressed N2 gas, not LN2. >=20 > -- > Rod Grimes = rgrimes@freebsd.org > _______________________________________________ > Starlink mailing list > Starlink@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/starlink --Apple-Mail=_D5065A55-256D-4FA3-9D2C-D4A8A8096CDB Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=us-ascii Rodney, 
I agree with your point of = view.

To = neutralize the exhaust of the rocket engine, it is all about taking the = energy out of the exhaust. Taking out the energy will slow the speed of = the exhaust gas and take down the temperature. 

To get into more nitty = gritty, the amount of heat absorbed by H2O or LN2, depends on the dT = (the temperature change) and also any heat of phase transition (e.g. = liquid to gas).
Gene
-------------------------------------------= ---
Eugene Chang
eugene.chang@ieee.org
o 781-799-0233




On Apr 26, 2023, at 10:41 AM, Rodney W. Grimes via Starlink = <starlink@lists.bufferbloat.net> wrote:

As always I enjoy the = flood of information we get on this list!

still, so far, my research on a nitrogen deluge system = (instead of
water) has come up empty for me, except as a = fire suppressant. So it?s
either crazy or brilliant. Or = both! I really liked the idea of
something cooler that was = a natural byproduct of the LOX process...

I dont think cooler does much, isnt it the "energy of = vaporization"
that is actually doing all the "work" in = this type of system?

H2O is 40.7 kJ/mol and = LN2 is 5.6 kJ/mol so you would
need ~7 times as much LN2 = to do the same work.

And the reason N2 is = used as a fire suppressant is again not
because of = temperature, but because it displaces the O2 and
suffocates = the fire.  N2 is also easier on our ozone layer
than = the prior used Halon.  Finally, this is usually
compressed N2 gas, not LN2.

--
Rod Grimes =             &n= bsp;           &nbs= p;            =            rgrimes@freebsd.org
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Starlink mailing list
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https://lists.bufferbloat.net/listinfo/starlink

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