gardner@uiucuxc.CSO.UIUC.EDU (02/01/86)
The SRB's burn from the bottom up. The position of the flame front should be directly calculatable by NASA. The key question is: Would the flame front be near that joint at that point in the flight. Michael Gardner Computer Services Office - University of Illinois Urbana, Ill, 61801 gardner@uiucuxc
kjm@ut-ngp.UUCP (Ken Montgomery) (02/06/86)
[] > The SRB's burn from the bottom up. The position of the flame front should > be directly calculatable by NASA. The key question is: Would the flame > front be near that joint at that point in the flight. > [Michael Gardner] If I understand correctly, you think that the SRB fuel burns at a surface that is at right angles to the long axis of the SRB. This is not correct. The SRB fuel is pierced all the way down the long axis by a star-shaped hole. Burning occurs on the surface thus formed. Side note: the hole is star-shaped to keep the surface area, and thus the burn rate, relatively constant over the burn time. A cylindrical hole would, as the SRB burned, increase in surface area. -- The above viewpoints are mine. They are unrelated to those of anyone else, including my cat and my employer. Ken Montgomery "Shredder-of-hapless-smurfs" ...!{ihnp4,allegra,seismo!ut-sally}!ut-ngp!kjm [Usenet, when working] kjm@ngp.{ARPA,UTEXAS.EDU} [Old/New Internet; depends on nameserver operation]
andrew@cadomin.UUCP (Andrew Folkins) (02/07/86)
In article <152800004@uiucuxc> gardner@uiucuxc.CSO.UIUC.EDU writes: > >The SRB's burn from the bottom up. The position of the flame front should >be directly calculatable by NASA. The key question is: Would the flame >front be near that joint at that point in the flight. > >Michael Gardner >Computer Services Office - University of Illinois >Urbana, Ill, 61801 gardner@uiucuxc SRB's burn from the entire length of the booster from the inside out. The solid fuel itself insulates the outer skin of the booster from the high temperatures within until the booster is almost burned out. A side note on booster destruct : the news last night showed this occuring through blowing the nose cone and nozzle off and splitting the booster itself lengthwise. However, I have heard frome another source (the net?) that only the nose cone and nozzle are blown off, and the exhaust is shot out the front and back of the booster. Does anyone know which is correct? -- Andrew Folkins ...ihnp4!alberta!andrew "We humans think of ourselves as being rather good at reasoning, but at best we perform about a hundred logical inferences a second. We're talking about future expert systems that will be doing ten million inferences a second. What will it be like to put a hundred years thought in every decision? Knowledge is power." - Edward A. Feigenbaum
brad@dcc1.UUCP (labasst) (02/07/86)
In article <2924@ut-ngp.UUCP> kjm@ut-ngp.UUCP (Ken Montgomery) writes: >> The SRB's burn from the bottom up. The position of the flame front should >> be directly calculatable by NASA. The key question is: Would the flame >> front be near that joint at that point in the flight. >> [Michael Gardner] > >This is not correct. >The SRB fuel is pierced all the way down the long axis by a star-shaped >hole. Burning occurs on the surface thus formed. Side note: the hole is >star-shaped to keep the surface area, and thus the burn rate, relatively >constant over the burn time. A cylindrical hole would, as the SRB burned, >increase in surface area. > >[Ken Montgomery] Ken, you have the right idea but your information isn't completely correct either. I have a copy of a shuttle manual ( missing title page so I can't name the source) which says. The high thrust level during lift-off of the Shuttle results from an 11-point-star propellant configuration in the forward segment. After lift-off, thrust is reduced by the total burnout of the star points (at 62 seconds into flight) to constrain flight dynamic pressure. Thrust then gradually increases because of the design of the burning cavity. When the flame surface of the burning propellant reaches the liner surface, the thrust again starts to decay and continues to decay until burnout (about 10 seconds later). I wish I had the original source for this since it covers all the shuttle systems in easy to read language with just enough detail. Brad Beach ...!gatech!dcc1!brad -- I did my own thing and now I have to undo it. Brad Beach ...!gatech!dcc1!brad <= Funny, this doesn't look like me.
lmc@cisden.UUCP (Lyle McElhaney) (02/08/86)
> The SRB's burn from the bottom up. The position of the flame front should > be directly calculatable by NASA. The key question is: Would the flame > front be near that joint at that point in the flight. No. They burn from a central cavity running the entire length of the SRB from the center outwards radially. The pressures and temperatures would blow any casing apart that was not protected by the unburned fuel. Lyle McElhaney ...hao!cisden!lmc
kenner@acf4.UUCP (Richard Kenner) (02/09/86)
Interesting, it looks like the first appearance of the extra plume seems to have occurred right around the time when the initial star configuration of the SRB propellant is supposed to have completed its burn. Coincidence?
paul@axiom.UUCP (Paul O`Shaughnessy) (02/11/86)
Good try on calculating location of the burnthru, but the SRB's do not burn from the bottom up, but from inside out. That makes the combustion surface much larger and should (!) reduce the chance of burnthru.