Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: SymeAaro on 29/04/2018 18:30:26
-
God I’ve done a lot of rocket stuff.
Anyway, I’ve been doing a bit of looking on the internet, and I think I understand that ISP = Thrust/fuel weight flow rate. I know that the SSMEs have a thrust of 480,000 lbf at SL. I can’t remember their ISP (a quick Wikipedia will do the trick I’m sure), but since I’m a little confused about the units, could someone please use this info to tell me how many kilos (or any other unit of mass) of propellant an SSME (at max thrust) burns per second? Cheers.
-
https://www.google.co.uk/search?q=what+is+the+fuel+consumption+of+the+SSME%3F&oq=what+is+the+fuel+consumption+of+the+SSME%3F&aqs=chrome..69i57j69i60.22780j1j1&sourceid=chrome&ie=UTF-8
Fuel Consumption: 1,340 L per sec (350 gal)
You may have seen this already, but if not, does it help?
-
Wikipedia says sea level Isp is 366 seconds, so to get the propellant flow you just divide that into the sea level thrust of 480,000 lbs to give 1310 lb (mass)/sec.
The fact that that's nearly the same numerical value as the volume is largely accidental; the density of the propellant is the average of the liquid oxygen and the liquid hydrogen.
I'm assuming you're really asking about all of the propellant, but if you really mean fuel, then you'll have to find out how much of the propellant is hydrogen.