@nimbostratusYou are not supposed to read the attached file but load it into the software I provided link for Chamber temperature is connected to chamber pressure. RD-170 Pc is very high, therefore the Tc is high too. IIRC only RD-180 has higher Pc among kerolox engines, the RPA tool calculates Tc nearly 3900K for it.
While is may have already been addressed somewhere in this thread, I was hoping that someone could educate me on how hypergols are used in the Antares rocket engine of launch vehicle. My question originates from the recent launch failure and the post-event warning for civilians not to enter the area given the remnanats of hypergols, which I presume was something like a hydrazine derivative and/or N2O4. I am aware that the first stage propellants are RP-1 and LOX, and I am aware that the second stage uses solid propellants. So then I thought that maybe the first stage turbopumps are powered by these hypergols. But then I found out that the first stage engines are staged combustion engines. So hypergols wouldn't be involved here, as the gas driving the turbines are generated by using the kerolox propellants in the pre-burner. So where are these hypergols used in this launch vehicle? Is there an APU, conceivably used to provide hydraulic power to what I preseme might by TVC? Please educate me here. Thank you.
Only a small pressure vessel needs to be at high pressure, the propellant tanks themselves can be kept at low pressure. A small tank is filled with propellant from the main propellant tanks at low pressure, then the feed valve is closed, the pressurisation valve is opened, once the pressure has equalised it is closed again and then the discharge valve is opened and just before it's empty, it is closed again, and then the cycle repeats. It's a bit more complicated than that, but that's the general idea.How the pistonless pump operates
I believe the main advantage is that the system will be lighter and more compact as a result.
Instead of two similar pump chambers, it usesone main chamber which supplies fuel for mostof the time and an auxiliary chamber whichsupplies fuel for the rest of the time. The mainchamber is placed inside the tank, and it is filledthrough a number of check valves so that it canbe filled quickly, thereby reducing the size of theauxiliary chamber, which is typically one fourththe size of the main chamber. The optimizeddesign offers a substantial weight savings overthe basic design, in that it uses one primarypumping chamber and one auxiliary chamberinstead of two pumping chambers.
Quote from: mmeijeri on 11/07/2014 09:42 amI believe the main advantage is that the system will be lighter and more compact as a result.Yes.http://www.rocketfuelpump.com/wp-content/uploads/2013/12/RocketPumpJPC2003.pdfQuoteInstead of two similar pump chambers, it usesone main chamber which supplies fuel for mostof the time and an auxiliary chamber whichsupplies fuel for the rest of the time. The mainchamber is placed inside the tank, and it is filledthrough a number of check valves so that it canbe filled quickly, thereby reducing the size of theauxiliary chamber, which is typically one fourththe size of the main chamber. The optimizeddesign offers a substantial weight savings overthe basic design, in that it uses one primarypumping chamber and one auxiliary chamberinstead of two pumping chambers.Wondering if the volume asymmetry also helps with avoiding bad resonances because the valving sort of "gallops" instead of steady cycling.
Would a compressed air / helium powered turbopump be a reasonable alternative to a Flometrics-style pistonless pump?