Personally, I'm a little in awe of the fact that they created a successful design that runs oxygen rich combustion products from the preburner through the turbopump. High temperature, high pressure, nearly pure oxygen is an incredibly corrosive fluid - you can burn steel that way. I don't mean melting steel, but actually chemically combusting it.
Quote from: iamlucky13 on 10/28/2011 07:43 pm Personally, I'm a little in awe of the fact that they created a successful design that runs oxygen rich combustion products from the preburner through the turbopump. High temperature, high pressure, nearly pure oxygen is an incredibly corrosive fluid - you can burn steel that way. I don't mean melting steel, but actually chemically combusting it.*pst* it's not oxygen-rich.
Quote from: Downix on 10/28/2011 08:13 pmQuote from: iamlucky13 on 10/28/2011 07:43 pm Personally, I'm a little in awe of the fact that they created a successful design that runs oxygen rich combustion products from the preburner through the turbopump. High temperature, high pressure, nearly pure oxygen is an incredibly corrosive fluid - you can burn steel that way. I don't mean melting steel, but actually chemically combusting it.*pst* it's not oxygen-rich.By "they" I'm guessing he means the Russians.. not SpaceX?
I think it might make sense to do that with four AJ-500 engines. But not with the Merlin 1. First, it's not big enough. Just compare the 667kN of the 1D, against the around 2MN of the AJ-500.Second, as has been stated, the Merlin is not a very efficient engine. I personally think they are going to replace it with something new.And third, the problem is not only the combustion chamber for deep throttling, but also the turbopump. So, it would still complicate the landing of a Returnable Falcon 9.
The Soviets only started doing multiple combustion chambers because they had problems with larger combustion chambers. But the recent trend for the Russians has been fewer combustion chambers. See the RD-170 (4) -> RD-180 (2) -> RD-191 (1) evolution of the same engine family.With modern experience and computational tools, I don't think larger combustion chambers are as much of a problem as it has been. That path is a dead end, IMO.
Quote from: Lars_J on 10/28/2011 09:26 pmThe Soviets only started doing multiple combustion chambers because they had problems with larger combustion chambers. But the recent trend for the Russians has been fewer combustion chambers. See the RD-170 (4) -> RD-180 (2) -> RD-191 (1) evolution of the same engine family.With modern experience and computational tools, I don't think larger combustion chambers are as much of a problem as it has been. That path is a dead end, IMO.Even with the most excellent computational fluid dynamics simulations I haven't seen proof that stable combustion can be achieved in arbitrarily large combustion chambers. Has anyone?
Quote from: Lars_J on 10/28/2011 09:26 pmBut the recent trend for the Russians has been fewer combustion chambers. See the RD-170 (4) -> RD-180 (2) -> RD-191 (1) evolution of the same engine family.Not true, each of those engines have equivilent reduction (1/2) in thrust also.
But the recent trend for the Russians has been fewer combustion chambers. See the RD-170 (4) -> RD-180 (2) -> RD-191 (1) evolution of the same engine family.
We know the F-1 worked.
The premise of this thread was more about the economic and technical feasibility of developing a larger engine why maximizing commonality with existing hardware and current possible uses.
I agree a rocket turbopump is no simple matter (especially the art pieces they call turbopumps SpaceX uses).