In my mind a rocket engine would be much more tolerant of debris since you just pipe the fuel into a giant fireball (yes I can practically see the eyes rolling, sorry! :-). For ICEs I can understand clogging tiny injectors or carbs would be a problem, do rocket engines also have injectors or other narrow parts susceptible to clogs?
Yes[1]. You want the fuel and oxidizer mixed as well as possible to achieve efficient combustion.
There are also other small channels fuel has to flow through, like the ones used for regenerative cooling[2].
And not sure how well most turbopumps[3] would tolerate debris either, though that probably depends on the exact design.
There are some really simple rocket designs out there that I could imagine tolerating debris (like solid motors[4] or pressure fed hyperbolic engines[5]) but Raptor definitely doesn't fall into those categories.
I posted upthread, but another concern is that stray particulate is an ignition source. Rocket fuel pumps are ~100,000 hp, and that energy is put into kinetic energy of the fluid flow. A stray particulate can cause the metal pump and fuel lines to burn in the presence of O2 at 300 atmospheres.
Fuel pumps are one of the most important design considerations of a rocket. When people talk about a rocket's specs, it's often going to be in the approximate order of thrust, efficiency (called ISP), fuel, and then what kind of fuel pump it has, aka its cycle
yeah copper burns green and is commonly used in liners and other components. If it starts to burn, which it's not suppose to, you see green. You'll see a green flash when the merlin engines startup but that's because of the hypergolic fluids used to get the pumps running and ignition started, not copper burning. During Falcon night launches you can really see the green glow of the starter fluid on ignition.
Yes, they do. All of the fuel and oxidizer goes through injectors to atomize it as it is sprayed into the combustion chamber. For a Merlin 1D, that’s about 340 pounds of propellant going through the injector plate every second.
The problem is that that fuel gets routed through a thin tube around the engine bell and then goes through a turbo pump before going into the engine. Both of those would have tight tolerances.
The thing is the energy density, flow rate/volume, and heat flux in a raptor is just so extreme. For example, there's two turbopumps operating at around 100k HP each in a volume not much bigger than the propane tank on your grill.. and those are basically just fuel pumps, not even where the real party is (pre-burners and combustion). Anything not going according to plan like a very small piece of debris in a filter causing turbulence or a change in flow rate is almost always catastrophic.
