Testing Phase Preparation (12/10/21)
Testing Phase Preparation
A rocket engine needs to be tested in many different ways before it is cleared to fly. I will be pressure testing my engine and hydrotesting my tanks, then characterizing my venturis and following that plumb my whole system in testing configuration, cold flow and then static fire. Once I static fire I am cleared to build the rocket in flight configuration and then I can begin launch prep tasks.
My next task is going to be a hydrostatic test for my tanks. There are times in industry when the tanks are burst tested but I do not have the capability to make another tank in any reasonable amount of time or money until I either get my own machine shop or go to college and use the college’s machine shop to make all sorts of colorful components for my rockets. In my current case I will test my tanks to a certain safety factor over the system operating specifically not bursting them. Then once I do that, I can begin working towards a water flow test. A water flow test is to characterize the injector, the pressure drop and the DAQ system as well. It pretty much is running the engine on water without ignition. This is just to test out the plumbing, and to test all of the systems without propellant. Once I do that then I can go and cold flow, which is the same thing but with propellants. Then once that is done I can static fire. This will all take several weeks and will be quite an intense process but will be very fun. I can’t make any promises but I hope to have the static fire before the end of the third quarter.
My Data acquisition system is going to be really just a series of pressure transducers and a thermocouple to measure the temperature of the liquid oxygen as it enters the venturis. The venturis will be snug in the main propellant lines, giving a pressure drop but also serving many different purposes, most of which are good. The venturis must be characterized and polished to as high of a discharge rate as possible for a given set of conditions derived from Bernoulli’s law.
NASA SP-194 (1972). Liquid Propellant Rocket Combustion Instability
RPE George Sutton 1984.
Unreasonable Rocket Blog. (2009) Paul Breed