Nitrous/Ethane Fluid System

The VEGAS test stand consisted of a fuel, ox, and nitrogen side. 

The fuel and ox line each contained a filter, pneumatic ball valve for flow control, and orifice to achieve the desired pressure drop. These two main lines also branched off before the pneumatic valve to provide propellants to a torch igniter. 

The nitrogen side consisted of a regulator, check valves to prevent backflow, 3-way piolet solenoids to power the pneumatics, and 2-way solenoids for purge. 

I contacted vendors to source every valve and fluid fittings (NPT, JIC, and Swage). The system started at tank pressures of 500 psi for ox and 385 psi for fuel. Each line pressure needed to drop to a required pre-injector pressure of 235 psi. 

The team strived to minimize pressure drops to accommodate for the varying equilibrium tank pressure based on ambient temperature. Thus, I tried to find valves with high flow coefficients (Cv) at low prices. 

I calculated pressure drops across valves, pipe friction, and bends using the Moody friction factor and resistance coefficient. Ultimately, the fluid end pressure was well above the required pre-injector pressure to account for variations. The desired pre-injector pressure could then be achieved via pressure drops through orifices.

To route the fluid lines, the team used Solidworks piping and tubing features and followed the symmetry of our P&ID. Although not present in the CAD, every connection and fitting was considered. 

We also employed an aluminum sheet to create surfaces for fluid components and 3D-printed mounts. The system's simplicity avoided drastic pipe bending and only required us to practice cutting and flaring.