Rocket Kart 2.0

 

Why the Change!?

The following changes resulted in a large test stand redesign:

• No longer able to test at FAR
• Need to make a mobile test stand
• Stand was over budget, need cost reduction of a few thousand dollars

The new design is built around a 275 gallon IBC tote. On test day the tote will be transported to the test site with all of its fluid components already attached. The outer steel frame that takes the load of the engine will be placed under the tote and then the tote will be filled with water to hold everything in place. This design is nice because we don't have to make any modifications to the environment we're testing in and everything can be moved in a U-Haul truck and carried by two or three people. 

The P&ID

Things to note:

• Nitrogen purge valves replaced with solenoids
• Regulators replaced with orifices
• Small bypass regulator for leak checks
• Fewer relief mechanisms
• Thinner propellant and nitrogen lines

After remaking my fluids calculator in MATLAB, I found that we could downsize our lines and still meet our flow requirements both on our propellant and nitrogen side. Have a solenoid valve with a Cv = 0.02 only resulted in a 10 psi pressure drop, hence the change depicted upstream of the orifices. These orifices were sized to replenish the space in the propellant tanks as it gets consumed by the engine. Below shows the flow rate required and varying orifice sizes as the pressure in the nitrogen tanks depletes. 

It should also be noted that, while I did get rid of the redundant burst disc, the tank's relief devices are still sized per API 521 fire standards. Additionally, the vents on each tank are normally open. 

Going Forward

This stand is more mobile, designed more closely to the engine's requirements and is cheaper. Construction will begin this year.