Atlas Vernier Engine Firing while Supplied with Fuel from Pistonless Rocket Pump

We ran the pump with a rocket engine on Friday 5-23-03 near Mojave at the Reaction Research Society MTA. The pump worked very well, providing a steady flow at high pressure. The engine had problems, however, causing it to use excessive fuel.

You can also see a video of the pump in operation.

The pump ran for about 27 seconds, pumping fuel at 350-400 psi and 20 GPM into the rocket engine. During the first few seconds of the test, the fuel flow rate nearly doubled, due to a combination of a breached O ring or a hole in the cooling jacket. We were using an engine that had been through an explosion and a high velocity impact. So the engine was somewhat suspect before the test. We are a self funded operation, so we could not afford to test with a less abused surplus engine.

The pump is inside the black fuel tank. The tank runs at 50 psi of internal pressure and the pump brings the pressure up to 400 psi to run the test stand in the background.

We tested the pistonless rocket pump with an 1000 lbf thrust Atlas Vernier LR-101 LOX/Kerosene rocket engine on Friday May 23rd at the Reaction Research Society Mojave Test Area. The pump was pumping kerosene, while the liquid oxygen was pressure fed. (we have used the pump for Liquid Nitrogen, so we will be using it to pump LOX in a future test, see www.rocketfuelpump.com)

^ The graph above shows the fuel pressure and flow rate during the test. The fuel leak caused an excessive flowrate, about 24 GPM instead of 14 GPM nominal. This caused the engine to run out of fuel during the test, which resulted in excessive flow and pressure fluctuations. Due to the dual chamber nature of the pump, one chamber ran out of fuel first and caused a drop in fuel flow. The other chamber then took over, causing the fuel flow to increase. The flow trace appears to indicate increased flow when the pressure decreses, but this is due to helium in the fuel line, which flows faster than the fuel. The steps in the flow rate graph are caused by a slow responding turbine flow transducer.

Contrast the benign failure of the pistonless pump with a turbopump, in which case fuel starvation would probably cause the pump to explode as it sped up due to cavitation on the pump side.

A paper on the pump that I presented at the Responsive space conference is available. A Powerpoint presentation that I gave at the California Space Institute is also available.

The pistonless pump is 90% less expensive than a turbopump, at comparable weight. It is also more intrinsically safe and reliable than a turbopump. It offers substantial weight savings over a pressure fed system with a minimal increase in complexity.

Many thanks to Dave Crissali of the RRS, who let us use the facility.

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