Unsteady Ejector System Rig

There are two laboratory scale rigs which have been established for the investigation of fundamentally unsteady, air-breathing propulsion systems. Both are located in the Research Combustion Laboratory (RCL) area. This was formerly known, and is still often referred to, as the Rocket Lab. The first, in Test Cell 14, is a small-scale, gasoline or methanol fueled pulsejet engine. The engine was fabricated at GRC, but is an exact copy of a commercially available unit which is used to power hobby-scale model aircraft. While not practical as a stand-alone propulsion system, it is reliable, self-aspirating, versatile, and inexpensive to manufacture and operate, making it ideal for fundamental investigations related to unsteady, impulsive propulsion. The test cell which houses the pulsejet can be configured in several ways, depending on the phenomenon of interest. A suite of instruments is available to measure standard engine operational parameters such as mass flow rate, pressure (dynamic, and mean), temperature, and thrust.

The second rig, located in Test Cell 31, is a Pulse Detonation Engine (PDE). Again, the scale is quite small (only about 1 lbf. of thrust), hence the official name: Small Detonation Facility. The test cell is equipped similarly to Cell 14 described above since similar measurements are made. However, a PDE is a more complex device from an operational standpoint. It requires high speed valving, precise fuel and oxidizer metering, and a spark source, all coordinated in a prescribed manner. As such, the facility is more highly instrumented and has a relatively sophisticated control room. Furthermore, the PDE runs off of pressurized hydrogen or ethylene, and pressurized air. Such components necessitate higher levels of control due to safety considerations.

Both rigs have been used extensively to investigate unsteady ejector systems, plume dynamics of impulsive propulsion systems, pressure-gain combustion systems, and the fluid dynamics associated with deflagrative and detonative combustion.

Publications

John, Wentworth T., Paxson, D. E., and Wernet, Mark P., "Conditionally Sampled Pulsejet Driven Ejector Flow Field Using DPIV,” AIAA paper 2002-3231, June, 2002.

Opalski, A. B., Paxson, D. E., and Wernet, M. P., " Detonation Driven Ejector Exhaust Flow Characterization Using Planar DPIV," AIAA paper 2005-4379, July, 2005.

Paxson, D. E., Dougherty, K.,"Ejector Enhanced Pulsejet Based Pressure Gain Combustors: An Old Idea With A New Twist, " AIAA paper 2005-4216, July, 2005.

Paxson, D. E., Wilson, J., and Dougherty, K.," Unsteady Ejector Performance: An Experimental Investigation Using a Pulsejet Driver, " AIAA paper 2002-3915, July, 2002.

Wilson, J. and Paxson, D. E., " Unsteady Ejector Performance: An Experimental Investigation Using A Resonance Tube Driver, " AIAA paper 2002-3632, July, 2002.

Wilson, J., Sgondea, A., Paxson, D. E., Rosenthal, B. N. " Parametric Investigation of Thrust Augmentation by Ejectors on a Pulsed Detonation Tube, " AIAA Journal of Propulsion and Power, Vol. 23, No. 1, Jan.-Feb. 2007, pp. 108-115, also AIAA paper 2005-4208, July, 2005.

Paxson, D. E., Wernet, M. P. John, W. T., "An Experimental Investigation of Unsteady Thrust Augmentation Using a Speaker-Driven Jet," AIAA Journal, Vol. 45, No. 3, March, 2007, pp. 607-615, also AIAA paper 2004–0092, January, 2004.

Wilson, J., Wernet, M. P., Paxson, D. E., "Vortex rings in a Shrouded Hartmann-Sprenger Tube, " AIAA Journal, Vol. 44, No. 11, Nov. 2006, pp. 2706-2719.

Contact

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last updated: 2.29.08