Assessment of the Performance of a Pulsejet and Comparison with a Pulsed-Detonation Engine

The performance of a Solar PJ32 pulsejet engine, which is a 1/5-scale model of the Argus V-1 pulsejet engine developed for the Navy in 1951, is evaluated under static conditions and compared with that of a pulsed-detonation engine (PDE) firing at similar inlet and operating conditions. The pulsejet has a fuel-flow operating range of 2.5-4.5 lbm/min, which corresponds to a thrust range of 40 lbf (at lean out) to 102 lbf (at flood out). Thrust is calculated from combustion-chamber pressure histories and agrees with measured thrust within 5-10%. Peak combustion-chamber head pressures range from 8 to 20 psig, while significantly higher pressures (80-120 psig) are attained in PDEs. Airflow at the inlet of the pulsejet is measured and used to calculate specific thrust and equivalence ratio. Specific thrust ranges from 40-100 lbf-s/lbm over the range of fuel flows from lean to rich conditions. A similarly operating PDE has a specific thrust around 120 lbf-s/lbm, making the PDE more efficient in terms of air flow. The pulsejet equivalence ratio ranges from 0.6-1.0, with rated/peak thrust occurring at rich conditions. Typical fuel-specific impulse (Isp) for the pulsejet is 1400-1500 s for rated thrust conditions, whereas PDE performance (with a fill fraction of 1) is around 1800 s. For the PDE operating in the same fill fraction range as the pulsejet (~0.1), PDE Isp is estimated to be 6000-8000 s making the PDE cycle far more efficient and desirable at comparable conditions.