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Show through the atomizing stream and also avoid the formation of large recirculation zones characteri s tic of a larger injector. This will also allow continued progress toward optimizing the ratio of propane to CWS, since parallel injection should fully utilize the pulsating flow, and it should be possible to use multiple parallel injectors in a pulse combustor of the current size. Also observed in the photographs is the short duration of effecti ve atomization, generally 4 to 5 ms. If one is to avoid formation of large droplets between pulses this requires pulse frequencies on the order of 100 to 200 hertz. But it must be kept in mind that the high frequency mode with lower amplitudes did not provide good atomization. The need is for high frequency at high pressure amplitude. This avenue is being pursued in current pulse combustion studies at METC, where frequencies as high as 60 hertz have been achieved in the high amplitude mode in which the aerovalve is blocked (Fig. 6). 5. CONCLUSIONS Pulse atomization of CWS has been demonstrated using a propane fired pulse combustor, and the atomized slurry has produced a self sustaining flame in a combustor. This technique has potential applications for combustion processes and for spray drying applications. Photographic studies of the pulse atomization process have revealed at least three mechanisms for the formation of large droplets. These are; recirculation behind the injector, injection of fluid with such momentum that it carries through the atomizing stream intact, and formation of large drops between pulses. |