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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2018, Vol. 39 ›› Issue (6): 121988-121988.doi: 10.7527/S1000-6893.2018.21988

• Fluid Mechanics and Flight Mechanics • Previous Articles     Next Articles

Influence of pressure oscillation on self-pulsation of gas-liquid swirl coaxial injector

KANG Zhongtao1,2, WANG Zhenguo2, LI Qinglian2, CHENG Peng2   

  1. 1. Science and Technology on Scramjet Laboratory, Hypervelocity Aerodynamics Institute, China Aerodynamics Research and Development Center, Mianyang 621000, China;
    2. Science and Technology on Scramjet Laboratory, National University of Defense Technology, Changsha 410073, China
  • Received:2018-01-03 Revised:2018-03-01 Online:2018-06-15 Published:2018-03-01
  • Supported by:
    Program for New Century Excellent Talents in University (NCET-13-0156); National Natural Science Foundation of China (11472303, 11402298); National Basic Research Program of China (613239)

Abstract: To understand the influence of pressure oscillation on the self-pulsation characteristics of the gas-liquid swirl coaxial injector, non-reactive spray experiments are conducted with water and air at atmospheric pressure. The spray morphology of the pressure swirl injector with and without pressure oscillation is investigated, and that of the gas-liquid swirl coaxial injector with and without the pressure oscillation when self-pulsation occurs is also investigated. The results indicate that the conical liquid film produced by the pressure swirl injector oscillates periodically with the pressure oscillation in the supply system, and the Klystron effect occurs simultaneously. The frequency of the conical liquid film oscillation and the Klystron effect occurrence is consistent with that of pressure oscillation in the supply system. The Klystron effect decreases the spray cone angle, and wrinkles the conical liquid film. The self-pulsated spray morphology of the gas-liquid swirl coaxial injector is also significantly influenced by the pressure oscillation in the supply system. The decrease of the spray cone angle caused by the Klystron effect increases the branches of the Christmas tree and the frequency of self-pulsation. This is because the Klystron effect occurs when the faster liquid film overtake the slower liquid film, which increases the velocity of the liquid film. And the larger the liquid film velocity, the larger the self-pulsation frequency. Although frequency locking does not occur with pressure oscillation, the strength of self-pulsation is decreased to some extent, and one dominant self-pulsation frequency evolves into two domain frequencies.

Key words: pressure oscillation, gas-liquid swirl coaxial injector, self-pulsation, atomization, Klystron effect

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