作動時のパルス燃焼器の音響特性解析(熱工学, 内燃機関, 動力など)

抄録

Acoustic characteristics of a two dimensional valveless pulse combustion systems having various geometrical constructions are first measured and numerically analyzed under the cold and stagnant conditions, and effects of each acoustic element on the overall resonant properties of the pulse combustion systems are clearly estimated and explained. Comparison of the acoustic resonant behavior numerically analyzed with that experimentally measured yields a suitable set of the acoustic parameters for each system construction, such as the damping factor and reflection coefficient. Frequency characteristics of the resonant pressure fluctuation in the combustion chamber are then numerically estimated under a typical pulse combustion condition, by introducing not only the acoustic parameters obtained but also the longitudinal temperature profile measured. It is found that the resonant pressure exhibits a sinusoidal character and retards in phase by about 35 degree after the original pressure oscillation applied, being in good agreement with those measured in the proposed pulse combustor. It is also confirmed that, by applying it to another type of the pulse combustor, the proposed numerical method can clearly predict the variation in the profile of pressure fluctuation with the tailpipe length.