Method and device for modulation of a flame

    公开(公告)号:US06640549B1

    公开(公告)日:2003-11-04

    申请号:US10421186

    申请日:2003-04-24

    IPC分类号: F02C500

    摘要: This invention relates to air breathing engines, such as ramjets, scramjets and internal combustion, and more particularly to an active combustion control device for a combustor. In more particularity, the present invention relates to a method and apparatus that applies active combustion control technology to advanced propulsion devices and closed-loop fuel injection at sub-harmonic frequencies of the instability frequency of the combustor. The problem of limited actuator frequency response is addressed by injecting fuel pulses at sub-harmonic frequencies of the instability. The fuel may be liquid, solid or gas. To achieve this desired result, a closed loop controller is designed to determine sub-harmonic frequencies using a divider to divide the instability frequency of a combustor, yielding a fraction of the harmonic frequency. Also, this invention also combines open loop injection control with closed loop injection control to obtain enhanced engine performance, which includes extension of the stable combustion zone.

    Enhancement of flow mixing by a frequency tunable cavity
    4.
    发明授权
    Enhancement of flow mixing by a frequency tunable cavity 失效
    通过频率可调谐腔增强流动混合

    公开(公告)号:US5520459A

    公开(公告)日:1996-05-28

    申请号:US273031

    申请日:1994-06-30

    摘要: A shear layer of a fluid flow has relatively large vortical structures generated by acoustic forcing from oscillations induced in a cavity closely adjacent to the flow so that these structures enhance mixing at the layer. The forcing frequency is selected by varying the dimensions of the cavity, and several cavities of different dimensions may be provided for forcing at different frequencies, including beat frequencies. The cavity provides passive, high amplitude forcing effective with a compressible shear layer due to high speed flow, including supersonic flow. Cavities of differing configuration provide forcing for fluid flow from nozzles of different geometries. The most effective enhancement is provided by particular excitation frequencies generated by a cavity having a size selected in accordance with dimensionless relations between the flow parameters and nozzle geometry.

    摘要翻译: 流体流动的剪切层具有相对较大的涡旋结构,该声学结构通过从与流体紧密相邻的空腔中诱发的振荡的声学强迫产生,使得这些结构增强了该层的混合。 通过改变空腔的尺寸来选择强制频率,并且可以提供不同尺寸的多个空腔用于在包括拍频的不同频率下强制。 空腔由于高速流动(包括超音速流动)而具有有效的可压缩剪切层的被动,高振幅强制。 不同结构的腔体提供强制流体从不同几何形状的喷嘴流出。 最有效的增强由具有根据流量参数和喷嘴几何形状之间的无量纲关系选择的尺寸的空腔产生的特定激发频率提供。