考虑压力脉动的消防水炮自适应炮头射流系统参数振动研究

消防水炮自适应炮头可根据流体压力和流量变化自动调整炮口开度,从而显著提升其射流性能。考虑自适应炮头射流系统中流体的压力脉动,结合流体体积弹性模量与刚度间的关系,建立基于时变流体刚度的射流系统参数振动动力学模型,采用多尺度法推导脉动激励频率接近射流系统固有频率和固有频率与脉动频率的组合频率时的共振响应公式,分析射流系统的主共振和组合共振响应。结果表明射流系统发生主共振响应时,激励频率占主导成分,且接近一阶固有频率时系统共振幅值最大;射流系统发生组合共振响应时,激励频率与流体刚度波动频率的组合频率对系统响应的影响与流体脉动频率有关;主共振和组合共振将恶化系统的动力学行为。本项研究可为深入探索自适应炮头射流系统的动力学特性,优化不同工况环境下的设计参数提供理论依据。

Research on Parameter Vibration of Adaptive Head Jet System of Fire Water Monitor Considering Pressure Pulsation

The adaptive head of fire water monitor can automatically adjust the muzzle opening according to the change of fluid pressure and flow rate. Therefore, the jet performance of fire water monitor can be significantly improved. Considering the pressure pulsation of the fluid in the adaptive head jet system and combining the relationship between the fluid bulk modulus and the fluid stiffness, the parameter vibration model of adaptive head jet system based on the time-varying fluid stiffness is founded. By the multiscale method, the resonance response formulae of jet system are deduced when the excitation frequency is closed to natural frequencies and the combination frequency of the natural frequency and the pulsation frequency of jet system, and the main resonances and combined resonances of the jet system are analyzed. The results show that when the main resonance response of the jet system occurs, the dominant frequency in resonance responses is the excitation frequency, and the resonance amplitudes of the jet system is largest when it is close to the first-order natural frequency. When the combined resonance response of the jet system occurs, the influence of the combined frequency between the excitation frequency and fluid stiffness fluctuation frequency on the system response is related to the fluid pulsation frequency. The main resonances and combined resonances will seriously deteriorate the dynamics behaviour of adaptive head jet system. This research can provide a theoretical basis for further exploration of the dynamic characteristics of the adaptive head jet system of fire water monitor and optimizing the design parameters under different working conditions.