Dynamics Of Adaptive Monitor Head Of Fire Water Monitor

Monitor head is a vital component for fire water monitor and it determines the way to put out the fire and influences the quality of performance.Normal monitor head with a fixed degree of nozzle opening has several defects such as small flow and low efficiency.An adaptive monitor head which adopts the adaptive mechanism has a varying degree of nozzle opening,which makes its degree of nozzle opening change appropriately with the changing flow rate and pressure.Therefore the jet performance,such as range and height,is improved.Due to its advantages of wild flow range,long jet distance and high work efficiency,the adaptive monitor head has been extensively investigated by manufactures and scientists in the relevant fields.The fluid pulsation and other factors in the water pump will lead to a dynamic degree of nozzle opening,which can affect the jet performance.Especially when the excitation frequency reaches the inherent frequency of monitor head,the fire water monitor or the cantilever crane where the fire water monitor is installed will severely vibrate,making the jet separate so that the fire rescue can't finish in time.Therefore,the dynamics of adaptive fire water monitor is to investigate the effects of its design parameters on the variates such as inherent frequency and vibration amplitude,which is of great importance to improve the system operating stability and optimize the jet performance.Investigation on bulk elastic modulus of air and liquid mixing fluid.On the basis of Henry's Laws,the evolution of cavitation inside the monitor head is analyzed and the dynamic characteristics of free and dissolved gas in the fluid are considered,the change laws of gas phase are expressed by the quintic polynomials and then the bulk elastic modulus of air and liquid mixing fluid is constructed by the theoretical model.Then the model is verified by the authorized theoretical models and the experimental data in the sample.The effects of fluid pressure and initial air content on the fluid stiffness and density are analyzed,which provides supports to dynamic analysis and parameter optimization.Free vibration analysis on adaptive fire water monitor head system.The dynamic model and equations of the adaptive fire water system are established.The modal analysis on the system is conducted by the analytical method.The inherent frequency and modal shape of the transverse vibration of the system under different initial gas contents and fluid pressure are discussed.The formula derivations for the sensitivity of the modal natural frequency to each design parameter are obtained.Forced vibration analysis on adaptive fire water monitor head.The equations of the forced vibration of the adaptive fire water monitor is obtained,and the vibration response to the system within the time and frequency domain is solved respectively.The effects of design parameters on the vibration response within the frequency domain is analyzed.Parametric vibration analysis on adaptive fire water monitor head.Due to the periodic fluctuation of the fluid pressure pulsation,the equivalent model of the fluid stiffness is obtained.The formulas of the parametric vibration is derived.The main resonance response is solved when the excitation frequency is close to the inherent frequency.The combined resonance response when the excitation frequency is close to the combined frequency and the fluid stiffness fluctuation frequency is obtained respectively.Dynamics experiment on adaptive fire water monitor head.The design of the jet platform for the adaptive fire water motor is completed,and then the platform is constructed to conduct the experiment.The obtained results are of great value to be as references to analyze the frequency components of fire water monitor.