| With the continuous improvement of intelligence and information level of ammunition fuze in weapon system,there are more and more circuits to meet the function of modern fuze,and the requirements for fuze energy are also higher and higher.The air flow resonant generator used in early fuzes was mostly converted by magnetoelectric energy,which was large and could not meet the power supply demand of modern fuzes for miniaturization and high output.Thus,the airflow induced acoustic piezoelectric generator was created.As a physical power source for fuzes,the design of the airflow induced acoustic piezoelectric generator must meet the tactical technical requirements for fuze power.The airflow induced acoustic piezoelectric generator outputs electrical energy through the piezoelectric energy transfer after the acoustic signal induced by the head-on airflow excitation,which has the advantages of high energy density,small size and reliable structure without moving parts.After the preliminary theory research,the principle prototype is designed.In order to make the airflow induced acoustic piezoelectric generator applied to the fuze as soon as possible,it is necessary to carry out engineering application research to meet the requirements of rapid power generation and power supply on the ballistic path in conjunction with the working environment of the fuze.Due to the fact that the airflow induced acoustic piezoelectric generator use oncoming airflow excitation to generate electricity,the randomness and instability of the oncoming airflow will lead to problems such as the generator not generating electricity,and the output power being unstable or small.Therefore,the stability of the hydrodynamic sound source induced by the oncoming airflow is key to the engineering design.Based on previous research,this paper will further analyze the influencing factors of dynamic excitation of the airflow induced acoustic piezoelectric generator,reasonably design and control the sensitive structural parameters,and mainly solve the key problems of the stability of the hydrodynamic sound source and the maximum power output.This research has important military application value.The fuze circuit requires that the fuze power supply can provide a stable output voltage and supply power continuously.Unstable power supply voltage can easily lead to accidents,affecting the combat performance of weapons and equipment.Therefore,this paper studies the stability of the dynamic excitation of the hydrodynamic acoustic source generated by the oncoming airflow of the acoustic piezoelectric generator caused by the airflow,the accuracy of the frequency estimation of the short resonant cavity and the fast energy response of the fuze power supply.and the multi-parameter influence analysis of the excitation mechanism of the airflow-induced acoustic piezoelectric generator and the analysis of the fast energy storage process of the fuze application are carried out.With mortar shells as the application background,the inlet velocity of the airflow induced acoustic piezoelectric generator was determined to be in the range of 50 m/s～250 m/s,and this velocity was used as the test condition for the static simulation test and dynamic firing test in the laboratory of the test prototype.According to the structural parameters of the excitation mechanism of the airflow-induced acoustic piezoelectric generator,the sensitive parameters affecting the stability of the hydrodynamic sound source are determined through the multi-parameter joint influence analysis.The empirical formula for estimating the acoustic modal frequencies of short resonant cavities is modified,and the conditional expressions for the engineering design of the excitation mechanism are proposed.According to the modified empirical formula for estimating the acoustic mode frequency of the short resonant cavity,the conditional expression for the engineering design of the excitation mechanism is modified twice.The orthogonal test results show that the most sensitive parameter affecting the sound pressure amplitude is the annulus value,followed by the spacing,and the weakest is the length of the resonant cavity.The optimal combination of sound pressure amplitude is:313.The most sensitive factor affecting the sound pressure frequency is the length of the resonant cavity,followed by the annular space,and the spacing has no effect.The optimal combination of the sound pressure frequency is313.The optimal energy storage capacitor selection strategy is proposed,and the fuze circuit suitable for the airflow-induced acoustic piezoelectric generator is improved and designed.Through the analysis of the fast energy conversion circuit of the airflow-induced acoustic piezoelectric generator,the fastest energy storage scheme in different charging cycles is determined,and the selection strategy of the optimal energy storage capacitor under different emission conditions is proposed.According to the characteristics of the airflow-induced acoustic piezoelectric generator and the design defects of the existing fuse circuit,the interface circuit suitable for the aeroacoustic piezoelectric generator is improved and designed.The static simulation in laboratory and the dynamic shooting test in firing range were carried out for the output capability of the airflow-induced acoustic piezoelectric generator.The test results show that:When the laboratory static simulation is more than 15000g and the continuous overload time is more than 1ms,the average instantaneous power output of the airflow-induced acoustic piezoelectric generator is 13.8 m W,and the average energy conversion time is 24.57ms;The dynamic shooting test in the shooting range at 133m/s muzzle velocity projectile,the energy storage capacitor voltage reaches 5.54V,and the instantaneous power 3.49m W,which has basically reached the power supply demand level of fuze application,indicating that the airflow induced piezoelectric generator can generate electricity in the fuze application environment. |
