火箭推进

针对真空环境中压电激励液滴生成技术,采用实验方法研究了压电激励波形、频率和位移等参数对射流破碎特性的影响规律。实验结果表明,对0.5 mm的射流在理论最优频率下施加振幅3 μm的压电激励作用后,射流破碎距离缩短至90 mm左右; 相对于正弦波与三角波,方波激励获得的射流破碎距离最短; 在最优频率附近,随着激励频率增大,液滴粒径减小,射流破碎长度先减小后增大; 随着压电装置位移幅值增大,射流破碎长度略有减小。结果表明:在压电作用下,激励频率对射流特性影响较大,并且射流最短破碎距离对应的激励频率大于理论最优频率; 激励波形和位移振幅等参数对射流破碎特性的影响相对较小。

Aiming at droplet generation technology in vacuum environment,the effects of piezoelectric excitation waveform,frequency and displacement on jet fragmentation were studied by experimental research. The results show that after the piezoelectric excitation of 3 μm is applied to the jet with diameter 0.5 mm at the theoretical optimal frequency,the breaking distance of the jet is shortened to about 90 mm. Compared with the sinusoidal and triangular waves,the jet breaking distance obtained by square wave excitation is the shortest. Near the optimal frequency,with the increase of excitation frequency,droplet diameter decreases,and jet breakup length decreases first and then increases. With the increase of piezoelectric displacement amplitude,jet breakup length decreases slightly. It is found that under the action of piezoelectric force,the excitation frequency has the great influence on jet characteristics,and the frequency corresponding to the shortest breaking distance is larger than the theoretical optimal frequency. The parameters such as excitation waveform and displacement amplitude have relatively small influence on jet breaking characteristics.

引言
1 实验装置及实验方法
2 实验结果与讨论
3 结论

图1 喷射器结构<br/>Fig.1 Droplet generator structure

图1 喷射器结构
Fig.1 Droplet generator structure

图2 压电装置及信号控制系统<br/>Fig.2 Piezoelectric device and signal control system

图2 压电装置及信号控制系统
Fig.2 Piezoelectric device and signal control system

图3 液体真空喷射雾化特性研究试验平台<br/>Fig.3 Liquid vacuum injection test system

图3 液体真空喷射雾化特性研究试验平台
Fig.3 Liquid vacuum injection test system

表1 典型实验工况及结果<br/>Tab.1 Typical test conditions and results

表1 典型实验工况及结果
Tab.1 Typical test conditions and results

图4 压电激励对真空射流状态的影响<br/>Fig.4 The influence of piezoelectric excitation on the vacuum jet shape

图4 压电激励对真空射流状态的影响
Fig.4 The influence of piezoelectric excitation on the vacuum jet shape

图5 在3 kHz激励频率下的喷射器内压力脉动特性<br/>Fig.5 The pressure fluctuation in the injector at 3 kHz excitation frequency

图5 在3 kHz激励频率下的喷射器内压力脉动特性
Fig.5 The pressure fluctuation in the injector at 3 kHz excitation frequency

图6 喷射器内压力脉动幅值随激励频率的变化规律<br/>Fig.6 Variation of pressure fluctuation amplitude with excitation frequency in injector

图6 喷射器内压力脉动幅值随激励频率的变化规律
Fig.6 Variation of pressure fluctuation amplitude with excitation frequency in injector

图7 不同激励波形下的射流形态对比<br/>Fig.7 Jet shape corresponding to excitation waveform

图7 不同激励波形下的射流形态对比
Fig.7 Jet shape corresponding to excitation waveform

图8 激励波形对应的脉动压力幅值<br/>Fig.8 Amplitude of fluctuating pressure corresponding to excitation waveform

图8 激励波形对应的脉动压力幅值
Fig.8 Amplitude of fluctuating pressure corresponding to excitation waveform

图9 扰动增长率随激励频率的变化(正弦波)<br/>Fig.9 Variation of disturbance growth rate with excitation frequency(sine wave)

图9 扰动增长率随激励频率的变化(正弦波)
Fig.9 Variation of disturbance growth rate with excitation frequency(sine wave)

图10 激励频率对应的射流形态<br/>Fig.10 Jet shape corresponding to excitation frequency

图10 激励频率对应的射流形态
Fig.10 Jet shape corresponding to excitation frequency

图11 激励频率对液滴粒径的影响<br/>Fig.11 Effect of excitation frequency on droplet size

图11 激励频率对液滴粒径的影响
Fig.11 Effect of excitation frequency on droplet size

图12 位移幅值对应的射流破碎形态<br/>Fig.12 Jet breaking shape corresponding to displacement amplitude

图12 位移幅值对应的射流破碎形态
Fig.12 Jet breaking shape corresponding to displacement amplitude

图13 位移幅值对射流破碎特性的影响<br/>Fig.13 The influence of displacement amplitude on jet breaking characteristics

图13 位移幅值对射流破碎特性的影响
Fig.13 The influence of displacement amplitude on jet breaking characteristics

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备注

引言

1 实验装置及实验方法

2 实验结果与讨论

3 结论

期刊信息