伴随气泡和气穴低压管路瞬态的建模与分析

在航空航天液压系统中,为了合理地预测伴随气泡和气穴低压管路压力瞬态脉动,给出了用来描述管路流动瞬态特性的数学模型.采用有限差分法实现了偏微分方程中空间域的偏导,并建立了计算有效体积弹性模量、摩擦阻力项、气泡和气穴体积的数学模型.利用遗传算法对模型中三个参数即油中的初始气泡体积、气体析出时间常数和气体溶解时间常数进行参数辨识,得到了参数辨识以后的低压管路压力瞬态脉动模型.通过对仿真结果和实验结果的分析比较,表明该低压管路瞬态模型用于计算伴随气泡和气穴的压力瞬态脉动是可行的.

Modeling and analyzing of low pressure pipeline transients accompanying gas bubbles and cavitation

In order to predict pressure transients accompanying gas bubbles and cavitation inside low pressure pipeline in hydraulic system of aerospace,pressure transient mathematical model was given to describe the flow behavior in the pipeline.By using finite difference method,partial differential terms of spatial dimension in differential equations can be calculated.Mathematic models were presented for calculation of effective bulk modulus,friction,gas bubble and cavitation volume during the transients.The model of low pressure pipeline transients involves three parameters,i.e.initial gas bubble volume in oil,gas releasing time constant and resolving time constant.By making use of genetic algorithms(GA),parameter identification for the mathematical model of pressure transients was performed.Thus the model with parameters identified from GA was obtained and simulated.Comparison between simulation results and experimental data shows that low pressure transient model is capable of predicting pressure pulsation accompanying gas bubbles and cavitation.