欠热沸腾两相系统声压波动时间序列模型的研究

Experimental Model of Subcooled Boiling Sound Pressure Oscillation in Two Phase Tube——Time Series Analysis

通过对欠热沸腾两相热声效应的实验研究及声压波动时序的动态数据采集，运用时间序列分析方法进行实验建模，建立近似ＡＲ时序模型．在此基础上得到系统声压波动时序的自回归功率谱并分析其频谱特性；发现了管内欠热沸腾热声振荡的“频率聚合”特性；近似验证了系统“声放大”区的存在．揭示了系统自组织的非线性发展过程和自激振荡特征．最后，探讨了时序模型的应用——声压波动时序的短期预测．

By dynamic data acquisition system(DDAS) and through time series analysis, the subcooled boiling thermoacoustic effect in two phase tube is investigated and an AR model is established. Based on the model, autoregressive power spectrum of the system sound time series is obtained and analysis to its frequency characteristics are presented, which leads to the observation of “frequency combination effect” of subcooled boiling thermoacoustic oscillation. Meanwhile, the existence of “acoustic amplification” region is verified, which gives rise to the non linear development of self organization and self excited oscillation. Finally, as an application of time series analysis, the short term prediction to the sound pressure oscillation is presented and discussed.