Chaotic forecasting of time series of heat-transfer coefficient for an evaporator with a two-phase flow
Chaotic forecasting of time series of heat-transfer coefficient for an evaporator with a two-phase flow
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DOI：
10.1016/j.ces.2004.09.052
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发表时间：
2005-02
影响因子：
4.7
通讯作者：
Mingyan Liu;Juan-ping Xue;Ai-hong Qiang
中科院分区：
文献类型：
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作者：
Mingyan Liu;Juan-ping Xue;Ai-hong Qiang
采用混沌预测和局部非线性短期预测方法对汽液两相沸腾蒸发器传热膜系数时间序列进行了预测。该方法以相空间重构理论为基础，建立了数据驱动形式的数学模型进行预测。将该方法预测的传热膜系数信号与实验测量结果进行了比较。与以往的研究不同的是，本文既从时间轨迹的角度进行比较，又从宏观或一般特征的角度进行比较。对实验测量和预测得到的时间序列，除了计算其平均值、平均偏差和标准偏差等时均统计特性外，还计算了功率谱、相平面图和混沌不变量（包括关联维数和Kolmogorov熵），并进行了比较。将实测时间序列的计算值与混沌预测方法预测的时间序列的估计值进行了比较，结果表明两者吻合较好。有限的时间长度和准确的预测表明系统是混沌的。通用参数的比较结果表明，混沌预测方法对两相流沸腾系统的传热特性预测是有效的，混沌预测方法有可能成为对此类蒸发器进行有效热流控制的工具。
The time series of heat-transfer film coefficient for an evaporator with a vapor–liquid two-phase boiling flow were forecasted by the chaotic prediction or the local nonlinear short-term prediction. The forecasting method was based on the phase space reconstruction theory and a mathematic model in the form of datum driving had been developed to carry out the prediction. The signals of heat-transfer film coefficients predicted by this method were compared with those obtained from the experimental measurements. Different from the previous work, the comparisons in this work were done both from the point of view of the time trajectory and from the point of view of macroscopic or general characters. Besides the time-averaged statistics characteristics, such as the average value, average deviation and standard deviation, the power spectrum, phase plane map and chaotic invariants including the correlation dimension and Kolmogorov entropy had been calculated and been compared for the time series obtained both from the experimental measurement and from the forecast. The comparison for each parameter between the value calculated from the time series measured and that estimated from the time series forecasted by the chaotic forecast method shows satisfactory agreement. The limited length in time with an accuracy prediction indicates that the system is chaotic. The agreement of the comparison of the general parameter indicates that the chaotic prediction is effective for the estimations of the heat transfer characteristics of the two-phase flow boiling system and that the chaotic prediction method may be a potential tool for the effective thermo-fluid control for such evaporators.