摘要
应用功率谱、自相关系数、吸引子相图、关联维数等分析工具,对汽-液两相流动沸腾蒸发系统的传热系数时间序列进行了定性和定量混沌研究。研究结果为:时间序列的功率谱在半对数坐标下呈指数下降趋势;自相关系数随时间的推移而减小;吸引子相图呈现精细结构;关联维数随嵌入维数的增大而趋于一个稳定的分数值。这说明汽-液两相流动沸腾蒸发系统呈现混沌特性。在此基础上,应用临近点相似混沌预测法对不同加热蒸汽压力(0.11MPa、0.13MPa、0.15MPa)下的传热系数时间序列进行了混沌预测。结果表明:预测值和实验值在有限时间长度内吻合程度较好;预测的平均相对误差随加热蒸汽压力的增加而增大;高精度预测时间长度随加热蒸汽压力增加而减小。这表明该系统具有短期可预测性。
Qualitatively and quantitatively chaotic analyses of time series of heat transfer film coefficient in an evaporator with vapor-liquid boiling flow were carried out by using the power spectrum, autocorrelation function, phase plane map of attractor and correlation dimension. It could be seen that exponential decrease is exhibited in the power spectrum of the time series at semi-logarithmic coordinate, the value of autocorrelation function estimated from the time series decreases gradually with the increase of the time delay, the phase plane map of attractor reconstructed from the time series shows fine geometry structure, and the correlation dimension calculated from the time series decreases with the increase of the embedded dimension. These results indicate that the evaporation system with vapor-liquid boiling flow is chaotic. Meanwhile, the time series of heat transfer coefficient at different pressures of steam （P = 0.11 MPa, 0.13 MPa, 0.15 MPa） were forecasted by the method of chaotic prediction. The predicted values consist with the measured values well in a limited length of prediction time. The prediction results show that the time series of heat transfer coefficient can be predicted with high accuracy in a limited time length, and the average relative error increases with the increase of the time length and the increase of steam pressure.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2006年第1期12-17,共6页
Journal of Chemical Engineering of Chinese Universities
基金
国家自然科学基金(20106012)。
关键词
汽-液沸腾
传热系数
混沌
混沌预测
重构相空间
关联维数
vapor-liquid boiling
heat transfer coefficient
chaos
chaotic prediction
phase space reconstruction
correlation dimension
