Correlations for the ignition delay times of hydrogen/air mixtures

Correlations for the ignition delay times of hydrogen/air mixtures were developed using the method of High Dimensional Model Representation (HDMR).The hydrogen/air ignition delay times for initial conditions over a wide range of temperatures from 800 to 1600 K,pressures from 0.1 to 100 atm,and equivalence ratios from 0.2 to 10 were first calculated utilizing the full chemical mechanism.Correlations were then developed based on these ignition delay times.Two forms of correlations were constructed:the first one is an overall general model covering the whole range of the initial conditions;while the second one is a piecewise correlation model valid for initial conditions within different sub-domains.The performance of these correlations was studied through comparison with results from the full chemical mechanism as well as experimental data.It was shown that these correlations work well over the whole range of initial conditions and that the accuracy can be significantly improved by using different piecewise correlations for different sub-domains.Therefore,piecewise correlations can be used as an effective replacement for the full mechanism when the prediction of chemical time scale is needed in certain combustion modeling.     

桥梁结构基于高维模型拟合响应面的参数识别

为提高响应面法在桥梁结构参数识别中的计算精度,提出了基于高维模型拟合响应面的参数识别方法.即采用HDMR响应面法拟合结构响应面,并基于该响应面进行结构参数的识别.研究了HDMR响应面的基本构造方法,阐述了在响应面基础上通过有约束最小二乘优化实现参数识别的一般过程.以一座连续梁及一座独塔斜拉桥为算例进行分析,探讨了该方法在结构参数识别中的计算精度及效率.结果表明,相比传统响应面法,该方法在计算精度上具有显著优势.同时也验证了该方法在大型桥梁结构参数识别中的可靠性和适用性.