A simple method is developed in this paper to solve two-dimensional nonlinear steady inverse heat conduction problems. The unknown boundary conditions can be numerically obtained by using the iteration and modification method. The effect of measurement errors of the wall temperature on the algorithm is numerically tested. The results prove that this method has the advantages of fast convergence, high precision, and good stability. The method is successfully applied to estimate the convective heat transfer coefficient in the case of a fluid flowing in an electrically heated helically coiled tube

In the present investigation, both pressure fluctuations and differential pressure signals were measured for oil-gas-water multiphase piping flow in wide ranges of flow parameters in horizontal pipe. The signal features were extracted and analyzed, which included time domain features, frequency domain features and fractal features. Both liquid velocity and oil fraction have tremendous influence on the feature analysis, which all the feature have bad clustering and bad separability for the same flow pattern or different flow pattern respectively. It is proved that the recognition methods, RMS of the pressure, PDF or PSD of differential pressure fluctuation, are not able to be employed widely in the industrial applications. The pressure fluctuations exhibit chaotic characters and are influenced by flow patterns. The regulations to identify the special flow pattern are obtained basing on the joint feature analysis. The online intelligent recognition of flow patterns is proposed which is a fusion method combining the special regulations and the pattern recognition. The proposed method was examined in the oil-gas-water loop and the results showed that bubble flow, stratified flow, intermittent flow and annular flow could be identified with more than 90% accuracy.

With the development of supercritical fluids technology, more and more attention is being paid to the study of flow and heat transfer under supercritical conditions. In order to better understand the influence of gravity on the flow and heat transfer of supercritical fluids, with the CFD software FLUENT 6.0, a numerical study has been conducted for the developing laminar flow and heat transfer of water in a smooth vertical tube under supercritical pressure. The flow and heat transfer have been studied with the inlet Reynolds number ranging from 500 to 2000, Grashof number er ranging from1

从理想的单气泡运动物理模型和离散正交小波与统计相结合的信号处理技术研究了泡状流压力波动的机理与多尺度的频规律，得到以下结论：泡状流的压力波动主要来源于气泡的运动和诱导湍及液相湍流，其中在低流速下前者产生的压力波动幅度大于后两者；存在一个临界频率，低于该频率压力信号均方根随频率的增加面增加，高于该频率压力信号均方根随频率的增加而减少；发生流型转变时压力信号的时频特征发生明显改变，最大均方根出现在更低的频率区。

实验研究了螺管内绝热和沸腾汽液两相流动时压力波动特性，分析了热流密度对压力波动的影响规律。结果表明沸腾时波动的均方根和分形参数（分维数、关联维数和Kolmogorov熵）与绝热两相流明显不同，加热热流密度的大小影响各特征参数的大小及其随干度的变化规律。未考虑流密度影响的流型图或流型转变准则只能在小热流密度时使用。