The histories of differential pressure fluctuations and their Fast Fourier Transform spectrum have close relation with the flow regimes.Unfortunately,each type of flow regime is very difficult or impossible to be dist...The histories of differential pressure fluctuations and their Fast Fourier Transform spectrum have close relation with the flow regimes.Unfortunately,each type of flow regime is very difficult or impossible to be distinguished from the other on the basis of the fluctuations or the spectrum.The present paper provides a feasible solution, which the gas-liquid two-phase flow regimes can be recognized automatically and objectively on the basis of the combination of the Counter Propagation Network (CPN) and the FFT spectrum of the differential pressure fluctuations. The CPN takes advantages of simpler algorithm and fast training processes.Furthermore,it does not require a great deal of samples.The recognition possibility is determined by the clustering results of the Kohonen layer in the CPN.With the presented test cases,the possibility can be higher than 90 percent for different liquid phase velocity.展开更多
In this paper, a simple and effective method is presented to solve the two-dimensionalnonlinear steady inverse heat conduction problem. From the finite difference equation of heatconduction, the convective heat transf...In this paper, a simple and effective method is presented to solve the two-dimensionalnonlinear steady inverse heat conduction problem. From the finite difference equation of heatconduction, the convective heat transfer coefficient, which is the unknown boundary, can benumerially obtained with this method. By taking the electrically heated helically coiled tubeas an experimental case, this method is successfully applied. It is proved by numerical teststhat this method takes the advantages of fast coverging, high precision and good stability.It can also be extended to the complex geometrics problems.展开更多
文摘The histories of differential pressure fluctuations and their Fast Fourier Transform spectrum have close relation with the flow regimes.Unfortunately,each type of flow regime is very difficult or impossible to be distinguished from the other on the basis of the fluctuations or the spectrum.The present paper provides a feasible solution, which the gas-liquid two-phase flow regimes can be recognized automatically and objectively on the basis of the combination of the Counter Propagation Network (CPN) and the FFT spectrum of the differential pressure fluctuations. The CPN takes advantages of simpler algorithm and fast training processes.Furthermore,it does not require a great deal of samples.The recognition possibility is determined by the clustering results of the Kohonen layer in the CPN.With the presented test cases,the possibility can be higher than 90 percent for different liquid phase velocity.
文摘In this paper, a simple and effective method is presented to solve the two-dimensionalnonlinear steady inverse heat conduction problem. From the finite difference equation of heatconduction, the convective heat transfer coefficient, which is the unknown boundary, can benumerially obtained with this method. By taking the electrically heated helically coiled tubeas an experimental case, this method is successfully applied. It is proved by numerical teststhat this method takes the advantages of fast coverging, high precision and good stability.It can also be extended to the complex geometrics problems.
