Jianxin Xu

Quantifying the evolution of flow boiling bubbles by statistical testing and image analysis: toward a general model.

A new index, the estimate of the error variance, which can be used to quantify the evolution of the flow patterns when multiphase components or tracers are difficultly distinguishable, was proposed. The homogeneity degree of the luminance space distribution behind the viewing windows in the direct contact boiling heat transfer process was explored. With image analysis and a linear statistical model, the F-test of the statistical analysis was used to test whether the light was uniform, and a non-linear method was used to determine the direction and position of a fixed source light. The experimental results showed that the inflection point of the new index was approximately equal to the mixing time. The new index has been popularized and applied to a multiphase macro mixing process by top blowing in a stirred tank. Moreover, a general quantifying model was introduced for demonstrating the relationship between the flow patterns of the bubble swarms and heat transfer. The results can be applied to investigate other mixing processes that are very difficult to recognize the target.

Analysis of Sunspot Time Series (1749-2014) by Means of 0-1 Test for Chaos Detection

We present here an implementation of the novel test called binary 0-1 test which is a chaos detection method and applied to the sunspot time series. This method seems to represent a useful improvement for the non-stationary time series chaotic characteristic analysis and computationally low cost. It is concluded that the monthly mean relative sunspot time series from January 1749 to December 2014 is inherently chaotic based on the outputs of the test. Additionally, a more detailed characterization of the sunspot time series is carried out on Lyapunov spectrum basis.

Simulation model for crane scheduling in workshop of steel-making plant based on MAS

In order to solve the NP-hard problem of crane scheduling, a simulation method of crane scheduling in workshop of steel-making plant is presented based on the multi agent system (MAS). According to the characteristics of crane scheduling, a MAS-based model for simulating crane scheduling in melt shop is built. The scheduling system mainly includes crane agent groups, work station agent groups and coordination management agent. The operation principles can be described as follow. Firstly, the global target is introduced into the system. Secondly, the global target is changed to local targets by the time backward inferring algorithm in the coordination management agent. Then, the target work station is selected by the local targets and rules. Finally, crane agent groups choose suitable crane to finish the transportation tasks. The research works show that the simulation method of crane scheduling in workshop of steel-making plant based on MAS is feasible, and it can depict the basic characteristics of cranes in workshop of steel-making plant efficiently. The method has the extensive applicability to optimize the system of crane scheduling.

An Assessment of the Effects of Micron-Particle Aggregation on the Performance of Zinc-Silica Composite Coatings Using Betti Numbers

This paper investigates the assessment of the mixing effect of zinc-silica composite electrolyte using particle image velocimetry (PIV). In particular, we considered the deposition of silica particles using a stirring tank, which provides strong evidence for characterizing the mixing effects of flow field. A method to extract meaningful parameters to evaluate particle distribution from digital images recorded by the PIV technique during the electrodeposition process is applied. The Betti numbers of binary images of silica particles mixing were calculated using the CHomP software, which was used to evaluate mixing homogeneity and nonhomogeneity in flow field. An analysis of the performance of zinc-silica composite coatings is performed in an attempt to test and verify the assessment of the effects of micron-particle aggregation. Good correlations between calculated and experimental testing results illustrate the potential of the Betti numbers method to quantitatively evaluate micron-particle aggregation. This offers new possibilities to monitor the deposition of silica particles and to analyze flow field during the electrodeposition progress.

Analysis and Modeling of Time-Correlated Characteristics of Rainfall-Runoff Similarity in the Upstream Red River Basin

We constructed a similarity model (based on Euclidean distance between rainfall and runoff) to study time-correlated characteristics of rainfall-runoff similar patterns in the upstream Red River Basin and presented a detailed evaluation of the time correlation of rainfall-runoff similarity. The rainfall-runoff similarity was used to determine the optimum similarity. The results showed that a time-correlated model was found to be capable of predicting the rainfall-runoff similarity in the upstream Red River Basin in a satisfactory way. Both noised and denoised time series by thresholding the wavelet coefficients were applied to verify the accuracy of model. And the corresponding optimum similar sets obtained as the equation solution conditions showed an interesting and stable trend. On the whole, the annual mean similarity presented a gradually rising trend, for quantitatively estimating comprehensive influence of climate change and of human activities on rainfall-runoff similarity.

Notice of Retraction Study on the strategies of CFD technology application

Taking several flow-heat transfer coupled models as examples, and combining the experience of using the large scale commercial computational fluid dynamics software Fluent and Comsol Multiphysics, this paper further explores the key general problems in the CFD technology application from three aspects of modeling strategy, solution strategy and post-processing strategy.

Modeling simulation and optimization study of the mode of “route with one open ladle from BF to BOF” in BF - BOF region based on WITNESS

The paper introduces the application of software Witness, and discusses the cumulative effect of ladle caused by waiting time and the methods of using the software Witness in the simulative interface mode of “route with one open ladle from BF to BOF” in BF -BOF region. The author studies the factors to “bottlenecks” phenomenon in the modeling simulation and the factors to cumulative effect by waiting time of the ladle. Based on the results of model simulation, the author not only points out the measures to resolve this problem, but also proposes the ways to alleviate the cumulative effect through improvements by setting the parameter on the modeling simulative system.

Notice of Retraction Fractal analysis of mixing time in gas-liquid-solid stirred reactor based on CFD and image processing

In order to predict gas-liquid-solid multiphase mixing effect in the gas-liquid-solid three-phase reactors, a novel method based on image processing technology, fractal dimension and CFD technology is introduced in this work. Each pattern produced by phase transition in the stirred reactor are continuously eroded and binarized five times. Evolution profile of the fractal dimension slope value P of each five binary patterns is used to evaluate the mixing time. Comparing with the classical fractal method, our method can more clearly and accurately reflect the trends of mixing process. The results illustrate effect of mixing time on flow rate and submerged length. A optimization model has been developed to select the best process parameters, and hydraulic model experiments verify the validity of this method.