Retracted article – Experimental study on dynamic deformation of free surface under surrounding gas flow

MATEC Web of Conferences, Jan 2016

This article has been formally withdrawn on ethical grounds because it contains an instance of plagiarism.It should not be cited or referred to in the future. Request approved by the Publisher on March 15, 2016.

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Retracted article – Experimental study on dynamic deformation of free surface under surrounding gas flow

MATEC Web of Conferences Experimental study on dynamic deformation of free surface under surrounding gas flow Ruquan Liang 0 Xiaoyuan Li 0 linyang Zhu 0 Zhihui Zhang 0 0 Key Laboratory of National Education Ministry for Electromagnetic Processes of Materials, Northeastern University in ShenYang , CN In this paper, the dynamic deformation of the free surface of the liquid bridge caused by the surface shear flow is studied experimentally 5cSt (Prandtl number Pr=68) is taken as the material of liquid bridge and nitrogen as the airflow. The shape of the liquid bridge is captured by a high-speed camera and processed by MATLAB. The boundary extraction technique is used to obtain the coordinate points of the liquid bridge surface. The volume ratio of the liquid bridge and the shear flow velocity have a vital influence on the deformation of the free surface. When the direction of the airflow is against as the gravity and the volume ratio is 1, the deformation magnitude of the free surface decreases with the increase of volume ratios. In this process, the deformation curves always present a sinusoidal pattern. 1 Introduction The dynamic deformation of the free surface of liquid bridge is closely related with production of high-quality single crystal in floating zone method. Therefore, the conclusion driven by this paper can directly apply to the growth of melt crystal. In physical experiments, we use the ideal isothermal model to improve the quality of silicon crystal. Deformation of an isothermal interface is extremely related to a co-axial gas flow when enter from the bottom to the top, which was discussed by Gaponenko[1,2], and they reported that the linear velocity of gas almost determined the free surface deformation. The tendency that surface deformation grows with the volume ratio V quasi-linearly was predicted by Gaponenko[3]. After a slow decaying of the period, the new oscillations are generated. The new liquid bridge decayed much faster. A linear dependence is not observed for all volume ratios, despite the small Reynolds number (280 < Reg < 560) is studied by Matsunaga[4]. The dynamic deformation displays a strong dependence on the liquid volume ratio and the direction of the gas stream parallel to the interface. The shape of liquid bridge which exists between two fixed support columns is usually maintained to be cylindrical by surface tension. In this paper, the experiment is carried out about dynamic deformation of free surface under the normal gravity environment. The object of this experiment is to study the adiabatic gas-liquid two-phase flow system with isothermal and cylindrical geometry. The dynamic deformation of the free surface of the liquid bridge is studied. 2 Experiment Establishment and Experiment Process The equipment includes a high-speed camera, a liquid bridge support frame, a astigmatism film and a back light. The liquid bridge generation equipment is fixed on the horizontal experimental platform to adjust the liquid bridge to proper height. The micro-syringe is used to control the primary volume of silicone oil. The cylinder the sleeve, the white back light, the camera and the liquid bridge generation equipment are all set to be ready. Then, the gas enters the cylinder sleeve, after the ventilation is stable; the high-speed camera begins to shoot the shape of liquid bridge. The coordinate point data of liquid bridge surface is obtained by using boundary extraction technology and numerically simulated by ORIGIN software to form the figures, and the dynamic deformation of free surface of liquid bridge is acquired. In the experiment, the aspect ratio of liquid bridge is defined as Γ =d/R0, where d and R0 denote the height and support radius, respectively. Figure 1 is a simple diagram of the experiment. The liquid bridge is surrounded by a vertical transparent glass sleeve with R0=3mm and Rout=5mm remaining unchanged. Gas enters the glass sleeve from the lower part and flows through the annular tube of size. Rh= 2 Rout - R0 Reg=2 Rout R0 U0/Vg (1) (2) With constant flux Q. Reynolds number Reg is determined by hydraulic diameter, Digital images are acquired at 50 frames/seconds for 5 seconds. The stable shape of liquid bridge can be obtained by calculating the mean value of these images. Repeat above process for each gas flux. The free surface contour is determined by the physical parameters of bilateral liquid and geometric parameters of the system. But generally, the effect of flow on the dynamic deformation of free surface is usually described by the capillary number Ca[5]. Ca = 6.0 10 4U0G2 f (V ) Ca = vg gU0 f (R0, Rout , d ,V ) The coefficient is determined by the volume ratio V and the gas velocity U0. When the aspect ratio is Γ =1, the coefficient decreases from 1 to 0.5 with the volume ratio increasing from 0.8 to 1.07. The capillary number increases with the airflow velocity increasing from 1m/s to 2m/s. The predicted dynamic deformation of the free surface is (...truncated)


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Ruquan Liang, Xiaoyuan Li, linyang Zhu, Zhihui Zhang. Retracted article – Experimental study on dynamic deformation of free surface under surrounding gas flow, MATEC Web of Conferences, 2016, 40, DOI: 10.1051/matecconf/20164006002