scholarly journals A study of the onset of oscillatory flow in a czochralski growth melt and its suppression by a magnetic field.

1989 ◽  
Vol 55 (517) ◽  
pp. 2610-2617 ◽  
Author(s):  
Tetsuo MUNAKATA ◽  
Ichiro TANASAWA
Keyword(s):  
Magnetic Field ◽  
Oscillatory Flow ◽  
Czochralski Growth

Numerical Study of the Effect of Magnetic Fields on Melt-Crystal Interface-Deflection in Czochralski Crystal Growth

2003 ◽  
Author(s):  
Lijun Liu ◽  
Koichi Kakimoto
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Numerical Study ◽  
Silicon Crystal ◽  
Czochralski Growth ◽  
Thermal Flow ◽  
Interface Shape ◽  
Convective Thermal ◽  
And Control ◽  
Crystal Interface

In order to control the impurity distribution and remove defects in a crystal grown in Czochralski growth for high quality crystals of silicon, it is necessary to study and control the melt-crystal interface shape, which plays an important role in control of the crystal quality. The melt-crystal interface interacts with and is determined by the convective thermal flow of the melt in the crucible. Application of magnetic field in the Czochralski system is an effective tool to control the convective thermal flow in the crucible. Therefore, the shape of the melt-crystal interface can be modified accordingly. Numerical study is performed in this paper to understand the effect of magnetic field on the interface deflection in Czochralski system. Comparisons have been carried out by computations for four arrangements of the magnetic field: without magnetic field, a vertical magnetic field and two types of cusp-shaped magnetic field. The velocity, pressure, thermal and electromagnetic fields are solved with adaptation of the mesh to the iteratively modified interface shape. The multi-block technique is applied to discretize the melt field in the crucible and the solid field of silicon crystal. The unknown shape of the melt-crystal interface is achieved by an iterative procedure. The computation results show that the magnetic fields have obvious effects on both the pattern and strength of the convective flow and the interface shape. Applying magnetic field in the Czochralski system, therefore, is an effective tool to control the quality of bulk crystal in Czochralski growth process.

Oscillatory Flow of a Magnetic Fluid in a Pipe at Low Frequency Range Under a Magnetic Field: Phase Difference of Pressure

2003 ◽  
Author(s):  
Kunio Shimada ◽  
Shigemitsu Shuchi ◽  
Shinichi Kamiyama
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Phase Difference ◽  
Mass Concentration ◽  
Oscillatory Flow ◽  
Low Frequency ◽  
Nonuniform Distribution ◽  
Straight Pipe ◽  
Number Range ◽  
Steady Magnetic Field

We made on numerical analysis of phase difference between pressure along the pipe axis and given oscillatory flow velocity in an straight pipe under a nonuniform steady magnetic field. In the analysis, a few cases under the assumption of numerical condition were conducted on: the first is taking into account the least compressibility of the fluid with using the obtained experimental data of the bulk modulus, the second taking into account the nonuniform distribution of mass concentration of particles, and the thrid taking into account the aggregation with the number of aggregated particles proposing as a prorate spheroid. By considering the three effects of the least compressibility and the nonuniform distribution of mass concentration, the aggregation as a prorate spheroid, the phase difference varies quantitatively at the lowest Womersley number range. And then, the numerical results were compared with the experimental data.

Applications of Oscillatory Flow of Magnetic Fluid as Active Damper and Actuator

1999 ◽  
Vol 13 (14n16) ◽  
pp. 2213-2220 ◽  
Author(s):  
Shinichi Kamiyama
Keyword(s):  
Magnetic Field ◽  
Magnetic Fluid ◽  
Applied Magnetic Field ◽  
Oscillatory Flow ◽  
Mass System ◽  
Active Damper

Study on the control of vibration of a spring-mass system attached to a piston immersed in a magnetic fluid by controlling the applied magnetic field is conducted theoretically and experimentally to develop the magnetic fluid active damper and actuator.

Dynamic accuracy of the electromagnetic flowmeter

1965 ◽  
Vol 20 (1) ◽  
pp. 142-147 ◽  
Author(s):  
M. F. O'Rourke
Keyword(s):  
Magnetic Field ◽  
Pulsatile Flow ◽  
Output Signal ◽  
Oscillatory Flow ◽  
Electromagnetic Flowmeter ◽  
Sine Wave ◽  
Dynamic Calibration ◽  
Phase Lag ◽  
Dynamic Accuracy ◽  
Sinusoidal Flow

Dynamic calibration of electromagnetic flowmeters was performed by resolving the output signal when sinusoidal flow of known characteristics was pumped through the probe. In two instruments amplitude and phase were found to be frequency dependent in the range 0–20 cycle/sec; the magnitude of these effects was not insignificant as many have assumed. In a sine wave instrument using a variety of probes, both amplitude and phase increased linearly with frequency: the former increasing by 0.57% per cycle per second, the latter by 3.6° per cycle per second. In the square wave flowmeter at 0 damping, amplitude decreased significantly above 5 cycle/sec, while phase lag increased by 4.9° per cycle per second. These effects are concluded to be due to the output filtering network. In the sine wave instrument it was demonstrated that magnetic field nonuniformity within the probe did not alter the accuracy in recording steady or oscillatory flow. It was thus possible to construct a small short flowmeter probe having narrow electromagnet coils, and it is expected that this probe should cause minimal interference to pulsatile flow patterns. magnetic fields flowmeter probes; frequency-response flowmeter Submitted on April 16, 1964

Role of Slip Velocity on the Oscillatory Flow of Blood Through a Porous Vessel in the Presence of Heat Source and Chemical Reaction

2014 ◽  
Vol 30 (2) ◽  
pp. 209-218 ◽  
Author(s):  
A. Sinha ◽  
G. C. Shit
Keyword(s):  
Magnetic Field ◽  
Chemical Reaction ◽  
Slip Velocity ◽  
Oscillatory Flow ◽  
Internal Heat ◽  
Internal Heat Generation ◽  
Suction Velocity ◽  
Heat Generation Or Absorption ◽  
Nicolson Scheme

ABSTRACTOf concern in this paper is a problem motivated towards studying the influence of slip velocity on heat and mass transfer in the unsteady flow of blood through a porous vessel, when the lumen of the vessel has turned into a porous structure with internal heat generation or absorption in the presence of chemical reaction. It is assumed that the influence of a uniform magnetic field acts normal to the flow and the permeability of the porous medium fluctuates with time. The suction velocity is also taken to be oscillates periodically. The problem is solved numerically by using Crank-Nicolson scheme. The computational results are presented graphically for the velocity, temperature and concentration distribution as well as the variation of skin-friction co-efficient, Nusselt number and Sherwood number for various values of the parameters involved in this analysis. The study reveals that the flow is appreciably influenced by the presence of a magnetic field and slip velocity.

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