• Korean Chemical Engineering Research
• /
• v.48 no.4
• /
• pp.462-469
• /
• 2010

Gas-liquid 2 phase processes are usually used in chemical, biochemical, environmental engineering and food process. For optimizing these processes, understanding bubble's precise movement and shape are needed. Bubble's movement and shape are effected by liquid's properties-viscosity, surface tension and bubble's properties-size, velocity. This paper deals with experimental data of bubble's movement and shape in high viscous silicone oil. Also, drag coefficient and deformation factor given by other researcher's papers and books are used to predicting and comparing bubble's terminal velocity, drag coefficient, deformation factor and shape with experimental value. Experimental data show that bubble moves faster when it moves in lower viscous silicone oil and it's drag coefficient is bigger when it moves in high viscous silicone oil. Bubble's shape is close to sphere when moving in high viscous silicone. Formulas proposed by Batchelor expect most accurate prediction for bubble's velocity and drag coefficient. Bubble's 2D shape predicted by Batchelor's energy balance, drag coefficient and deformation factor show excellent agreement with experimental bubble's 2D shape.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.27 no.12
• /
• pp.847-851
• /
• 2014

The characteristics of dielectric constant and $tan{\delta}$ of low viscosity silicone oils with changing degree of polymerization were investigated. The result shows dipole loss mechanism at low temperature range. The dielectric loss in the range of low frequencies are predominantly of ionic nature with temperature increase. The peak of dielectric loss is the detrapping of the electrons which is were trapped in the localized level of the silicone oils at the frequency of 30 kHz. The increase of ionic conduction is attributed to the presence of ionizable oxidation products and their increased dissociation feature. The activation energy ${\Delta}H$ and dipole moment ${\mu}_d$ were increased whit increasing degree of polymerization.

• Journal of Electrical Engineering and Technology
• /
• v.1 no.4
• /
• pp.528-533
• /
• 2006

Electrical discharges may occur in gas, liquid as well as solid insulating materials. This paper describes the investigation results on the discharges in air, silicone oil and low density polyethylene (LDPE) using needle plane electrode system under AC voltage of 50 Hz. The experimental results showed that for discharge in air (corona), discharge pulses were concentrated around the peak of applied voltage at negative half cycle. For silicone oil positive as well as negative discharges were observed which concentrated around the peak of applied voltage. The positive pulse number was smaller but the magnitude was higher than that of negative discharge. Discharges in void took place at wider range of phase of applied voltage. The unbalance in pulse number and magnitude similar to that of oil discharges were observed. For electrical treeing in LDPE, the discharges were spread before the zero cross of the applied voltage up to the peak at both positive and negative half cycles. The discharge pulse sequence analysis indicated that the PD occurrence in air, oil and void were strongly affected by the magnitude of applied voltage. However, for electrical treeing it was observed that the discharge occurrence was strongly affected by the time derivative of the applied voltage (dv/dt).

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.8
• /
• pp.39-47
• /
• 2011

The motion of a conductive spherical particle under uniform electric field is investigated in order to find a suitable method for removing the conducting solid impurities contained in liquid plastic. When the positive dc voltage applied to the upper electrode, the vertical up-and-down motion of a charged particle by electrostatic force is observed by a charge-coupled device (CCD) camera or a high-speed video camera. The experimental data of the static threshold voltage by which the particle starts to move toward the counter electrode in air or silicone oil are in good agreement with theoretical value. When the applied voltage is larger than the static threshold voltage, the particle motion pattern in silicone oil consists of four stages: upward motion, stopping at the upper electrode, downward motion and stopping at the lower electrode. The stopping motion on the electrode is thought to be caused by the liquid flow accompanied by the particle motion. The particle charge calculated by integrating the pulse current, which is generated by the charge exchange between the electrode and the particle, is approximately 0.1~0.25 times of the theoretical value. This study is expected to help understand the electric properties of microparticles in oil circuit breaker (OCB) and oil transformer and improve their performance and longevity.

• Journal of the Korean Applied Science and Technology
• /
• v.12 no.1
• /
• pp.29-34
• /
• 1995

Silicone softner(SSN-3) for permanent press(PP) finish was prepared by blending beef tallow hardened oil for Improving softness, water, the emulsion, which was synthesized from pentaerythritol monostearate as a softening component and silicone oil KF-96 as a lubricating component. The prepared SSN-3 and the PP finishing resin were applied to PP finishing cotton broad cloth and P/C gingham samples using one bath method. The properties such as crease recovery, tear strength, bending resistance test were tested. The samples treated with SSN-3 and PP finishing resin have improved properties, compared with nontreated samples, those treated only with PP finishing resin, those treated with commercial PP finishing softners and PP finishing resin. Also from the bending resistance test, the two kinds of fabric samples treated with SSN-3 of 3% showed grade 5 and these were good enough in feeling.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2002.04a
• /
• pp.451-456
• /
• 2002

This paper describes the properties of Temperature-Viscosity characteristics of hydrous and anhydrous ER fluids containing starch and titanium particle in silicone oil. ER effects arise from electrostatic forces between the starch particles and titanium particles dispersed in the electrically insulating silicone oil induced when electric field is applied. ER fluids under electric field have been found to provide resonable estimates of ER fluid viscosity variation characteristics. Yield shear stress of the ER fluids were measured on the couette cell type rheometer as a function of electric fields. The outer cup is connected to positive electrode(+) and bob becomes ground(-). The electric field is applied by high voltage DC power supply. In this experiment shear rates were increased from 0 to 200/equation omitted/ in 2 minutes.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.10
• /
• pp.1812-1817
• /
• 2008

A cooling system for microelectronics is becoming more important as its surface heat density is projected to reach that of the sun surface. The existing technologies using natural and forced convection are limited to solve the problems. Recently, an electrohydrodynamic driven flow is studied as one of the means to cope with this problems. A new method, utilizing a needle-centered nozzle electrode, has been proposed and investigated. The I-V characteristics of the nozzle electrode for deionized water and silicone oil were significantly different from that of without liquid, which might be due to the liquid drop covered on the nozzle tip by the EHD force acting near the needle tip. Results showed that the liquid pumping rate and flow efficiency of the nozzle electrode were very high, especially for the silicone oil. Theoretical analysis also showed the effectiveness of the needle electrode centered in the ceramic nozzle, which, however, can be a means as a liquid pump.

• Microbiology and Biotechnology Letters
• /
• v.20 no.5
• /
• pp.583-587
• /
• 1992

This study was conducted in order to optimize the media composition and cultural conditions for kasugamycin production by Streptomyces kasugaensis. The optimum culture conditions are pH 6.6 (before sterilization) and $28^{\circ}C$ for the production of kasugamycin. The kasugamycin concentration was not increased when silicone oil as antifoam agent was added. The addition of water during the cultivation in the various media showed a positive effect for the production of kasugamycin.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.11a
• /
• pp.332-333
• /
• 2006

The properties of a cable Insulate capacity between surfaces with the variation of the interfacial breakdown, the addition of silicon oil, the variation of pressure and interfacial roughness were investigated. The Insulate trouble of a power cable is out of the interfacial parts, which breakdown the insulate breakdown capacity in a power cable. In this study, the analysis of electric field and the phenomenon of interfacial breakdown were reported by varying the surfaces condition of silicon rubber, XLPE used for connection materials of a power cable.

• Tribology and Lubricants
• /
• v.25 no.3
• /
• pp.176-181
• /
• 2009

Aminated polyacrylonitrile as the new organic disperse phases of the anhydrous ER fluid has been synthesized and ER effect of the suspension composed of aminated polyacrylonitrile in silicone oil investigated. The suspension showed a typical ER response (Bingham flow behavior) upon application of an electric field. The shear stress for the suspension exhibited the dependence with a factor equals to 1.6 power on theelectric field. The current density and the conductivity of the of aminated polyacrylonitrile suspension increase with the electric field intensity and moreover the conductivity of the suspension is about 8 order of magnitude higher than that of the silicone oil. On the basis of the the results, aminated polyacrylonitrile suspension showed the ER flow behavior upon application of the electric field due to the polarizability of the branched amine polar group of the aminated polyacrylonitrile particles.