Pressure Drop of Liquid Crystal Flowing Between Two Parallel-Plate Electrodes

2001 ◽  
Author(s):  
Tetsuhiro Tsukiji ◽  
Shinsuke Tanabe
Keyword(s):  
Liquid Crystal ◽  
Pressure Drop ◽  
Parallel Plate ◽  
High Speed ◽  
Time History ◽  
Video Camera ◽  
Open Loop ◽  
Test Facility ◽  
Flow Rates ◽  
Temperature Constant

Abstract Liquid crystal is one of homogeneous ER (Electrorheological) fluids in some range of temperature. Transient responses of pressure drop are examined when liquid crystal flows between two parallel-plate electrodes for constant flow rates. When voltages are applied on the liquid crystal and removed, the pressure responses of the inlet of electrodes are measured with the pressure transducer. At the same time, liquid crystal between the transparent electrodes made of glass is visualized with the high-speed video camera to investigate the time history of the director of the liquid crystal. Outlet of the flow channel with two parallel-plate electrodes is atmosphere. Relation between the flow visualization results and changes of pressure drop is investigated especially for transient period. In the present experiment the flow rates change from 0.001cc/sec (velocity is 1mm/sec) to 0.003cc/sec and the electric field intensity is from 0.2kV/mm to 1kV/mm. The gap of the electrodes is 0.2mm. The isotropic-nematic transition is 35.5°C and smectic-nematic transition is 23.1°C. The open-loop test facility with the liquid crystal is set in a pyrostat to keep the temperature constant.

ER EFFECT OF LIQUID CRYSTAL FLOWING BETWEEN TWO PARALLEL-PLATE ELECTRODES

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2569-2575 ◽  
Author(s):  
TETSUHIRO TSUKIJI ◽  
SHINSUKE TANABE
Keyword(s):  
Liquid Crystal ◽  
Pressure Drop ◽  
Parallel Plate ◽  
High Speed ◽  
Time History ◽  
Video Camera ◽  
Open Loop ◽  
Test Facility ◽  
Flow Rates ◽  
Temperature Constant

Liquid crystal is one of homogeneous ER(Electro-rheological) fluids in some range of temperature. Transient responses of pressure drop are examined when liquid crystal flows between two parallel-plate electrodes for constant flow rates. When voltages are applied on the liquid crystal and removed, the pressure responses of the inlet of electrodes are measured with the pressure transducer. At the same time, liquid crystal between the transparent electrodes made of glass is visualized with the high-speed video camera to investigate the time history of the director of the liquid crystal. Outlet of the flow channel with two parallel-plate electrodes is atmosphere. Relation between the flow visualization results and the changes of pressure drop is investigated especially for transient period. In the present experiment the flow rates change from 0.001 cc/sec(velocity is 1 mm/sec) to 0.003 cc/sec and the electric field intensity is from 0.2 kV/mm to 1 kV/mm. The gap of the electrodes is 0.2 mm. The isotropic-nematic transition is 35.5°C and smectic-nematic transition is 23.1°C. The open-loop test facility with the liquid crystal is set in a pyrostat to keep the temperature constant.

Influence of Electric Fields on Pressure Drop of Liquid Crystal Mixture

2002 ◽  
Author(s):  
Tetsuhiro Tsukiji ◽  
Tsuyoshi Mitani
Keyword(s):  
Liquid Crystal ◽  
Pressure Drop ◽  
Electric Fields ◽  
Parallel Plate ◽  
Time History ◽  
Open Loop ◽  
Test Facility ◽  
Pulse Frequency Modulation ◽  
Flow Rates ◽  
Crystal Mixture

Liquid crystal is one of homogeneous ER (Electrorheological) fluids in some range of temperature. In the present experiment a liquid crystal mixture is used. The responses of the pressure drop are examined when the liquid crystal mixture flows between two parallel-plate electrodes for the constant flow rates. When the voltages are applied on the liquid crystal mixture and removed, the pressure responses of the inlet electrodes are measured with the pressure transducer. At same time, the liquid crystal mixture between the transparent electrodes made of glass is visualized with the video camera investigate the time history of the director of the liquid crystal mixture. The AC voltages are also used to investigate dependence of the liquid crystal mixture on the frequency the voltages. Outlet of the flow channel with two parallel-plate electrodes is atmosphere. Relation between the flow visualization results and the changes of pressure drop investigated especially for transient period. On the other hand, the pulse-wave voltages are added to the electrodes to control the pressure drop using the pulse width modulation or the pulse frequency modulation. In the present study the flow rates change from 0.001cc/sec (velocity is lmm/sec) to 0.003cc/sec and the electric field intensity is from 0.2kV/mm to lkV/mm. The gap of the electrodes is 0.2mm.The isotropic-nematic transition is 90.0°C and smectic-nematic transition is −44.0°C for the liquid crystal mixture. The open-loop test facility the liquid crystal is set in a pyrostat to keep the temperature constant.

Influence of Electric Fields on Flow of Liquid Crystal Mixture in a Circular Tube With Electrode Surface

2003 ◽  
Author(s):  
Tetsuhiro Tsukiji ◽  
Tsuyoshi Mitani
Keyword(s):  
Liquid Crystal ◽  
Pressure Drop ◽  
Electric Fields ◽  
Pulse Width Modulation ◽  
Circular Tube ◽  
Pulse Frequency ◽  
Open Loop ◽  
Test Facility ◽  
Pulse Frequency Modulation ◽  
Crystal Mixture

Liquid crystal is one of functional fluids to control an apparent viscosity using an electric field intensity. It is also called ER (Electro-rheological) fluids. In the present experiment a liquid crystal mixture made of some kinds of the nematic liquid crystal is used. The responses of the pressure drop are examined when the liquid crystal mixture flows in a circular tube with the electrode walls on some parts of the inner surface of the tube for the constant flow rates. The four pair of the electrode is used and the voltages are added in the peripheral direction. When the voltages are applied on the liquid crystal mixture and removed, the pressure responses of the inlet of the circular tube are measured with the pressure transducer. On the other hand, the pulse-wave voltages are added to the electrodes to control the pressure drop using the pulse width modulation or the pulse frequency modulation. The diameter of the circular tube is 1.0mm. The isotropic-nematic transition is 90.0°C and smectic-nematic transition is −44.0°C for the liquid crystal mixture. The open-loop test facility with the liquid crystal mixture is set in a pyrostat to keep the temperature constant.

Pressure Response of ER Fluids between Two Parallel-Plate Electrodes

1999 ◽  
Vol 13 (14n16) ◽  
pp. 1917-1924 ◽  
Author(s):  
Tetsuhiro Tsukiji ◽  
Ken-Ichi Hori
Keyword(s):  
Pressure Drop ◽  
Electric Fields ◽  
Parallel Plate ◽  
High Speed ◽  
Silicone Oil ◽  
Excitation Frequency ◽  
Video Camera ◽  
Sine Wave ◽  
High Speed Video Camera ◽  
Er Fluids

The frequency response of the pressure drop of the ER fluids between two parallel-plate electrodes to sine-wave changes in the applied electric field is investigated for constant flow rates. The electrodes gap is set at 2mm. The ER fluids used in the present study consist of cellulose suspended in silicone oil. Unipolar and bipolar sinusoidal electric fields, and constant ones are used. The frequency of the electric fields is changed from 0.1 to 1000Hz. The averages and the amplitudes of the pressure drop are measured. Dependence of the pressure drop on electrical excitation frequency is investigated. Furthermore the microscopic behavior of ER suspension structure between two fixed electrodes is visualized for the flowing ER fluids with high speed video camera under application of the electric fields. The effect of electrical change on the pressure drop is discussed from the results of the flow visualization.

scholarly journals Detonation effects of shallow buried explosive in sandy soil on target plate acceleration in a small-scale blast test

2018 ◽  
Vol 192 ◽  
pp. 02028
Author(s):  
Hassan Zulkifli Abu ◽  
Ibrahim Aniza ◽  
Mohamad Nor Norazman
Keyword(s):  
Sandy Soil ◽  
High Speed ◽  
Early Stage ◽  
Time History ◽  
Video Camera ◽  
Small Scale ◽  
Target Plate ◽  
Air Blast ◽  
High Speed Video Camera ◽  
The Impact

Small-scale blast tests were carried out to observe and measure the influence of sandy soil towards explosive blast intensity. The tests were to simulate blast impact imparted by anti-vehicular landmine to a lightweight armoured vehicle (LAV). Time of occurrence of the three phases of detonation phase in soil with respect to upward translation time of the test apparatus were recorded using high-speed video camera. At the same time the target plate acceleration was measured using shock accelerometer. It was observed that target plate deformation took place at early stage of the detonation phase before the apparatus moved vertically upwards. Previous data of acceleration-time history and velocity-time history from air blast detonation were compared. It was observed that effects of soil funnelling on blast wave together with the impact from soil ejecta may have contributed to higher blast intensity that characterized detonation in soil, where detonation in soil demonstrated higher plate velocity compared to what occurred in air blast detonation.

Pressure Drop Prediction Considered Fluidized Particle in Vertical Plug Transportation

2007 ◽  
Author(s):  
Kenji Kofu ◽  
Mitsuaki Ochi ◽  
Masahiro Takei
Keyword(s):  
Pressure Drop ◽  
Particle Velocity ◽  
High Speed ◽  
Video Camera ◽  
Two Phase ◽  
Phase Theory ◽  
Digital Video Camera ◽  
Fluidized Particle ◽  
Experimental Values ◽  
Fluidized Particles

The prediction equations on particle velocity within a plug and pressure drop in vertical pipe have been formulated by considering fluidized particles. The gas-liquid two-phase theory established by Davidson and Harrison has been assumed as fluidized particles. As a result, the all kinds of calculated values on particle velocity and pressure drop are in good agreement with the experimental values while internal pipe diameter and kinds of particles are changed. The error between calculations and experiments is almost within ± 10%. Additionally, the plug velocity and particle velocity in the flow and radius directions have been measured by digital video camera, high speed camera and PIV. As a result, gas-liquid two-phase theory can be applied to the relation between plug velocity and particle velocity, and there is no particle velocity distribution in the plug. In short, particles in the plug are fixed relative to each other and so they all move with the same velocity.

Bubble Departure and Convection in Large Aspect Ratio Microchannels

2006 ◽  
Author(s):  
David W. Fogg ◽  
Ching-Hsiang Cheng ◽  
Ken E. Goodson
Keyword(s):  
Pressure Drop ◽  
Aspect Ratio ◽  
High Speed ◽  
Imaging System ◽  
Time History ◽  
Heat Sinks ◽  
Scaling Analysis ◽  
Two Phase ◽  
Aspect Ratios ◽  
History Of

The growth and departure of vapor bubbles governs pressure drop and thermal resistance of two-phase microchannel heat sinks. Little data is available for the growth, departure, and convection of bubbles in microchannels. The current study uses isothermal air injection to simulate the nucleation and growth of bubbles in high aspect microchannels with Dh≈48μm and aspect ratios from 20 to 40 with 1 < ReH < 10. Liquid pressure drop and flow rate are measured during bubble growth along with the time history of the bubble geometry obtained from a high speed video imaging system at rates up to 50,000 frames per second. Bubble departure is found to vary linearly with aspect ratio divided by inlet Reynolds number, while the convection velocity depends on the normalized bubble width and normalized liquid film thickness. A scaling analysis identifies the increase in axial pressure drop due to bubble confinement as the driving force for both bubble departure and convection.

Scaling analysis of core pressure drop in reduced height integral test facility

Kerntechnik ◽  
2018 ◽  
Vol 83 (3) ◽  
pp. 178-180
Author(s):  
P. Ju ◽  
B. Long ◽  
L. Li ◽  
Q. Su ◽  
X. Wu ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Test Facility ◽  
Scaling Analysis ◽  
Integral Test ◽  
Reduced Height

The effect of two-phase flow regime on hydrodynamics and mass transfer in a horizontal-tube gas-liquid reactor

1985 ◽  
Vol 50 (3) ◽  
pp. 745-757 ◽  
Author(s):  
Andreas Zahn ◽  
Lothar Ebner ◽  
Kurt Winkler ◽  
Jan Kratochvíl ◽  
Jindřich Zahradník
Keyword(s):  
Mass Transfer ◽  
Pressure Drop ◽  
Flow Regime ◽  
Liquid Flow ◽  
Horizontal Tube ◽  
Liquid Holdup ◽  
Two Phase ◽  
Flow Rates ◽  
Type Relation ◽  
Good Agreement

The effect of two-phase flow regime on decisive hydrodynamic and mass transfer characteristics of horizontal-tube gas-liquid reactors (pressure drop, liquid holdup, kLaL) was determined in a cocurrent-flow experimental unit of the length 4.15 m and diameter 0.05 m with air-water system. An adjustable-height weir was installed in the separation chamber at the reactor outlet to simulate the effect of internal baffles on reactor hydrodynamics. Flow regime maps were developed in the whole range of experimental gas and liquid flow rates both for the weirless arrangement and for the weir height 0.05 m, the former being in good agreement with flow-pattern boundaries presented by Mandhane. In the whole range of experi-mental conditions pressure drop data could be well correlated as a function of gas and liquid flow rates by an empirical exponential-type relation with specific sets of coefficients obtained for individual flow regimes from experimental data. Good agreement was observed between values of pressure drop obtained for weirless arrangement and data calculated from the Lockhart-Martinelli correlation while the contribution of weir to the overall pressure drop was well described by a relation proposed for the pressure loss in closed-end tubes. In the region of negligible weir influence values of liquid holdup were again succesfully correlated by the Lockhart-Martinelli relation while the dependence of liquid holdup data on gas and liquid flow rates obtained under conditions of significant weir effect (i.e. at low flow rates of both phases) could be well described by an empirical exponential-type relation. Results of preliminary kLaL measurements confirmed the decisive effect of the rate of energy dissipation on the intensity of interfacial mass transfer in gas-liquid dispersions.

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