Pressure drop of a liquid crystal mixture flowing in a circular tube with electrode surface

2003 ◽  
Vol 2003.2 (0) ◽  
pp. 263-264
Author(s):  
Tetsuhiro TSUKIJI ◽  
Tsuyoshi MITANI
Keyword(s):  
Liquid Crystal ◽  
Pressure Drop ◽  
Electrode Surface ◽  
Circular Tube ◽  
Crystal Mixture

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.

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.

Pressure drop of a liquid crystal mixture in a circular pipe electrode

2004 ◽  
Vol 2004.2 (0) ◽  
pp. 201-202
Author(s):  
Tetsuhiro TSUKIJI ◽  
Eitaro KOYABU ◽  
Keisuke NAKAYAMA ◽  
Tsuyoshi MITANI
Keyword(s):  
Liquid Crystal ◽  
Pressure Drop ◽  
Circular Pipe ◽  
Crystal Mixture

FLOW CHARACTERISTICS OF A LIQUID CRYSTAL MIXTURE IN A CIRCULAR PIPE ELECTRODE

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1346-1352
Author(s):  
TETSUHIRO TSUKIJI ◽  
EITARO KOYABU
Keyword(s):  
Liquid Crystal ◽  
Pressure Drop ◽  
Electric Fields ◽  
Flow Rate ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Flow Direction ◽  
Flow Analysis ◽  
Circular Pipe ◽  
Crystal Mixture

A circular pipe electrode was developed to control the pressure and the flow rate of the ER(Electro-rheological) fluids by one of the authors. The shape of the electrode is a circular pipe and some parts of the inner surface of the pipe are the electrode. The diameter of the tube is 1mm and the four pairs of the electrode are used. In the present study a liquid crystal mixture is selected for a homogeneous ER fluid and the pressure drop of the circular pipe electrode is measured for the constant flow rates under application of the voltages. The voltages are added in the peripheral direction. The director which is the average direction of the molecular of the liquid crystal is perpendicular to the flow direction. On the other hands, numerical analysis of the electric fields and the flow in the circular pipe electrode is conducted and the relations between the flow rate and the pressure are obtained for various electric field intensities, which almost agree with experimental results. The emphasized point of the present flow analysis is assuming that the viscosity of a liquid crystal mixture distributes in the flow field. Furthermore the pulse-wave voltages are added to the electrodes to control the pressure drop using the pulse width modulation. It is found that the pressure can be controlled using the pulse width modulation in the some range of the parameters.

Self-Regulation of Infrared Using a Liquid Crystal Mixture Doped with Push–Pull Azobenzene for Energy-Saving Smart Windows

2021 ◽  
Vol 13 (4) ◽  
pp. 5028-5033
Author(s):  
Seung-Won Oh ◽  
Seung-Min Nam ◽  
Sang-Hyeok Kim ◽  
Tae-Hoon Yoon ◽  
Wook Sung Kim
Keyword(s):  
Liquid Crystal ◽  
Energy Saving ◽  
Self Regulation ◽  
Smart Windows ◽  
Crystal Mixture

scholarly journals Design and Realization of a Compact Efficient Beam Combiner, Based on Liquid Crystal Pancharatnam–Berry Phase Gratings

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 220
Author(s):  
Boxuan Gao ◽  
Jeroen Beeckman ◽  
Kristiaan Neyts
Keyword(s):  
Liquid Crystal ◽  
Berry Phase ◽  
Polarized Light ◽  
Laser Beams ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Beam Combiner ◽  
High Diffraction Efficiency ◽  
High Diffraction ◽  
Crystal Mixture

We demonstrate a laser beam combiner based on four photo-patterned Pancharatnam–Berry (PB) phase gratings, which is compact and has high diffraction efficiency for incident circularly polarized light. The nematic liquid crystal mixture E7 is used as anisotropic material, and the thickness of the layer is controlled by spacers. The beam combiner can bring two parallel laser beams closer to each other while remaining parallel. This work shows the potential to realize components based on flat optical LC devices.

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