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.

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.

scholarly journals Influence of Electric Fields on the Flow of a Liquid Crystal Mixture in Circular-Pipe Electrodes

2005 ◽  
Vol 48 (3) ◽  
pp. 517-523 ◽  
Author(s):  
Tetsuhiro TSUKIJI ◽  
Eitaro KOYABU ◽  
Tomohiro TSUJI ◽  
Shigeomi CHONO
Keyword(s):  
Liquid Crystal ◽  
Electric Fields ◽  
Circular Pipe ◽  
Crystal Mixture

Influence of electric fields in the flow of a liquid crystal mixture in circular pipe electrodes

2004 ◽  
Vol 2004 (0) ◽  
pp. 69
Author(s):  
Tetsuhiro TSUKIJI ◽  
Eitarou KOYABU ◽  
Tomohiro TSUJI ◽  
Shigeomi CHONO
Keyword(s):  
Liquid Crystal ◽  
Electric Fields ◽  
Circular Pipe ◽  
Crystal Mixture

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

Nozzle Flow Rate, Pressure Drop, and Response Time of Pulse Width Modulation (PWM) Nozzle Control Systems

2021 ◽  
Vol 64 (5) ◽  
pp. 1519-1532
Author(s):  
Jonathan Fabula ◽  
Ajay Sharda ◽  
Qing Kang ◽  
Daniel Flippo
Keyword(s):  
Pressure Drop ◽  
Response Time ◽  
Control Systems ◽  
Flow Rate ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Application Rate ◽  
Application Rates ◽  
Duty Cycles ◽  
Nozzle Pressure

HighlightsNozzle pressure drop varies between PWM systems at different application rates and application pressures.Change in flow rate with respect to the expected flow differs between PWM systems at different rates and pressures.There was a latency before the system reached the target application pressure.PWM systems operate for less time than the specified duty cycle, which may cause application errors.Abstract. Three PWM nozzle control systems, Capstan PinPoint II, John Deere ExactApply, and Raven Hawkeye, referred to as systems S1, S2, and S3, respectively, were used in this study. Data on nozzle pressure, boom pressure, flow rate, and response time were recorded with different duty cycles (25%, 50%, 75%, and 100%) and operating frequencies (10, 15, and 30 Hz) for two application rates (112.2 and 187.1 L ha-1) and two application pressures (275.8 and 448.2 kPa) at 1 kHz using a LabVIEW program and a cRIO data acquisition system. Results indicated that the PWM systems perform differently when operating at different application rates, pressures, duty cycles, and frequencies. Each PWM system provided a different pressure drop at the nozzle during operation. The increase in application rate and pressure increased the pressure drop. The percent change in flow rate with respect to the expected flow was also significantly different between the PWM systems, which could be due to the differences in pressure provided at the nozzle during operation. The PWM systems also showed latency before reaching the target application pressure during operation and operated for less time than the specified duty cycle at stable target pressure while also continuing to spray even after the solenoid valves had closed. The application pressure during peak and fall times and the time of stable application pressure within a cycle should be given careful consideration when selecting a PWM system, as they can contribute to application errors. Producers should also consider the pressure drop with the selected PWM system and target application rate to set up the system to apply at the desired pressure. Manufacturers mostly recommend operating PWM systems at 10 Hz. For the purpose of this study, the operating frequency of the PWM systems was set to 10 and 15 Hz for S1, to 15 and 30 Hz for S2, and to 10, 15, and 30 Hz for S3. Producers should expect differences in pressure drop, stabilized pressure application time, and flow rate if they choose to operate at a higher frequency. The results of this study are only applicable to the types of nozzle bodies and nozzle tips used. The data will differ based on the dual-orifice valve coefficient equation: the larger the second orifice, the greater the pressure drop. This will affect the final orifice pressure, as well as the flow rate. This study did not address the impact of flow resistance caused by differences in the design of nozzle bodies and nozzle types. Keywords: Nozzle flow rate, Pressure drop, Pulse width modulation control modules, Response time.

Pressure Drop Measurements for Air Flow Through Open-Cell Aluminum Foam

2004 ◽  
Author(s):  
Nihad Dukhan ◽  
Angel Alvarez
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Flow Rate ◽  
Aluminum Foam ◽  
Flow Direction ◽  
The Other ◽  
Turbulent Regime ◽  
Thick Sample ◽  
Open Cell ◽  
Two Samples

Wind-tunnel pressure drop measurements for airflow through two samples of forty-pore-per-inch commercially available open-cell aluminum foam were undertaken. Each sample’s cross-sectional area perpendicular to the flow direction measured 10.16 cm by 24.13 cm. The thickness in the flow direction was 10.16 cm for one sample and 5.08 cm for the other. The flow rate ranged from 0.016 to 0.101 m3/s for the thick sample and from 0.025 to 0.134 m3/s for the other. The data were all in the fully turbulent regime. The pressure drop for both samples increased with increasing flow rate and followed a quadratic behavior. The permeability and the inertia coefficient showed some scatter with average values of 4.6 × 10−8 m2 and 2.9 × 10−8 m2, and 0.086 and 0.066 for the thick and the thin samples, respectively. The friction factor decayed with the Reynolds number and was weakly dependent on the Reynolds number for Reynolds number greater than 35.

scholarly journals Implementation of 10-Bit Phase Modulation for Phase-Only LCOS Devices Using Deep Learning

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yuan Tong ◽  
Mike Pivnenko ◽  
Daping Chu
Keyword(s):  
Deep Learning ◽  
Liquid Crystal ◽  
Phase Modulation ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Spatial Information ◽  
Learning Model ◽  
High Definition ◽  
Liquid Crystal On Silicon ◽  
Deep Learning Model

A deep learning model was built to optimize the phase flicker performance for given pulse width modulation (PWM) driving patterns of a liquid crystal on silicon (LCOS) device. 10-bit phase modulation was physically realized with a phase flicker of 0.055% over 1024 addressed phase levels in respect to the total modulation range of 2π and a separation probability of 62.63% for the phase to stay within its level without overlapping with the adjacent ones. The spatial information bandwidth of the full high-definition (HD) LCOS device at 100 Hz was improved by 25%, from ~1.6 Gb/sec to ~2 Gb/sec.

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