Moisture Fraction Measurements for Two-Phase Mist Flow Using High-Sensitivity Capacitance Sensors

1997 ◽  
Vol 117 (3) ◽  
pp. 353-365 ◽  
Author(s):  
Michael F. Dowling ◽  
Jason D. Wartell ◽  
Sheldon M. Jeter ◽  
Said I. Abdel-Khalik
Keyword(s):  
High Sensitivity ◽  
Two Phase ◽  
Mist Flow

Determination of specific interfacial areas in swirled two-phase flow

1983 ◽  
Vol 48 (3) ◽  
pp. 842-853
Author(s):  
Kurt Winkler ◽  
František Kaštánek ◽  
Jan Kratochvíl
Keyword(s):  
Interfacial Area ◽  
Liquid Volume ◽  
Upward Flow ◽  
Two Phase ◽  
Flow Rates ◽  
Mist Flow ◽  
Interfacial Areas ◽  
Correlation Parameters ◽  
Flow Components

Specific gas-liquid interfacial area in flow tubes 70 mm in diameter of the length 725 and 1 450 mm resp. containing various swirl bodies were measured for concurrent upward flow in the ranges of average gas (air) velocities 11 to 35 ms-1 and liquid flow rates 13 to 80 m3 m-2 h-1 using the method of CO2 absorption into NaOH solutions. Two different flow regimes were observed: slug flow swirled annular-mist flow. In the latter case the determination was carried out separately for the film and spray flow components, respectively. The obtained specific areas range between 500 to 20 000 m3 m-2. Correlation parameters are energy dissipation criteria, related to the geometrical reactor volume and to the static liquid volume in the reactor.

An Experimental Study of Mist/Air Film Cooling With Fan-Shaped Holes on an Extended Flat Plate—Part II: Two-Phase Flow Measurements and Droplet Dynamics

2017 ◽  
Vol 140 (4) ◽  
Author(s):  
Reda Ragab ◽  
Ting Wang
Keyword(s):  
Flow Behavior ◽  
Data Rate ◽  
Main Flow ◽  
Shear Stresses ◽  
Two Phase ◽  
Flow Measurements ◽  
Droplet Dynamics ◽  
Mist Flow ◽  
Film Layer ◽  
Upper Boundary

A phase Doppler particle analyzer (PDPA) system is employed to measure the two-phase mist flow behavior including flow velocity field, droplet size distribution, droplet dynamics, and turbulence characteristics. Based on the droplet measurements made through PDPA, a projected profile describing how the air–mist coolant jet flow spreads and eventually blends into the hot main flow is prescribed for both cylindrical and fan-shaped holes. The mist film layer consists of two layers: a typical coolant film layer (cooling air containing the majority of the droplets) and a wider droplet layer containing droplets outside the film layer. Thanks to the higher inertia possessed by larger droplets (>20 μm in diameter) at the injection hole, the larger droplets tend to shoot across the coolant film layer, resulting in a wider droplet layer than the coolant film layer. The wider droplet layer boundaries are detected by measuring the droplet data rate (droplet number per second) distribution, and it is identified by a wedge-shaped enclosure prescribed by the data rate distribution curve. The coolant film layer is prescribed by its core and its upper boundary. The apex of the data rate curve, depicted by the maximum data rate, roughly indicates the core region of the coolant film layer. The upper boundary of the coolant film layer, characterized by active mixing with the main flow, is found to be close to relatively high values of local Reynolds shear stresses. With the results of PDPA measurements and the prescribed coolant film and droplet layer profiles, the heat transfer results on the wall presented in Part I are re-examined, and the fundamental mist-flow physics are analyzed. The three-dimensional (3D) droplet measurements show that the droplets injected from the fan-shaped holes tend to spread wider in lateral direction than cylinder holes and accumulate at the location where the neighboring coolant film layers meet. This flow and droplet behavior explain the higher cooling performance as well as mist-enhancement occurs between the fan-shaped cooling holes, rather than along the hole's centerline as demonstrated in the case using the cylindrical holes.

Study on Velocity Measurement of Gas/Solid Flow Based on Electrostatic Sensor

2014 ◽  
Vol 614 ◽  
pp. 275-278
Author(s):  
Yu Tang ◽  
Xiang Deng ◽  
Shuo Tian
Keyword(s):  
Measurement System ◽  
Velocity Measurement ◽  
Flow Measurement ◽  
Cross Correlation ◽  
Low Cost ◽  
High Sensitivity ◽  
Two Phase ◽  
Solid Flow ◽  
Correlation Algorithm ◽  
Electrostatic Induction

Electrostatic sensor is based on the principle of electrostatic induction. It is widely used for gas/solid two-phase flow measurement because it has the advantages of simple structure, high sensitivity, low cost, etc. In this paper, a velocity measurement system of gas/solid flow based on electrostatic sensor and cross-correlation algorithm is discussed. Electrostatic sensor with circular electrode is adopted. By COMSOL optimum simulation, the axial length of the electrode is designed. The signal conditioning circuits are discussed and cross-correlation algorithm is analyzed. The initial experimental results demonstrate that the velocity measurement system of gas/solid flow designed in this paper is feasible.

A New Method of Fault Phase Identification for High Voltage Transmission Lines Based on the Fault Component of Phase Voltage

2013 ◽  
Vol 732-733 ◽  
pp. 1056-1064
Author(s):  
Yang Chen ◽  
Yan Hu ◽  
Neng Ling Tai
Keyword(s):  
Kalman Filter ◽  
High Voltage ◽  
Transmission Lines ◽  
High Sensitivity ◽  
New Method ◽  
Phase Identification ◽  
Phase Voltage ◽  
Two Phase ◽  
Kalman Filter Algorithm ◽  
High Voltage Transmission

Since the existing fault phase identification methods can not identify all fault types quickly and accurately for high voltage transmission lines, this article proposed a new method of fault phase identification based on the fault component of phase voltage difference and the kalman filter algorithm. The method defined the fault components ratio of one phase voltage to the difference of the other two phase voltages as a fault phase identification factor. By analyzing the characteristics of fault phase identification factors in each fault type, the fault phase can be identified. Simulation results show that using the kalman filter algorithm to extract fundamental component is faster and more accurate. Meanwhile, the method can identify fault phases within half a cycle and is scarcely influenced by fault resistances, fault locations and fault initial phase angles. It also has a high sensitivity when the fault is on the side of strong source.

Drag reduction in two-phase annular-mist flow of air and water

AIChE Journal ◽  
1976 ◽  
Vol 22 (3) ◽  
pp. 615-617 ◽  
Author(s):  
Nicholas D. Sylvester ◽  
James P. Brill
Keyword(s):  
Drag Reduction ◽  
Two Phase ◽  
Mist Flow

Vapor/Droplet Coupling and the Mist Flow (OTEC) Cycle

1983 ◽  
Vol 105 (2) ◽  
pp. 181-186 ◽  
Author(s):  
C. K. B. Lee ◽  
S. L. Ridgway
Keyword(s):  
Interaction Parameter ◽  
Liquid Fraction ◽  
Energy Coupling ◽  
Vapor Flow ◽  
Two Phase ◽  
Slip Ratio ◽  
Mist Flow ◽  
High Vapor ◽  
Ocean Thermal Energy ◽  
Momentum Coupling

The present experiments have demonstrated that water droplets (∼200-μm dia) can be lifted to substantial heights (∼50 m) by their own vapor produced in flashing over temperature differences typical of the tropical seas. The coupling between the vapor and droplets is found to be excellent. The efficiency for momentum coupling is over 90 percent, and that for energy coupling is shown to vary inversely with the slip ratio. For the conditions in the present experiments, it varies from 50 to 80 percent. The momentum transfer is correlated with an interaction parameter which is the product of the liquid fraction, the slip, and the amount of flashing. For the high vapor flow cases, the pressure difference across the lift column is found to be proportional to the interaction parameter. The relevance of the two-phase flow to a class of open-cycle ocean thermal energy conversion (OTEC) schemes is considered, and the implications of the observed strong vapor/droplet coupling to the feasibility of the mist-flow OTEC cycle are discussed.

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