scholarly journals Optical measurement of liquid film thickness and wave velocity in liquid film flows

1996 ◽  
Vol 21 (5) ◽  
pp. 357-362 ◽  
Author(s):  
E. T. Hurlburt ◽  
T. A. Newell
Keyword(s):  
Film Thickness ◽  
Liquid Film ◽  
Wave Velocity ◽  
Optical Measurement ◽  
Liquid Film Thickness ◽  
Film Flows

Fluorescence and Fiber-Optics Based Real-Time Thickness Sensor for Dynamic Liquid Films

2009 ◽  
Vol 132 (3) ◽  
Author(s):  
T. W. Ng ◽  
A. Narain ◽  
M. T. Kivisalu
Keyword(s):  
Film Thickness ◽  
Liquid Film ◽  
Fiber Optics ◽  
Calibration Procedure ◽  
Liquid Films ◽  
Flow Dynamics ◽  
Liquid Film Thickness ◽  
Fiber Optic Technology ◽  
Thickness Measurements ◽  
Film Flows

To overcome the limitations/disadvantages of many known liquid film thickness sensing devices (viz. conductivity probes, reflectance based fiber-optics probes, capacitance probes, etc.), a new liquid film thickness sensor that utilizes fluorescence phenomena and fiber-optic technology has been developed and reported here. Measurements from this sensor are expected to facilitate better understanding of liquid film dynamics in various adiabatic, evaporating, and condensing film flows. The sensor accurately measures the instantaneous thickness of a dynamically changing liquid film in such a way that the probe does not perturb the flow dynamics in the proximity of the probe’s tip. This is achieved by having the probe’s exposed surface embedded flush with the surface over which the liquid film flows, and by making arrangements for processing the signals associated with the emission and collection of light (in distinctly different wavelength windows) at the probe’s flush surface. Instantaneous film thickness in the range of 0.5–3.0 mm can accurately (with a resolution that is within ±0.09 mm over 0.5–1.5 mm range and within ±0.18 mm over 1.5–3.0 mm range) be measured by the sensor described in this paper. Although this paper only demonstrates the sensor’s ability for dynamic film thickness measurements carried out for a doped liquid called FC-72 (perfluorohexane or C6F14 from 3M Corporation, Minneapolis, MN), the approach and development/calibration procedure described here can be extended, under similar circumstances, to some other liquid films and other thickness ranges as well.

Fluorescence and Fiber-Optics Based Real-Time Thickness Sensor for Dynamic Liquid Films

2007 ◽  
Author(s):  
T. W. Ng ◽  
A. Narain
Keyword(s):  
Film Thickness ◽  
Liquid Film ◽  
Fiber Optics ◽  
Calibration Procedure ◽  
Liquid Films ◽  
Flow Dynamics ◽  
Liquid Film Thickness ◽  
Fiber Optic Technology ◽  
Thickness Measurements ◽  
Film Flows

To overcome the limitations/disadvantages of many known liquid film thickness sensing devices (viz. conductivity probes, reflectance based fiber-optics probes, capacitance probes, etc.), a new liquid film thickness sensor that utilizes fluorescence phenomena and fiber-optic technology has been developed and reported here. Measurements from this sensor are expected to facilitate better understanding of liquid film dynamics in various adiabatic, evaporating, and condensing film flows. The sensor accurately measures the instantaneous thickness of a dynamically changing liquid film in such a way that the probe does not perturb the flow dynamics in the proximity of the probe’s tip. This is achieved by having the probe’s exposed surface embedded flush with the surface over which the liquid film flows, and by making arrangements for processing the signals associated with the emission and collection of light (in distinctly different wavelength windows) at the probe’s flush surface. Instantaneous film thickness in the range of 0.5 to 3.0 mm can accurately (with a resolution that is within +/− 0.09 mm over 0.5 to 1.5 mm range and within +/− 0.18 mm over 1.5 to 3.0 mm range) be measured by the sensor described in this paper. Although this paper only demonstrates the sensor’s ability for dynamic film thickness measurements carried out for a doped liquid called FC-72 (perfluorohexane or C6F14 from 3M Corporation), the approach and development/calibration procedure described here can be extended, under similar circumstances, to some other liquid films as well.

Study on Liquid Film Thickness of Accelerated Slug Flow in Micro Tubes

2014 ◽  
Author(s):  
Kenshiro Muramatsu ◽  
Youngjik Youn ◽  
Youngbae Han ◽  
Keishi Yokoyama ◽  
Yosuke Hasegawa ◽  
...  
Keyword(s):  
Film Thickness ◽  
Liquid Film ◽  
Slug Flow ◽  
Liquid Film Thickness

Experimental comparison of the spray atomization of heavy and light fuel oil at different temperatures and pressures for pressure-swirl injector

2021 ◽  
pp. 095765092199437
Author(s):  
Elyas Rostami ◽  
Hossein Mahdavy Moghaddam
Keyword(s):  
Film Thickness ◽  
Liquid Film ◽  
Diesel Fuel ◽  
Temperature Increase ◽  
Liquid Film Thickness ◽  
Fuel Oil ◽  
Spray Angle ◽  
Breakup Length ◽  
Fuel Atomization ◽  
Mean Diameter

In this study, the atomization of heavy fuel oil (Mazut) and diesel fuel at different pressures is compared experimentally. Also, the effects of temperature on the Mazut fuel atomization are investigated experimentally. Mass flow rate, discharge coefficient, wavelength, liquid film thickness, ligament diameter, spray angle, breakup length, and sature mean diameter are obtained for the Mazut and diesel fuel. Fuels spray images at different pressures and temperatures are recorded using the shadowgraphy method and analyzed by the image processing technique. Error analysis is performed for the experiments, and the percentage of uncertainty for each parameter is reported. The experimental results are compared with the theoretical results. Also, Curves are proposed and plotted to predict changes in the behavior of atomization parameters. Diesel fuel has less viscosity than Mazut fuel. Diesel fuel has shorter breakup length, wavelength, liquid film thickness, and sature mean diameter than Mazut fuel at the same pressure. Diesel fuel has a larger spray angle and a larger discharge coefficient than Mazut fuel at the same pressure. As the pressure and temperature increase, fuel atomization improves. The viscosity of Mazut fuel is decreased by temperature increase. As the fuel injection pressure and temperature increase, breakup length, wavelength, liquid film thickness, and sature mean diameter decrease; also, spray angle increases.

Measurement of Liquid Film Thickness in Micro Tube Annular Flow

2010 ◽  
Author(s):  
Hiroshi Kanno ◽  
Youngbae Han ◽  
Yusuke Saito ◽  
Naoki Shikazono
Keyword(s):  
Heat Transfer ◽  
Film Thickness ◽  
Liquid Film ◽  
Annular Flow ◽  
Liquid Film Thickness ◽  
Phase Flow ◽  
Two Phase ◽  
Micro Scale ◽  
Film Model ◽  
Annular Film

Heat transfer in micro scale two-phase flow attracts large attention since it can achieve large heat transfer area per density. At high quality, annular flow becomes one of the major flow regimes in micro two-phase flow. Heat is transferred by evaporation or condensation of the liquid film, which are the dominant mechanisms of micro scale heat transfer. Therefore, liquid film thickness is one of the most important parameters in modeling the phenomena. In macro tubes, large numbers of researches have been conducted to investigate the liquid film thickness. However, in micro tubes, quantitative information for the annular liquid film thickness is still limited. In the present study, annular liquid film thickness is measured using a confocal method, which is used in the previous study [1, 2]. Glass tubes with inner diameters of 0.3, 0.5 and 1.0 mm are used. Degassed water and FC40 are used as working fluids, and the total mass flux is varied from G = 100 to 500 kg/m2s. Liquid film thickness is measured by laser confocal displacement meter (LCDM), and the liquid-gas interface profile is observed by a high-speed camera. Mean liquid film thickness is then plotted against quality for different flow rates and tube diameters. Mean thickness data is compared with the smooth annular film model of Revellin et al. [3]. Annular film model predictions overestimated the experimental values especially at low quality. It is considered that this overestimation is attributed to the disturbances caused by the interface ripples.

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