scholarly journals Simultaneous measurements of thickness and local mass transfer rate on falling liquid films.

1979 ◽  
Vol 12 (6) ◽  
pp. 483-485
Author(s):  
RYUZO ITO ◽  
KAORU TOMURA ◽  
MASAO YAMAMOTO ◽  
YUKIE OKADA ◽  
NOBUHIRO TSUBOI ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
Liquid Films ◽  
Local Mass ◽  
Simultaneous Measurements ◽  
Local Mass Transfer ◽  
Falling Liquid Films

The Visualisation of Mass Transfer Rate Around a Sphere

1964 ◽  
Vol 68 (638) ◽  
pp. 137-139 ◽  
Author(s):  
K. Lee ◽  
H. Barrow ◽  
D. J. Ryley
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Large Scale ◽  
Mass Transfer Rate ◽  
Droplet Surface ◽  
Scale Model ◽  
Flow Visualisation ◽  
Local Mass ◽  
Large Scale Model ◽  
Local Mass Transfer

The purpose of this note is to report the results of an experimental investigation which was conducted to permit the local mass transfer rate around a sphere to be visualised. The present problem of mass transfer from a sphere had its origin in a study of the evaporation of a water droplet in a superheated steam atmosphere. Because of the small physical size of the droplet and the difficulty of measuring local mass transfer rates from the droplet surface, it was necessary to employ a large scale model to study local transfer rate around a sphere. It was considered that flow visualisation would afford at least a qualitative result of local mass transfer rate. In fluid mechanics studies, the flow visualisation techniques are well known. Such methods include the use of smoke filaments, tufts, or chemical coatings and so forth to provide information about the state of boundary layer over a solid surface, fluid particle paths and state of flow.

Experimental Investigations of Couette-Taylor-Poiseuille Flows Using the Electro-Diffusional Technique

2016 ◽  
Author(s):  
Emna Berrich ◽  
Fethi Aloui ◽  
Jack Legrand
Keyword(s):  
Mass Transfer ◽  
Shear Rate ◽  
Mass Transfer Rate ◽  
Axial Flow ◽  
Reynolds Numbers ◽  
Wall Shear Rate ◽  
Experimental Investigations ◽  
Local Mass ◽  
Local Mass Transfer ◽  
Wall Shear

Couette-Taylor-Poiseuille flow CTPF consists on the superposition of Couette-Taylor flow to an axial flow. The CTPF flow hydrodynamics studies remain rather qualitative or numerical or are restricted to relatively low Taylor and/or axial Reynolds numbers. For more comprehensive and control of CTPF, especially for relatively high Taylor numbers and high axial Reynolds numbers, we investigated experimentally CTF with and without an axial flow, using the electro-diffusion ED method. This technique requires the use of Electro-Diffusion ED probe which allows the determination of the local mass transfer rate from the Limiting Diffusion current measurement delivered by the ED probe while it is polarized by a polarization voltage. From the local mass transfer (the Sherwood number), we determined the wall shear rate using different approaches. The results illustrate that low axial flow can generate a stabilizing effect on the CT flow. The time-evolutions of the local mass transfer and the wall shear rate are periodic. These evolutions characterize the waviness or the stretching of the vortices. However, Taylor Wavy Vortex Flow TWVF is destabilized under the effect of relatively important axial flow. The time-evolutions of wall shear rate are no longer periodic. Indeed, Taylor vortices are overlapped or completely destructed.

Measurement of Local Mass Transfer and the Resulting Roughness in a Large Diameter S-Bend at High Reynolds Number

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
D. Wang ◽  
D. Ewing ◽  
T. Le ◽  
C. Y. Ching
Keyword(s):  
Mass Transfer ◽  
Reynolds Number ◽  
Mass Transfer Rate ◽  
Large Diameter ◽  
Reynolds Numbers ◽  
High Mass ◽  
Local Mass ◽  
Roughness Elements ◽  
Local Mass Transfer ◽  
High Reynolds

The local mass transfer and the resulting roughness in a 203 mm diameter back-to-back bend arranged in an S-configuration were measured at a Reynolds number of 300,000. A dissolving wall method using gypsum dissolution to water at 40 °C was used, with a Schmidt number of 660. The topography of the unworn and worn inner surface was quantified using nondestructive X-ray computed tomography (CT) scans. The local mass transfer rate was obtained from the local change in radius over the flow time. Two regions of high mass transfer were present: (i) along the intrados of the first bend near the inlet and (ii) at the exit of the extrados of the first bend that extends to the intrados of the second bend. The latter was the region of highest mass transfer, and the scaling of the maximum Sherwood number with Reynolds number followed that developed for lower Reynolds numbers. The relative roughness distribution in the bend corresponded to the mass transfer distribution, with higher roughness in the higher mass transfer regions. The spacing of the roughness elements in the upstream pipe and in the two regions of high mass transfer was approximately the same; however, the spacing-to-height ratio was very different with values of 20, 10, and 6, respectively.

Measurement of Local Mass Transfer Distribution in a Large Diameter S-Bend at High Reynolds Number

2014 ◽  
Author(s):  
D. Wang ◽  
D. Ewing ◽  
T. Le ◽  
C. Y. Ching
Keyword(s):  
Mass Transfer ◽  
Reynolds Number ◽  
Mass Transfer Rate ◽  
Large Diameter ◽  
High Mass ◽  
Flow Loop ◽  
Local Mass ◽  
Common Coordinate System ◽  
Local Mass Transfer ◽  
High Reynolds

The local mass transfer in a 203mm diameter back to back bend arranged in a S-configuration was measured at a Reynolds number of 300,000. A dissolving wall method using gypsum dissolution to water at 40°C was used, with a Schmidt number of 660. The experiment was performed in a flow loop by flowing water through the test section. The topography of the unworn and the worn inner surface was quantified using nondestructive X-ray Computed Tomography (CT) scans. The two scanned surfaces were aligned to a common coordinate system using commercial software and in-house routines. The local mass transfer rate was obtained from the local change in radius over the flow time. Two regions of high mass transfer were present: (i) along the intrados of the first bend near the inlet and (ii) at the exit of the extrados of the first bend that extends to the intrados of the second bend. The latter was the region of highest mass transfer in the S-bend.

Free Convective Mass Transfer at Isosceles Triangular Surfaces of Varying Inclination

2003 ◽  
Vol 68 (11) ◽  
pp. 2080-2092 ◽  
Author(s):  
Martin Keppert ◽  
Josef Krýsa ◽  
Anthony A. Wragg
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
Mass Transfer Process ◽  
Sulfate Solution ◽  
Convective Mass Transfer ◽  
Varying Length ◽  
Inclined Surface ◽  
Vertical Case ◽  
Limiting Diffusion Current

The limiting diffusion current technique was used for investigation of free convective mass transfer at down-pointing up-facing isosceles triangular surfaces of varying length and inclination. As the mass transfer process, copper deposition from acidified copper(II) sulfate solution was used. It was found that the mass transfer rate increases with inclination from the vertical to the horizontal position and decreases with length of inclined surface. Correlation equations for 7 angles from 0 to 90° were found. The exponent in the ShL-RaL correlation ranged from 0.247 for the vertical case, indicating laminar flow, to 0.32 for inclinations of 60 to 90°, indicating mixed or turbulent flow. The general correlation ShL = 0.358(RaL sin θ)0.30 for the RaL sin θ range from 7 × 106 to 2 × 1011 and inclination range from 15 to 90° was obtained.

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