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Laminar flow reactor

About: Laminar flow reactor is a(n) research topic. Over the lifetime, 2353 publication(s) have been published within this topic receiving 54801 citation(s).
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01 Aug 1969-

3,801 citations

Journal ArticleDOI
Abstract: Laser-Doppler measurements of velocity distribution and reattachment length are reported downstream of a single backward-facing step mounted in a two-dimensional channel. Results are presented for laminar, transitional and turbulent flow of air in a Reynolds-number range of 70 < Re < 8000. The experimental results show that the various flow regimes are characterized by typical variations of the separation length with Reynolds number. The reported laser-Doppler measurements do not only yield the expected primary zone of recirculating flow attached to the backward-facing step but also show additional regions of flow separation downstream of the step and on both sides of the channel test section. These additional separation regions have not been previously reported in the literature.Although the high aspect ratio of the test section (1:36) ensured that the oncoming flow was fully developed and two-dimensional, the experiments showed that the flow downstream of the step only remained two-dimensional at low and high Reynolds numbers.The present study also included numerical predictions of backward-facing step flow. The two-dimensional steady differential equations for conservation of mass and momentum were solved. Results are reported and are compared with experiments for those Reynolds numbers for which the flow maintained its two-dimensionality in the experiments. Under these circumstances, good agreement between experimental and numerical results is obtained.

1,550 citations

Journal ArticleDOI
Abstract: The equations describing the motion of a gas carrying small dust particles are given and the equations satisfied by small disturbances of a steady laminar flow are derived. The effect of the dust is described by two parameters; the concentration of dust and a relaxation time τ which measures the rate at which the velocity of a dust particle adjusts to changes in the gas velocity and depends upon the size of the individual particles. It is shown that if the dust is fine enough for τ to be small compared with a characteristic time scale associated with the flow, then the addition of dust destabilizes a gas flow; whereas if the dust is coarse so that τ is relatively large, then the dust has a stabilizing action.For plane parallel flow, it is shown that the stability characteristics for a dusty gas are still determined by solutions of the Orr-Sommerfeld equation, but with the basic velocity profile replaced by a modified profile which is in general complex. A simple, although unrealistic, example is used to illustrate some features of the action of dust. It is intended to describe the solution of the modified Orr-Sommerfeld equation for plane Poiseuille flow in a later paper.

668 citations

Journal ArticleDOI
Abstract: Gas–liquid two-phase flow patterns are visualized with a microscope for air–water flow in circular tubes of 20, 25 and 100 μm i.d. and for steam–water flow in a 50 μm i.d. circular tube. The superficial velocities cover a broad range of J L =0.003–17.52 m/s and J G =0.0012–295.3 m/s for air–water flows. Several distinctive flow patterns, namely, dispersed bubbly flow, gas slug flow, liquid ring flow, liquid lump flow, annular flow, frothy or wispy annular flow, rivulet flow, liquid droplets flow and a special type of flow pattern are identified both in air–water and steam–water systems, and their special features are described. It has been confirmed that two-phase flow patterns are sensitive to the surface conditions of the inner wall of the test tube. It has been evidenced that a stable annular flow and gas slug formation with partially stable thin liquid film formed between the tube wall and gas slugs appeared at high velocities under carefully treated clean surface conditions. At lower velocities, dry and wet areas exist between gas slug and the tube wall. The cross-sectional average void fraction was also calculated from photographs, showing a good agreement with the Armand correlation for air–water flow in lager tubes.

479 citations

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No. of papers in the topic in previous years

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Topic's top 5 most impactful authors

Peter Glarborg

12 papers, 660 citations

Ephraim M Sparrow

7 papers, 429 citations

Yogesh Jaluria

4 papers, 99 citations

Dan Taroata

3 papers, 31 citations

Dimitrios V. Papavassiliou

3 papers, 12 citations