Complete theory of the elastic wall jet: A new flow geometry with revisited two-phase nanofluids

2021 ◽  
Vol 86 ◽  
pp. 25-36
Author(s):  
Amin Jafarimoghaddam ◽  
Mustafa Turkyilmazoglu ◽  
A.V. Roşca ◽  
I. Pop
Keyword(s):  
Complete Theory ◽  
Wall Jet ◽  
Two Phase ◽  
Flow Geometry ◽  
Elastic Wall

Impingement of an unsteady two-phase jet on unheated and heated flat plates

1993 ◽  
Vol 252 ◽  
pp. 499-523 ◽  
Author(s):  
İ. Bedii Özdemir ◽  
J. H. Whitelaw
Keyword(s):  
Wall Temperature ◽  
High Speed ◽  
Continuous Phase ◽  
Size Class ◽  
Wall Jet ◽  
Flat Plates ◽  
Two Phase ◽  
Secondary Atomization ◽  
Wall Jet Flow ◽  
The Impact

This paper is concerned with an experimental investigation of the oblique impingement of an unsteady, axisymmetric two-phase jet on heated surfaces. Size and velocity were measured simultaneously with a phase-Doppler velocimeter, and the spatial distributions over the wall jet were found to be correlated with the interfacial activities as inferred from vertical velocity measurements in the vicinity of the wall. These results are discussed together with size measurements by a laser-diffraction technique to quantify the effect of the approach conditions of the inflowing jet droplet field and wall temperature in relation to mechanisms of secondary atomization.Two mechanisms of secondary atomization were identified; the first did not involve direct wall contact and was due to the strain acting on the droplets by the continuous phase within the impingement region and was enhanced by thermal effects from the wall to cause breakup. The approaching velocity of the inflowing droplets to the plate was important to this process so that higher velocities increased the rate of strain within the impingement region and, consequently, the wall temperature promoting the secondary atomization shifted towards lower values. The second mechanism required direct wall contact and involved atomization of the film deposited on the wall by the impingement of the inflowing two-phase jet. With the penetration of high-speed inflowing droplets into the film, liquid mass was raised into the two-phase medium due to splashes from the film so that a new size class with larger droplets was generated. The resulting large droplets tended to stay close to the wall within the impingement region with small vertical velocitiesIn between the injections, the suspended droplet field above the film oscillated normal to the plate as a cloud so that the impact of large droplets on the film resulted in coalescence with the film and the ejection of smaller numbers of small droplets. The unsteady wall jet flow, caused by the arrival of the spray at the plate, swept the vertically oscillating droplet cloud radially outwards so that the resulting radial transport caused the dynamics of the unsteady film to be correlated with the size characteristics of the unsteady wall jet. Based on this phenomenological description, a radial droplet transport equation is derived.The correlation suggests that the secondary atomization with direct wall contact is the dominant process for the generation of a new size class within the wall flow and initiates the mutual interaction between the unsteady film and wall jet droplet field.

Two-Phase Laminar Wall Jet Flow With Electrification of Particles

2016 ◽  
Vol 42 (9) ◽  
pp. 478-482 ◽  
Author(s):  
Pradeep Kumar Tripathy ◽  
Tumbanath Samantara ◽  
Saroj Kumar Mishra
Keyword(s):  
Jet Flow ◽  
Wall Jet ◽  
Two Phase ◽  
Wall Jet Flow

Two-phase pulsed flow of a non Newtonian fluid in pipe with elastic wall

2015 ◽  
Vol 9 ◽  
pp. 1189-1200
Author(s):  
M. Tricha ◽  
K. Gueraoui ◽  
A. Elbouzidi ◽  
B. Bahrar ◽  
A. Mzerd ◽  
...  
Keyword(s):  
Newtonian Fluid ◽  
Two Phase ◽  
Pulsed Flow ◽  
Elastic Wall

Visualization of Confined Jet Impingement With Boiling Using Time-Resolved Stereo-PIV

2015 ◽  
Author(s):  
Matthew J. Rau ◽  
Tianqi Guo ◽  
Pavlos P. Vlachos ◽  
Suresh V. Garimella
Keyword(s):  
Flow Field ◽  
Heat Source ◽  
Liquid Flow ◽  
Heated Surface ◽  
Jet Impingement ◽  
Vapor Flow ◽  
Wall Jet ◽  
Phase Flow ◽  
Two Phase ◽  
Time Resolved

Two-phase liquid-vapor flow field measurements of confined jet impingement with boiling are performed using time-resolved stereo particle image velocimetry (stereo-PIV). A single circular jet of water, impinges normally from a 3.75 mm-diameter orifice onto a submerged circular heat source at an orifice-to-target spacing of 4 jet diameters. The impinging jet outflow including the vapor generated at the heat source are confined between the jet orifice plate and the bottom test section wall. Fluorescent seeding particles (10 μm in diameter) and time-resolved PIV measurements (taken at a sampling rate of 750 Hz) allow for imaging of the instantaneous interactions between the liquid and vapor structures. Liquid-phase velocity vectors within the two-phase flow field (with high vapor fractions) are presented as a function of heat flux at jet Reynolds numbers of 5,000 and 15,000 and contrasted with single-phase flow. The time-resolved measurements are used to highlight the influence of the vapor phase on the liquid flow field. It is found that bubble formation effectively blocks the developing wall-jet flow on the heated surface. The resulting liquid flow field in the confinement gap is dominated by vapor motion rather than by the entrainment from the developing wall jet.

Three-Dimensional Laminar Wall Jet Flows

2009 ◽  
Author(s):  
Kofi K. Adane ◽  
Mark F. Tachie
Keyword(s):  
Numerical Study ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Secondary Flows ◽  
Navier Stokes ◽  
Jet Flows ◽  
Wall Jet ◽  
Navier Stokes Equation ◽  
Flow Geometry

The present article reports on both experimental and numerical study of three-dimensional laminar wall jet flows. The wall jet was created using a circular pipe of diameter 7 mm and flows into an open channel. The Reynolds numbers based on the pipe diameter and jet exit velocity were varied from 310 to 1300. A particle image velocimetry (PIV) was used to conduct detailed velocity measurements at various streamwise-transverse and streamwise-spanwise planes. A complete nonlinear incompressible Navier-Stokes equation was also solved using a co-located finite volume based in-house computational fluid dynamic (CFD) code. This code was used to compute the experimental flow geometry. From the PIV measurements and CFD results, velocities profiles and jet-half-widths were extracted at selected locations. It was observed that the numerical results are in reasonable agreement with the experimental data. The distributions of the velocities, jet-half-widths and visualisation of the secondary flows were used to provide insight into the characteristics of three-dimensional wall jet flows.

Effect of flow geometry on the rheology of dispersed two-phase blends of polystyrene and poly(methyl methacrylate)

Polymer ◽  
1995 ◽  
Vol 36 (12) ◽  
pp. 2451-2462 ◽  
Author(s):  
James H. Han ◽  
Chin Choi-Feng ◽  
De-Jie Li ◽  
Chang Dae Han
Keyword(s):  
Methyl Methacrylate ◽  
Two Phase ◽  
Poly Methyl Methacrylate ◽  
Flow Geometry

TWO-PHASE MIXTURE LEVEL SWELL DURING POOL SCRUBBING IN TERMS OF FLOW GEOMETRY

2019 ◽  
Vol 2019.27 (0) ◽  
pp. 2003
Author(s):  
Takahiro Arai ◽  
Masahiro Furuya ◽  
Hiroki Takiguchi ◽  
Kenetsu Shirakawa
Keyword(s):  
Two Phase ◽  
Flow Geometry ◽  
Phase Mixture

Effect of Shock Loading on the Microstructure of Uniloy 326

1974 ◽  
Vol 32 ◽  
pp. 504-505
Author(s):  
K. P. Staudhammer ◽  
L. E. Murr
Keyword(s):  
Grain Size ◽  
Shock Loading ◽  
Current Investigation ◽  
Two Phase ◽  
05 C ◽  
Shock Deformation ◽  
Heat Treated

The effect of shock loading on a variety of steels has been reviewed recently by Leslie. It is generally observed that significant changes in microstructure and microhardness are produced by explosive shock deformation. While the effect of shock loading on austenitic, ferritic, martensitic, and pearlitic structures has been investigated, there have been no systematic studies of the shock-loading of microduplex structures.In the current investigation, the shock-loading response of millrolled and heat-treated Uniloy 326 (thickness 60 mil) having a residual grain size of 1 to 2μ before shock loading was studied. Uniloy 326 is a two phase (microduplex) alloy consisting of 30% austenite (γ) in a ferrite (α) matrix; with the composition.3% Ti, 1% Mn, .6% Si,.05% C, 6% Ni, 26% Cr, balance Fe.

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