scholarly journals EVALUATION OF THE FEATURES OF THE STRUCTURE OF WATER AND AQUEOUS SOLUTIONS NEAR A SOLID SURFACE

Globus ◽  
2021 ◽  
Vol 7 (6(63)) ◽  
pp. 10-16
Author(s):  
Galina Nikolaevna Sidorenko ◽  
Boris Innokentievich Laptev ◽  
Nikolai Petrovich Gorlenko
Keyword(s):  
Boundary Layer ◽  
Aqueous Solutions ◽  
Solid Surface ◽  
Structural Organization ◽  
Wall Layer ◽  
Electrical Capacitance ◽  
Structure Of Water ◽  
Wall Boundary Layer ◽  
Electric Capacity ◽  
Surface Changes

The paper evaluates changes in the structure of water and aqueous solutions of sodium chloride in the wall layer on the basis of dielectrometry and correlation analysis. It is shown that when the distance to the solid surface decreases, there is a multi-fold nonlinear decrease in the electrical capacitance and a nonlinear change in the Sr parameter, which characterizes the magnitude of the change in the electrical capacitance of the conduction fluid when the distance to the solid surface changes. The parameters used in the work (electric capacity of liquids and Sr ) can be used to evaluate the changes in the structural organization of aqueous solutions in the wall (boundary) layer and to interpret the processes occurring in the liquid layer at the interface of the solid – aqueous solution phases.

Evaluation of Changing the Structure of Water and Aqueous Solutions by External Influences

2015 ◽  
Vol 22 (2) ◽  
pp. 88-96
Author(s):  
Горленко ◽  
N. Gorlenko ◽  
Антошкин ◽  
L. Antoshkin ◽  
Саркисов ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Aqueous Solutions ◽  
Methodological Approach ◽  
Temperature Influence ◽  
Oscillatory Circuit ◽  
Structure Of Water ◽  
Electric Capacity ◽  
Free Molecules ◽  
Field Influence

With use of the new methodological approach the changes of structure of water and aqueous solutions are investigated at the various influences including change of temperature, influence of magnetic field, influence of a material of a surface in boundary layer and other factors. It is shown, that rising (depression) of electric capacity and (or) Q of an oscillatory circuit at the used influences reflect an ascending (a decrease) of mobility of dipoles of water in a variable electric floor (at usual and (or) resonant regimens of its influence) and, obviously, testify to decrease (augmentation) of structure of water and aqueous solutions. The structure of water and aqueous solutions, evidentiary, depends on the amount of free molecules of water and associate molecules of water, for example, in cluster, hydrated formations and interaction between them, and also from change of concentration of the dissolved gases.

Turbulent boundary-layer interaction with a shock wave at a compression corner

1984 ◽  
Vol 143 ◽  
pp. 23-46 ◽  
Author(s):  
S. Agrawal ◽  
A. F. Messiter
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Turbulent Boundary Layer ◽  
Momentum Equation ◽  
Wall Layer ◽  
Oblique Shock Wave ◽  
Mean Velocity ◽  
Law Of The Wall ◽  
Compression Corner ◽  
Boundary Layer Interaction

The local interaction of an oblique shock wave with an unseparated turbulent boundary layer at a shallow two-dimensional compression corner is described by asymptotic expansions for small values of the non-dimensional friction velocity and the flow turning angle. It is assumed that the velocity-defect law and the law of the wall, adapted for compressible flow, provide an asymptotic representation of the mean velocity profile in the undisturbed boundary layer. Analytical solutions for the local mean-velocity and pressure distributions are derived in supersonic, hypersonic and transonic small-disturbance limits, with additional intermediate limits required at distances from the corner that are small in comparison with the boundary-layer thickness. The solutions describe small perturbations in an inviscid rotational flow, and show good agreement with available experimental data in most cases where effects of separation can be neglected. Calculation of the wall shear stress requires solution of the boundary-layer momentum equation in a sublayer which plays the role of a new thinner boundary layer but which is still much thicker than the wall layer. An analytical solution is derived with a mixing-length approximation, and is in qualitative agreement with one set of measured values.

Experiments on Flame Flashback in a Quasi-2D Turbulent Wall Boundary Layer for Premixed Methane-Hydrogen-Air Mixtures

2010 ◽  
Author(s):  
Christian Eichler ◽  
Thomas Sattelmayer
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Turbulent Flows ◽  
Turbulent Transport ◽  
Wall Friction ◽  
Evaluation Procedure ◽  
Wall Boundary Layer ◽  
Wall Boundary ◽  
Flame Flashback ◽  
Turbulent Wall

Premixed combustion of hydrogen-rich mixtures involves the risk of flame flashback through wall boundary layers. For laminar flow conditions, the flashback mechanism is well understood and is usually correlated by a critical velocity gradient at the wall. Turbulent transport inside the boundary layer considerably increases the flashback propensity. Only tube burner setups have been investigated in the past and thus turbulent flashback limits were only derived for a fully-developed Blasius wall friction profile. For turbulent flows, details of the flame propagation in proximity to the wall remain unclear. This paper presents results from a new experimental combustion rig, apt for detailed optical investigations of flame flashbacks in a turbulent wall boundary layer developing on a flat plate and being subject to an adjustable pressure gradient. Turbulent flashback limits are derived from the observed flame position inside the measurement section. The fuels investigated cover mixtures of methane, hydrogen and air at various mixing ratios. The associated wall friction distributions are determined by RANS computations of the flow inside the measurement section with fully resolved boundary layers. Consequently, the interaction between flame back pressure and incoming flow is not taken into account explicitly, in accordance with the evaluation procedure used for tube burner experiments. The results are compared to literature values and the critical gradient concept is reviewed in light of the new data.

Structural Organization of Interpolymer Complexes Formed by Poly(N-vinylamides) and Poly(methacrylic acid) Chains Regularly Grafted to Polyimide in Aqueous Solutions

2018 ◽  
Vol 60 (S1) ◽  
pp. 172-178 ◽  
Author(s):  
T. N. Nekrasova ◽  
V. D. Pautov ◽  
T. D. Anan’eva ◽  
T. K. Meleshko ◽  
I. V. Ivanov ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Methacrylic Acid ◽  
Structural Organization ◽  
Interpolymer Complexes

Annulus Wall Boundary-Layer Measurements in a Four-Stage Compressor

1986 ◽  
Vol 108 (1) ◽  
pp. 2-6 ◽  
Author(s):  
N. A. Cumpsty
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Layer Thickness ◽  
Boundary Layers ◽  
Boundary Layer Thickness ◽  
Tip Clearance ◽  
The Other ◽  
Wall Boundary Layer ◽  
Multistage Compressors ◽  
Full Design

There are few available measurements of the boundary layers in multistage compressors when the repeating-stage condition is reached. These tests were performed in a small four-stage compressor; the flow was essentially incompressible and the Reynolds number based on blade chord was about 5 • 104. Two series of tests were performed; in one series the full design number of blades were installed, in the other series half the blades were removed to reduce the solidity and double the staggered spacing. Initially it was wished to examine the hypothesis proposed by Smith [1] that staggered spacing is a particularly important scaling parameter for boundary layer thickness; the results of these tests and those of Hunter and Cumpsty [2] tend to suggest that it is tip clearance which is most potent in determining boundary-layer integral thicknesses. The integral thicknesses agree quite well with those published by Smith.

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