The influence of temperature dependence of viscosity on stability liquid flows in a plane channel

2014 ◽  
Vol 10 ◽  
pp. 90-94 ◽  
Author(s):  
A.D. Nizamova
Keyword(s):  
Temperature Dependence ◽  
Liquid Flow ◽  
Plane Channel ◽  
Isothermal Flow ◽  
Uniform Temperature ◽  
Influence Of Temperature ◽  
Uniform Temperature Field ◽  
The Stability ◽  
Liquid Flows ◽  
Sommerfeld Equation

The influence problem of temperature dependence of viscosity on stability of liquid flow in a plane channel under non-uniform temperature field was considered. The system of two ordinary differential equations for the perturbation amplitudes of velocity and temperature was received. In the case of isothermal flow, derived system can be reduced to the Orr-Sommerfeld equation. The spectra of eigenvalues for Poiseuille flow with different temperature dependence of viscosity were numerical studied. It is shown that temperature dependence of viscosity has an influence on the stability of the liquid flow.

scholarly journals Mathematical Model of a Heating Furnace Implemented with Volumetric Fuel Combustion

Processes ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 469
Author(s):  
Miroslav Rimar ◽  
Andrii Kulikov ◽  
Marcel Fedak ◽  
Oleksandr Yeromin ◽  
Kostyantyn Sukhyy ◽  
...  
Keyword(s):  
Large Scale ◽  
Main Type ◽  
Heating Furnace ◽  
Uniform Temperature ◽  
Influence Of Temperature ◽  
Working Chamber ◽  
Furnace Gases ◽  
Uniform Temperature Field ◽  
Metal Products ◽  
Working Parameters

Heating flame furnaces are the main type of furnaces used for heating and heat treatment of metal products in metallurgy and mechanical engineering. In the working chamber of a modern heating furnace, there should be neither high-temperature nor stagnation zones. One of the methods used to provide such combustion conditions is the application of distributed (volumetric) combustion. Owing to this method, heating quality is ensured by creating a uniform temperature field and equivalent heat exchange conditions, regardless of the placement of the charge in the working chamber of the furnace. In this work, we numerically study the volumetric combustion and influences of small- and large-scale recirculation ratios of furnace gases, the influence of temperature fluctuation on the regenerator nozzle, and the working parameters at the starting phase and reverse.

Influence of viscosity temperature dependence on the spectral characteristics of the thermoviscous liquids flow stability equation

2019 ◽  
Vol 14 (1) ◽  
pp. 52-58 ◽  
Author(s):  
A.D. Nizamova ◽  
V.N. Kireev ◽  
S.F. Urmancheev
Keyword(s):  
Reynolds Number ◽  
Spectral Characteristics ◽  
Wave Number ◽  
Critical Parameters ◽  
Fluid Viscosity ◽  
Flat Channel ◽  
Stability Equation ◽  
The Stability ◽  
Thermoviscous Fluid ◽  
Sommerfeld Equation

The flow of a viscous model fluid in a flat channel with a non-uniform temperature field is considered. The problem of the stability of a thermoviscous fluid is solved on the basis of the derived generalized Orr-Sommerfeld equation by the spectral decomposition method in Chebyshev polynomials. The effect of taking into account the linear and exponential dependences of the fluid viscosity on temperature on the spectral characteristics of the hydrodynamic stability equation for an incompressible fluid in a flat channel with given different wall temperatures is investigated. Analytically obtained profiles of the flow rate of a thermovisible fluid. The spectral pictures of the eigenvalues of the generalized Orr-Sommerfeld equation are constructed. It is shown that the structure of the spectra largely depends on the properties of the liquid, which are determined by the viscosity functional dependence index. It has been established that for small values of the thermoviscosity parameter the spectrum compares the spectrum for isothermal fluid flow, however, as it increases, the number of eigenvalues and their density increase, that is, there are more points at which the problem has a nontrivial solution. The stability of the flow of a thermoviscous fluid depends on the presence of an eigenvalue with a positive imaginary part among the entire set of eigenvalues found with fixed Reynolds number and wavenumber parameters. It is shown that with a fixed Reynolds number and a wave number with an increase in the thermoviscosity parameter, the flow becomes unstable. The spectral characteristics determine the structure of the eigenfunctions and the critical parameters of the flow of a thermally viscous fluid. The eigenfunctions constructed in the subsequent works show the behavior of transverse-velocity perturbations, their possible growth or decay over time.

scholarly journals Velocity bias in intrusive gas-liquid flow measurements

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
B. Hohermuth ◽  
M. Kramer ◽  
S. Felder ◽  
D. Valero
Keyword(s):  
Liquid Flow ◽  
Breaking Waves ◽  
Correction Method ◽  
Force Balance ◽  
Bubble Velocity ◽  
Natural Environments ◽  
Flow Measurements ◽  
Gas Liquid Flow ◽  
Liquid Flows ◽  
Velocity Bias

AbstractGas–liquid flows occur in many natural environments such as breaking waves, river rapids and human-made systems, including nuclear reactors and water treatment or conveyance infrastructure. Such two-phase flows are commonly investigated using phase-detection intrusive probes, yielding velocities that are considered to be directly representative of bubble velocities. Using different state-of-the-art instruments and analysis algorithms, we show that bubble–probe interactions lead to an underestimation of the real bubble velocity due to surface tension. To overcome this velocity bias, a correction method is formulated based on a force balance on the bubble. The proposed methodology allows to assess the bubble–probe interaction bias for various types of gas-liquid flows and to recover the undisturbed real bubble velocity. We show that the velocity bias is strong in laboratory scale investigations and therefore may affect the extrapolation of results to full scale. The correction method increases the accuracy of bubble velocity estimations, thereby enabling a deeper understanding of fundamental gas-liquid flow processes.

Temperature dependence of the stability of tobramycin mixed with penicillins in human serum

1982 ◽  
Vol 39 (6) ◽  
pp. 1005-1008
Author(s):  
Kimberly A. O'Bey ◽  
Lucia K. Jim ◽  
Joseph P. Gee ◽  
Robert M. Johnson
Keyword(s):  
Temperature Dependence ◽  
Human Serum ◽  
The Stability

Electrical Conductivity of Chloro(phenyl)glyoxime and Its Co(II), Ni(II) and Cu(II) Complexes

2003 ◽  
Vol 68 (7) ◽  
pp. 1233-1242 ◽  
Author(s):  
Orhan Turkoglu ◽  
Mustafa Soylak ◽  
Ibrahim Belenli
Keyword(s):  
Electrical Conductivity ◽  
Temperature Dependence ◽  
Electric Conductivity ◽  
Crystal Structures ◽  
Elemental Analysis ◽  
Analysis Data ◽  
Elemental Analysis Data ◽  
The Stability ◽  
Xrd Patterns ◽  
Metal Ligand

Chloro(phenyl)glyoxime, a vicinal dioxime, and its Ni(II), Cu(II) and Co(II) complexes were prepared. XRD patterns of the complexes point to similar crystal structures. IR and elemental analysis data revealed the 1:2 metal-ligand ratio in the complexes. The Co(II) complex is a dihydrate. Temperature dependence of electrical conductivity of the solid ligand and its complexes was measured in the temperature range 25-250 °C; it ranged between 10-14-10-6 Ω-1 cm-1 and increased with rising temperature. The activation energies were between 0.61-0.80 eV. The Co(II) complex has lower electric conductivity than the Ni(II) and Cu(II) complexes. This difference in the conductivity has been attributed to differences in the stability of the complexes.

Stability of two-layer stratified flow in inclined channels: applications to air entrainment in coating systems

1996 ◽  
Vol 312 ◽  
pp. 173-200 ◽  
Author(s):  
Yuan C. Severtson ◽  
Cyrus K. Aidun
Keyword(s):  
Spectral Decomposition ◽  
Air Entrainment ◽  
Density Variation ◽  
Generalized Eigenvalue ◽  
Long Wave ◽  
Inclined Channels ◽  
The Stability ◽  
Air Liquid Interface ◽  
Sommerfeld Equation ◽  
Interfacial Mode

To understand the physics of air entrainment in thin-film liquid coating and other applications, the stability characteristics of general stratified two-layer Poiseuille-Couette flow are examined in inclined channels. Only one mode of instability, the interfacial mode, is obtained in the long-wave asymptotic limit. The generalized eigenvalue problem, formed by spectral decomposition and solution of the general two-layer Orr-Sommerfeld equation, is solved to obtain all of the critical modes. Analysis of the air/liquid interface corresponding to experiments reveals that because of the large density variation between the two layers, the interfacial mode is the only mode of instability in air entrainment. Results from the stability analysis of the flow near the contact line where air entrainment occurs are consistent with previous experimental observations.

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