scholarly journals Temperature-Dependent Viscosity Model for Silicone Oil and Its Application in Viscous Dampers

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 331
Author(s):  
Márk Venczel ◽  
Gabriella Bognár ◽  
Árpád Veress
Keyword(s):  
Shear Rate ◽  
Torsional Vibration ◽  
Transient Flow ◽  
Silicone Oil ◽  
Viscosity Model ◽  
Working Fluid ◽  
Oil Viscosity ◽  
Temperature Dependent ◽  
Wide Range ◽  
Dependent Viscosity

Silicone fluids belong to the group of pseudoplastic non-Newtonian fluids with complex rheological characteristics. They are considered in basic and applied researches and in a wide range of industrial applications due to their favorable physical and thermal properties. One of their specific field of applications in the automotive industry is the working fluid of viscous torsional vibration dampers. For numerical studies in the design and development phase of this damping product, it is essential to have thorough rheological knowledge and mathematical description about the silicone oil viscosity. In the present work, adopted rheological measurement results conducted on polydimethylsiloxane manufactured by Wacker Chemie with initial viscosity of 1000 Pas (AK 1 000 000 STAB silicone oil) are processed. As a result of the parameter identification by nonlinear regression, the temperature-dependent parameter curves of the Carreau–Yasuda non-Newtonian viscosity model are generated. By implementing these parameter sets into a Computational Fluid Dynamics (CFD) software, a temperature- and shear-rate-dependent viscosity model of silicone fluid was tested, using transient flow and thermal simulations on elementary tube geometries in the size range of a real viscous torsional vibration damper’s flow channels and filling chambers. The numerical results of the finite volume method provide information about the developed flow processes, with especial care for the resulted flow pattern, shear rate, viscosity and timing.

scholarly journals Effect of Porous Medium and Copper Heat Sink on Cooling of Heat-Generating Element

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2538 ◽  
Author(s):  
Marina Astanina ◽  
Mikhail Sheremet ◽  
U. S. Mahabaleshwar ◽  
Jitender Singh
Keyword(s):  
Energy Transport ◽  
Cooling System ◽  
Variable Viscosity ◽  
Optimal Number ◽  
Working Fluid ◽  
Heat Conducting ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Negative Effect ◽  
Dependent Viscosity

Cooling of heat-generating elements is a challenging problem in engineering. In this article, the transient free convection of a temperature-dependent viscosity liquid inside the porous cavity with copper radiator and the heat-generating element is studied using mathematical modeling techniques. The vertical and top walls of the chamber are kept at low constant temperature, while the bottom wall is kept adiabatic. The working fluid is a heat-conducting liquid with temperature-dependent viscosity. A mathematical model is developed based on dimensionless stream function, vorticity, and temperature variables. The governing properties are the variable viscosity, geometric parameters of the radiator, and size of thermally insulated strip on vertical surfaces of the cavity. The effect of these parameters on the energy transport and circulation patterns are analyzed numerically. Based on the numerical results obtained, recommendations are given on the optimal values of the governing parameters for the effective operation of the cooling system. It is shown that the optimal number of radiator fins for the cooling system configuration under consideration is 3. In addition, the thermal insulation of the vertical walls and the increased thickness of the radiator fins have a negative effect on the operation of the cooling system.

A numerical study of solidification and viscous dissipation effects on polymer melt flow in plane channels

2013 ◽  
Vol 33 (2) ◽  
pp. 95-110
Author(s):  
Mustafa Tutar ◽  
Ali Karakus
Keyword(s):  
Shear Rate ◽  
Phase Change ◽  
Viscous Dissipation ◽  
Polymer Melt ◽  
Viscous Heating ◽  
Transient Phase ◽  
Melt Flow ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Dependent Viscosity

Abstract The combined effects of solidification and viscous dissipation on the hydrodynamic and thermal behavior of polymer melt flow during the injection process in a straight plane channel of constant cross section are numerically studied by considering the shear-rate and temperature-dependent viscosity and transient-phase change behavior. A numerical finite volume method, in conjunction with a modified form of the Cross constitutive equation to account for shear rate, temperature-dependent viscosity changes and a slightly modified form of the method proposed by Voller and Prakash to account for solidification of the liquid phase, is used and a validation with an analytical solution is presented for viscous heating effects. The hydrodynamic and solidified layers growth under the influence of a transient phase-change process and viscous dissipation, are analyzed for a commercial polymer melt flow, polypropylene (PP) for different parametric conditions namely, inflow velocity, polymer injection (inflow) temperature, the channel wall temperature, and the channel height. The results demonstrate that the proposed numerical formulations, including conjugate effects of viscous heating and transient-solidification on the present thermal transport process, can provide an accurate and realistic representation of polymer melt flow behavior during the injection molding process in plane channels with less simplifying assumptions.

scholarly journals Effect of Soret and Temperature Dependent Viscosity on Thermohaline Convection in a Ferrofluid Saturating a Porous Medium

2014 ◽  
Vol 19 (2) ◽  
pp. 321-336
Author(s):  
R. Sekar ◽  
K. Raju
Keyword(s):  
Porous Medium ◽  
Fluid Layer ◽  
Effect Of Temperature ◽  
Stationary Mode ◽  
Free Boundaries ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Onset Of Convection ◽  
Wide Range ◽  
Dependent Viscosity

Abstract Soret driven ferrothermoconvective instability in multi-component fluids has a wide range of applications in heat and mass transfer. This paper deals with the theoretical investigation of the effect of temperature dependent viscosity on a Soret driven ferrothermohaline convection heated from below and salted from above subjected to a transverse uniform magnetic field in the presence of a porous medium. The Brinkman model is used in the study. It is found that the stationary mode of instability is preferred. For a horizontal fluid layer contained between two free boundaries an exact solution is examined using the normal mode technique for a linear stability analysis. The effect of salinity has been included in magnetization and density of the fluid. The critical thermal magnetic Rayleigh number for the onset of instability is obtained numerically for sufficiently large values of the buoyancy magnetization parameter M1 using the method of numerical Galerkin technique. It is found that magnetization and permeability of the porous medium destabilize the system. The effect of temperature dependent viscosity stabilizes the system on the onset of convection.

Entrance, Viscous Dissipation and Temperature Dependent Viscosity Effects on the Laminar Forced Convection in Straight Microchannels With Uniform Wall Heat Flux

2008 ◽  
Author(s):  
C. Nonino ◽  
S. Savino ◽  
S. Del Giudice
Keyword(s):  
Heat Flux ◽  
Forced Convection ◽  
Viscous Dissipation ◽  
Laminar Flows ◽  
Uniform Heat Flux ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Wide Range ◽  
Dependent Viscosity ◽  
Laminar Forced Convection

A parametric investigation is carried out on the effects of viscous dissipation and temperature dependent viscosity in simultaneously developing laminar flows of liquids in straight microchannels of constant cross-sections. Reference is made to fluid heating conditions with a uniform heat flux imposed on the walls of the microchannels. Three different cross-sectional geometries are considered, chosen among those usually adopted for microchannels (rectangular, trapezoidal and hexagonal). Viscosity is assumed to vary with temperature according to an exponential relation, while the other fluid properties are held constant. A finite element procedure is employed for the solution of the parabolized momentum and energy equations. Due to the high value of the ratio between the total length and the hydraulic diameter in microchannels, such an approach is very advantageous with respect to the one based on the steady-state solution of the elliptic form of the governing equations in a three-dimensional domain corresponding to the whole duct. Computed axial distributions of the local Nusselt number and of the apparent Fanning friction factor are presented. Numerical results confirm that, in the laminar forced convection in the entrance region of straight microchannels, the effects of viscous dissipation and temperature dependent viscosity cannot be neglected in a wide range of operative conditions.

Studies on Methacryloyl Guar Gum: Surface Morphology, Crystallinity, Biodegradability and Viscosity Behavior of Semi-Dilute Solutions

2011 ◽  
Vol 279 ◽  
pp. 327-332
Author(s):  
Wen Fa Xiao ◽  
Li Tao Dong
Keyword(s):  
Shear Rate ◽  
Surface Morphology ◽  
Guar Gum ◽  
Viscosity Model ◽  
Dilute Solutions ◽  
Shear Dependent Viscosity ◽  
Viscosity Behavior ◽  
The Cross ◽  
Dependent Viscosity

Methacryloyl guar gum was investigated with respect to crystallinity, surface morphology, biodegradability and viscosity of semi-dilute solutions. It was studied that the shear-dependent viscosity behaviour could be well described by the Cross viscosity model, under various methacryloyl guar gum concentrations, salts addition and temperature. The zero-shear-rate viscosity was observed to change with different methacryloyl guar gum concentration and decease with the increase of temperature.

Rheological properties of rainbow trout blood

1987 ◽  
Vol 65 (4) ◽  
pp. 879-883 ◽  
Author(s):  
Garth L. Fletcher ◽  
R. Tyson Haedrich
Keyword(s):  
Rainbow Trout ◽  
Shear Rate ◽  
Salvelinus Alpinus ◽  
Salmo Gairdneri ◽  
Pseudopleuronectes Americanus ◽  
Temperature Dependent ◽  
Shear Dependent Viscosity ◽  
Myoxocephalus Scorpius ◽  
Lower Temperature ◽  
Dependent Viscosity

The effects of shear rate and red cell concentration on the viscosity of rainbow trout (Salmo gairdneri) blood were evaluated at 0 and 15 °C using a cone-plate viscometer. The viscosity of blood was shear dependent at both temperatures, with the highest values occurring at the lower temperature and shear rate. The viscosity of plasma was not shear dependent. Viscosity of blood increased in a linear fashion between hematocrits of 0 and 40%. Viscosity of the rainbow trout blood was similar to that of arctic char (Salvelinus alpinus), but considerably lower and less shear and temperature dependent than the bloods of winter flounder (Pseudopleuronectes americanus) and shorthorn sculpin (Myoxocephalus scorpius). It is hypothesized that low shear and temperature dependent blood viscosity may be a characteristic of active fish.

Sign in / Sign up

Export Citation Format

Share Document