Poiseuille Flow With Variable Fluid Properties

1967 ◽  
Vol 89 (3) ◽  
pp. 666-674 ◽  
Author(s):  
C. F. Kettleborough
Keyword(s):  
Energy Equation ◽  
Nonlinear Effects ◽  
Momentum Equation ◽  
Parallel Channel ◽  
Dissipation Term ◽  
Variable Fluid Properties ◽  
Fluid Properties ◽  
Temperature And Pressure ◽  
Energy And Momentum ◽  
Energy Equations

Flow of a fluid through a parallel channel is one of the simplest types of flow. However, the equations of flow and energy are far from simple and can only be solved in a closed form in the simplest cases when nonlinear effects such as the inertia and convective terms can be neglected (i.e., for zero Reynolds number) and when the energy and momentum equations are uncoupled. A numerical iterative method is described in which the coupled momentum and energy equations are solved when the viscosity, thermal conductivity and specific heat are functions of temperature, and the density a function of temperature and pressure; inertia terms are retained in the momentum equation and the convective terms, compression work term and the predominant dissipation term retained in the energy equation. Results are obtained for a variety of boundary temperatures up to about 2400 deg F and the effect of variable fluid properties and various terms in the energy and momentum equation are shown.

scholarly journals Nonlinear wave energy modelling in the surf zone

1996 ◽  
Vol 3 (2) ◽  
pp. 127-134 ◽  
Author(s):  
Th. V. Karambas
Keyword(s):  
Wave Energy ◽  
Surf Zone ◽  
Energy Balance Equation ◽  
Propagation Model ◽  
Breaking Wave ◽  
Dissipation Term ◽  
Energy Modelling ◽  
Turbulence Effects ◽  
Energy And Momentum ◽  
Energy Equations

Abstract. Breaking wave energy in the surf zone is modelled through the incorporation of the time dependent energy balance equation in a non linear dispersive wave propagation model. The energy equations solved simultaneously with the momentum and continuity equation. Turbulence effects and the non uniform horizontal velocity distribution due to breaking is introduced in both the energy and momentum equations. The dissipation term is a function of the velocity defect derived from a turbulent analysis. The resulting system predicts both wave characteristics (surface elevation and velocity) and the energy distribution inside surf zone. The model is validated against experimental data and analytical expressions.

Parallel Surface Squeeze Films: The Effect of the Variation of Viscosity With Temperature and Pressure

1967 ◽  
Vol 89 (3) ◽  
pp. 375-380 ◽  
Author(s):  
P. Gould
Keyword(s):  
High Pressure ◽  
Constant Velocity ◽  
Dimensionless Parameter ◽  
Load Capacity ◽  
Mineral Oil ◽  
Fluid Temperature ◽  
Parallel Surface ◽  
Fluid Properties ◽  
Temperature And Pressure ◽  
Energy Equations

A study is presented of high-pressure squeeze films between flat disks which approach each other at a constant velocity. The dependence of the viscosity of the oil on the fluid temperature and pressure is included in the momentum and energy equations. A single dimensionless parameter which involves only fluid properties determines whether the load capacity will be greater or less than that predicted by an isoviscous analysis. Excellent agreement is found between the results of a numerical analysis and the results of experiments in which mineral oil is confined between steel boundaries.

Influence of Non-Equilibrium Fluid Properties During Fogging on Intake Duct and Compressor Characteristics

2017 ◽  
Author(s):  
Christoph Günther ◽  
Franz Joos
Keyword(s):  
Relative Humidity ◽  
Gas Turbine ◽  
Thermophysical Properties ◽  
Ambient Air ◽  
Compressor Stage ◽  
Compression Process ◽  
Fluid Properties ◽  
Temperature And Pressure ◽  
Gas Turbine Compressor ◽  
Non Equilibrium

This study reports on numerically calculated thermophysical properties of air passing through a gas turbine compressor after passage through an intake duct affected by wet compression. Case of reference is unaffected ambient air (referenced to as dry scenario) passing through intake duct and compressor. Furthermore, ambient air cooled down by (overspray) fogging (referenced to as wet scenarios) was considered. Acceleration at the end of intake duct causing reduction of static temperature and pressure results in supersaturated fluid properties at inlet to gas turbine compressor. These supersaturated fluid properties are non-equilibrium with saturation level above relative humidity of φ = 1. Entrance of supersaturated fluid into gas turbine compressor can result in condensation within first compressor stage. At the same time delayed impact of evaporative cooling influences compression process.

scholarly journals Turbulence kinetic energy exchanges in flows with highly variable fluid properties

2017 ◽  
Vol 834 ◽  
pp. 5-54 ◽  
Author(s):  
Dorian Dupuy ◽  
Adrien Toutant ◽  
Françoise Bataille
Keyword(s):  
Reynolds Number ◽  
Temperature Gradient ◽  
Velocity Fluctuation ◽  
Spectral Studies ◽  
Spectral Energy ◽  
Correlation Tensor ◽  
Variable Fluid Properties ◽  
Fluid Properties ◽  
Energy Exchanges ◽  
The Mean

This paper investigates the energy exchanges associated with the half-trace of the velocity fluctuation correlation tensor in a strongly anisothermal low Mach fully developed turbulent channel flow. The study is based on direct numerical simulations of the channel within the low Mach number hypothesis and without gravity. The overall flow behaviour is governed by the variable fluid properties. The temperature of the two channel walls are imposed at 293 K and 586 K to generate the temperature gradient. The mean friction Reynolds number of the simulation is 180. The analysis is carried out in the spatial and spectral domains. The spatial and spectral studies use the same decomposition of the terms of the evolution equation of the half-trace of the velocity fluctuation correlation tensor. The importance of each term of the decomposition in the energy exchanges is assessed. This lets us identify the terms associated with variations or fluctuations of the fluid properties that are not negligible. Then, the behaviour of the terms is investigated. The spectral energy exchanges are first discussed in the incompressible case since the analysis is not present in the literature with the decomposition used in this study. The modification of the energy exchanges by the temperature gradient is then investigated in the spatial and spectral domains. The temperature gradient generates an asymmetry between the two sides of the channel. The asymmetry can in a large part be explained by the combined effect of the mean local variations of the fluid properties, combined with a Reynolds number effect.

scholarly journals The Importance of Nanoparticles Addition in a Base Fluid Flow through a Porous Medium

2013 ◽  
Vol 8-9 ◽  
pp. 225-234
Author(s):  
Dalia Sabina Cimpean
Keyword(s):  
Porous Medium ◽  
Fluid Flow ◽  
Boundary Conditions ◽  
Mixed Convection ◽  
Mathematical Models ◽  
Base Fluid ◽  
Porous Matrix ◽  
Fluid Properties ◽  
Flow Through ◽  
Energy Equations

The present study is focused on the mixed convection fluid flow through a porous medium, when a different amount of nanoparticles is added in the base fluid. The nanofluid saturates the porous matrix and different situations of the flow between two walls are presented and discussed. Alternatively mathematical models are presented and discussed. A solution of a system which contains the momentum, Darcy and energy equations, together with the boundary conditions involved, is given. The behavior of different nanofluids, such thatAu-water, Ag-waterandFe-wateris graphically illustrated and compared with the previous results.The research target is to observe the substantial increase of the thermophysical fluid properties, when the porous medium issaturated by a nanofluid instead of a classical Newtonian fluid.

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