Fluid Thermal Conductivity Research Articles

Flow and heat transfer in screw extruders: I. A variational analysis applied in helical co‐ordinates

AbstractA variational analysis is applied in helical co‐ordinates to the problem of a developed, steady‐state flow in a screw extruder. The functional involves only two dimensionless coordinates and is suitable for minimisation, e.g. by the finite element method. It is applicable to non‐isothermal, purely viscous flows and contains terms representing effects of inertia, convective and conductive transport of heat, pressure gradient, and viscous dissipation. The analysis takes account of the true helical geometry and involves assumptions only in taking the fluid density, specific heat and thermal conductivity of the fluid to be constant, in regarding the fluid to be homogeneous and isotropic, and in simplifying the pressure distribution.

The theory of the technique

The theory of the hot wire method of fluid thermal conductivity measurement is reviewed in detail and extended where necessary for application to an experimental system. Particular attention is given to assessing the size of approximations introduced in setting up the mathematical model of the cell which relates the observed quantities to the fluid thermal conductivity.

Thermal conductivity of fluids. n-pentane

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThermal conductivity of fluids. n-pentaneL. T. Carmichael, Joan Jacobs, and Bruce H. SageCite this: J. Chem. Eng. Data 1969, 14, 1, 31–37Publication Date (Print):January 1, 1969Publication History Published online1 May 2002Published inissue 1 January 1969https://doi.org/10.1021/je60040a032RIGHTS & PERMISSIONSArticle Views210Altmetric-Citations15LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (638 KB) Get e-Alerts Get e-Alerts

Thermal conductivity of fluids. A mixture of methane and n-butane

Thermal conductivity of fluids. A mixture of methane and n-butane

Thermal conductivity of fluids. Propane

Thermal conductivity of fluids. Propane

Thermal conductivity of fluids. n-Decane

Thermal conductivity of fluids. n-Decane

Laminar flow heat transfer

AbstractNumerical solutions of the equations of motion and energy for the heating of non‐Newtonian fluids in rectilinear, axisymmetric laminar flow in tubes of circular cross section are extended to the case of cooling at constant tube‐wall temperature. The fluid density, heat capacity, and thermal conductivity are assumed constant, but the flow properties are represented by the temperature‐dependent equation τ = m(Ṡ exp ΔH‡/RT)n. The results are presented as plots of average NNu vs. NGz, with flow and temperature‐effect indices as parameters. The mean deviation of experimental data for the cooling of aqueous CMC and carbopol dispersions from the numerical solutions is ±8%.

Thermal Conductivity of Fluids. Methane

Thermal Conductivity of Fluids. Methane

Thermal conductivity and viscosity of simple fluids

The behavior of the thermal conductivity and viscosity coefficient of simple fluids as a function of pressure, density and temperature is surveyed. Particular attention is given to the behavior of the transport coefficients in the critical region. In a previous paper [1] it was shown that the thermal conductivity coefficient exhibits a pronounced maximum in the critical region. Additional information confirming the existence of such a maximum is presented. Theoretical predictions of the transport coefficients in dense systems are often based on the theory of Enskog. A survey is presented showing to what extent the theory of Enskog describes the density dependence of the transport coefficients in monatomic fluids. Finally, the transport mechanism leading to the anomalous rise of the thermal conductivity in the critical region is indicated.

Thermal Conductivity of Fluids. n-Butane.

Thermal Conductivity of Fluids. <i>n</i>-Butane.

Thermal Conductivity of Fluids. Ammonia.

Thermal Conductivity of Fluids. Ammonia.

Thermal Conductivity of Fluids. Ethane.

Thermal Conductivity of Fluids. Ethane.

Thermal Conductivity of Fluids. Nitrous Oxide.

Thermal Conductivity of Fluids. Nitrous Oxide.

Approximate Theory of Viscosity and Thermal Conductivity in Dense Polyatomic Fluids

Formulas are derived for the collisional contributions to the pressure tensor and heat-flux vector in fluids composed of molecules which interact with impulsive forces. An approximation scheme is then employed to obtain ``zero-order'' estimates of the viscosity and thermal conductivity coefficients for various molecular models. The models considered are rough spherical and rigid convex molecular ``cores'' surrounded by potential staircases. The viscosity and thermal conductivity coefficients determined for the special case of cores surrounded by a square-well attractive potential are found to vary approximately as T1/2 eA/T at ordinary liquid temperatures. Calculations are also presented of the variations of the transport coefficients with molecular shape and eccentricity parameters.

The Thermal Conductivities of some Biological Fluids

The thermal conductivities of blood, blood plasma, blood corpuscles, cow's milk, skimmed milk, top of milk, cream, egg white, egg yolk and cod liver oil have been measured by a comparative method. Calibration of the apparatus was performed with seven liquids, chosen for the reliability of the published values of their thermal conductivities.For the biological fluids studied, a correlation has been found between thermal conductivity and water content. Results of other workers for animal tissues are fitted approximately by this correlation, which may therefore be of some assistance in estimating the thermal conductivities of body components for which no direct determinations exist.

Heat transfer characteristics of porous rocks

AbstractEquations are derived for predicting the effective thermal conductivity of beds of unconsolidated particles containing stagnant fluid. The effective thermal conductivity at these conditions, called the stagnant conductivity, is a function of the thermal conductivities of the solid and fluid phases, the void fraction, and, if radiation is important, the emissivity, mean temperature, and diameter of the solid particles. Comparison with the available experimental data indicates that the equations are satisfactory for fluids and solid particles of both high and low thermal conductivities.To extend the theory to beds of consolidated particles, it is supposed that consolidated beds are formed by partial clogging and cementing of beds of unconsolidated particles. With this assumption the theoretical equations for packed beds are extended to include such materials as sandstone and porous metals. The resulting expressions for the stagnant conductivity involve a consolidation parameter characteristic of the solid material. This quantity accounts for the heat transfer across the contact surfaces between cemented or clogged particles. The equations correctly predict the effect of void fraction and solid and fluid thermal conductivities on the heat transfer properties of sandstones and sintered metal systems.

Outlines of an Optical Method of Measuring Thermal Conductivities of Fluids.

Outlines of an Optical Method of Measuring Thermal Conductivities of Fluids.

Thermal Conductivity of Fluids. Nitric Oxide.

Thermal Conductivity of Fluids. Nitric Oxide.

The thermal properties of high-voltage insulants

Lack of agreement between published values of the thermal properties of high-voltage insulants necessitates the development of relatively simple methods for their measurement. Transient methods for the determination of the thermal diffusivity of solids and thermal conductivity of fluids are described, with examples of their use and an estimate of their accuracy. Allowance is made for anisotropy in the case of solids. Suitable methods for determination of specific heat are discussed, and the importance of the rate of change of density of liquids with temperature is stressed.

Closure to “Discussion of ‘New Method to Measure Prandtl Number and Thermal Conductivity of Fluids’” (1957, ASME J. Appl. Mech., 24, p. 631)

Closure to “Discussion of ‘New Method to Measure Prandtl Number and Thermal Conductivity of Fluids’” (1957, ASME J. Appl. Mech., 24, p. 631)