Showing papers by "Marc J. Assael published in 2013"

Reference Correlation of the Viscosity of n-Heptane from the Triple Point to 600 K and up to 248 MPa

Abstract: This paper contains a new wide-ranging correlation for the viscosity of n-heptane based on critically evaluated experimental data. The correlation is valid from the triple point (182.55 K) to 600 K, and at pressures up to 248 MPa. The estimated uncertainty at a 95% confidence level is 3.5% over the whole range (with the exception of the near-critical region). Along the saturated liquid curve, the estimated uncertainty is 1% below 292 K, 0.6% in the region from 292 to 346 K, rising to 2% between 346 and 363 K, and 0.3% for the low-density gas at temperatures from 317 to 600 K and pressures to 0.3 MPa.

Reference Correlation of the Thermal Conductivity of Toluene from the Triple Point to 1000 K and up to 1000 MPa

Abstract: This paper contains new, representative reference equations for the thermal conductivity of n-hexane. The equations are based in part upon a body of experimental data that has been critically assessed for internal consistency and for agreement with theory whenever possible. In the case of the dilute-gas thermal conductivity, a theoretically based correlation was adopted in order to extend the temperature range of the experimental data. Moreover, in the critical region, the experimentally observed enhancement of the thermal conductivity is well represented by theoretically based equations containing just one adjustable parameter. The correlations are applicable for the temperature range from the triple point to 600 K and pressures up to 500 MPa. The overall uncertainty (considered to be estimates of a combined expanded uncertainty with a coverage factor of 2) of the proposed correlation is estimated, for pressures less than 500 MPa and temperatures less than 600 K, to be less than 6%.

Reference Correlation of the Viscosity of Squalane from 273 to 373 K at 0.1 MPa

Abstract: The paper presents a new reference correlation for the viscosity of squalane at 0.1 MPa. The correlation should be valuable as it is the first to cover a moderately high viscosity range, from 3 to 118 mPa s. It is based on new viscosity measurements carried out for this work, as well as other critically evaluated experimental viscosity data from the literature. The correlation is valid from 273 to 373 K at 0.1 MPa. The average absolute percentage deviation of the fit is 0.67, and the expanded uncertainty, with a coverage factor k = 2, is 1.5%.

Reference Correlation of the Thermal Conductivity of Methanol from the Triple Point to 660 K and up to 245 MPa

Abstract: This paper contains new, representative reference equations for the thermal conductivity of methanol. The equations are based in part upon a body of experimental data that has been critically assessed for internal consistency and for agreement with theory whenever possible. In the case of the dilute-gas thermal conductivity, a theoretically based correlation was adopted in order to extend the temperature range of the experimental data. Moreover, in the critical region, the experimentally observed enhancement of the thermal conductivity is well represented by theoretically based equations containing just one adjustable parameter. The correlation is applicable for the temperature range from the triple point to 660 K and pressures up to 245 MPa. The overall uncertainty (at the 95% confidence level) of the correlation over its range of applicability for the liquid and supercritical phases, excluding the critical region, is estimated to be less than 4.4%. The dilute gas region has an estimated uncertainty of 3%, and the liquid at atmospheric pressure is represented to 2%. Uncertainty in regions where data are unavailable for comparison, such as the dense gas region, may be larger.

Transport Properties of Fluids

Abstract: Transport processes are the processes whereby mass, energy, or momentum are transported from one region of a material to another under the influence of gradients of velocity, temperature, or composition. They are characterized respectively by viscosity, thermal conductivity and diffusion coefficients, and their introduction forms the first part of this chapter. A brief discussion of the molecular theory describes what is known and what can be predicted. Accurate measurements are necessary and therefore current techniques are briefly presented. The chapter is concluded with a discussion of current reference values for the viscosity, thermal conductivity and diffusion coefficients employed for the calibration of instruments.

A novel vibrating-wire viscometer for high-viscosity liquids at moderate pressures

Abstract: The design and operation of a new vibrating-wire viscometer for the measurement of high-viscosity liquids (50 to 125) mPa·s, and up to 18 MPa are described. The design of the instrument is based on a complete theory so that it is possible to make absolute measurements. The viscosity of liquid diisodecyl phthalate (DIDP) is measured at temperatures between (293 and 363) K and pressures between (0.1 and 18) MPa with an absolute uncertainty of ± 1.5 %.

Measurements of the Viscosity of Bis(2-ethylhexyl) Sebacate, Squalane, and Bis(2-ethylhexyl) Phthalate between (283 and 363) K at 0.1 MPa

Abstract: New measurements of the viscosity of bis(2-ethylhexyl) sebacate, squalane, and bis(2-ethylhexyl) phthalate at temperatures between (283 and 363) K at 0.1 MPa are presented. These liquids are being examined as possible industrial reference fluids for moderately high viscosity. The measurements of these three moderately viscous liquids were performed in a recently developed new vibrating-wire viscometer with an absolute expanded uncertainty of ±1.5 %. The measurements were fitted to an Arrhenius-type equation with an overall uncertainty of 0.43 %, 0.84 %, and 0.56 % (at the 95 % confidence level), respectively.

H15-117: Application of detached eddy simulation to neighborhood scale atmospheric dispersion

Abstract: Present work addresses the current important problem of modelling the dispersion of toxic gases (i.e. the wind field prognosis) released in the urban terrain or neighbourhood scale by a new for the area approach, the Detached Eddy Simulation. In this scale, both Fast Approximate (FAMs) and Fully Computational Models (FCMs) have been tested, while none of these models’ categories can prevail over the other. Nevertheless, the FCMs are continuously becoming more user-friendly and approachable to the communities of researchers and decision-makers even though their use demands of high computational power and qualified personnel. Most often, such models are based on the Reynolds Average Navier-Stokes equations (RANS) and the Large Eddy Simulation approach (LES). Unfortunately, both methods result either to less accurate or most computationally expensive models. Therefore, it is necessary to seek a resolution that is intermediate between the RANS and LES models in order to find a better balance between efficiency and accuracy, like the hybrid RANS/LES or the DES models like the one in this work. Herein, a new model is presented, that is able to estimate the initial conditions of the source (e.g. a small explosion), as well as provide the needed spatial pattern of wind statistics and ultimately calculate the atmospheric dispersion of the gas. The model is utilizing the Detached Eddy Simulation approach, in conjunction with the one-equation turbulent Spalart-Allmaras method, in the problem of atmospheric dispersion. To implement this model, a new software called the Prognostic Model for Toxic Gases Dispersion was developed and is described here. Several selected software evaluation test cases have been conducted and compared with cases found in the literature using a set of proposed model acceptance criteria. In this paper some of this cases are presented.