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1.
Artigo em Inglês | MEDLINE | ID: mdl-31080299

RESUMO

This paper presents a new wide-ranging correlation for the thermal conductivity of n-hexadecane based on critically evaluated experimental data. The correlation is designed to be used with a recently published equation of state, and it is valid from the triple point up to 700 K and pressures up to 50 MPa. We estimate the uncertainty at a 95% confidence level to be 4% over the aforementioned range, with the exception of the dilute-gas range where the uncertainty is 2.7% over the temperature range 583 to 654 K. The correlation behaves in a physically reasonable manner when extrapolated to the full range of the equation of state, but the uncertainties are larger outside of the validated range, and also in the critical region.

2.
Artigo em Inglês | MEDLINE | ID: mdl-31092958

RESUMO

This paper presents a new wide-ranging correlation for the viscosity of ammonia based on critically evaluated experimental data. The correlation is designed to be used with a recently developed equation of state, and it is valid from the triple point to 725 K, at pressures up to 50 MPa. The estimated uncertainty varies depending on the temperature and pressure, from 0.6% to 5%. The correlation behaves in a physically reasonable manner when extrapolated to 100 MPa, however care should be taken when using the correlations outside of the validated range.

3.
Artigo em Inglês | MEDLINE | ID: mdl-30983644

RESUMO

The available experimental data for the thermal conductivity of 13 inorganic molten salts have been critically examined with the intention of establishing thermal conductivity reference correlations. All experimental data have been categorized into primary and secondary data according to the quality of measurement specified by a series of criteria. Standard reference correlations are proposed for the following molten salts (with estimated uncertainties at the 95 % confidence level given in parentheses): LiNO3 (7 %), NaNO3 (7 %), KNO3 (15 %), NaBr (15 %), KBr (15 %), RbBr (15 %), LiCl (17 %), NaCl (20 %), KCl (17 %), RbCl (17%), CsCl (10 %), NaI (17 %), and RbI (20 %).

4.
Artigo em Inglês | MEDLINE | ID: mdl-30996494

RESUMO

In this paper, reference values and reference correlations for the thermal conductivity and viscosity of pure fluids are reviewed. Reference values and correlations for the thermal conductivity and the viscosity of pure fluids provide thoroughly evaluated data or functional forms and serve to help calibrate instruments, validate or extend models, and underpin some commercial transactions or designs, among other purposes. The criteria employed for the selection of thermal conductivity and viscosity reference values are also discussed; such values, which have the lowest uncertainties currently achievable, are typically adopted and promulgated by international bodies. Similar criteria are employed in the selection of reference correlations, which cover a wide range of conditions, and are often characterized by low uncertainties in their ranges of definition.

5.
J Phys Chem Ref Data ; 46(3)2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29230074

RESUMO

This paper presents new wide-ranging correlations for the viscosity and thermal conductivity of n-undecane based on critically evaluated experimental data. The correlations are designed to be used with a recently published equation of state that is valid from the triple point to 700 K, at pressures up to 500 MPa, with densities below 776.86 kg m-3. The estimated uncertainty for the dilute-gas viscosity is 2.4%, and the estimated uncertainty for viscosity in the liquid phase for pressures up to 60 MPa over the temperature range 260 K to 520 K is 5%. The estimated uncertainty is 3% for the thermal conductivity of the low-density gas, and 3% for the liquid over the temperature range from 284 K to 677 K at pressures up to 400 MPa. Both correlations behave in a physically reasonable manner when extrapolated to the full range of the equation of state, however care should be taken when using the correlations outside of the validated range. The uncertainties will be larger outside of the validated range, and also in the critical region.

6.
J Phys Chem Ref Data ; 46(3)2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28970643

RESUMO

The available experimental data for the thermal conductivity of liquid bismuth, cobalt, germanium and silicon have been critically examined with the intention of establishing thermal conductivity reference correlations. All experimental data have been categorized into primary and secondary data according to the quality of measurement specified by a series of criteria. The proposed standard reference correlations for the thermal conductivity of liquid bismuth, cobalt, germanium, and silicon are respectively characterized by uncertainties of 10, 15, 16 and 9.5% at the 95% confidence level.

7.
J Phys Chem Ref Data ; 46(2)2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28785120

RESUMO

This paper presents new wide-ranging correlations for the viscosity and thermal conductivity of ethyl fluoride (R161) based on critically evaluated experimental data. The correlations are designed to be used with a recently published equation of state that is valid from 130 K to 450 K, at pressures up to 100 MPa. The estimated uncertainty at a 95% confidence level is 2% for the viscosity of low-density gas (pressures below 0.5 MPa), and 3% for the viscosity of the liquid over the temperature range from 243 K to 363 K at pressures up to 30 MPa. The estimated uncertainty is 3% for the thermal conductivity of the low-density gas, and 3% for the liquid over the temperature range from 234 K to 374 K at pressures up to 20 MPa. Both correlations may be used over the full range of the equation of state, but the uncertainties will be larger, especially in the critical region.

8.
J Phys Chem Ref Data ; 46(1)2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28584386

RESUMO

New, wide-range reference equations for the thermal conductivity of cyclohexane as a function of temperature and density are presented. 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. We estimate the uncertainty (at the 95% confidence level) for the thermal conductivity of cyclohexane from the triple point (279.86 K) to 650 K at pressures up to 175 MPa to be 4% for the compressed liquid and supercritical phases. For the low-pressure gas phase (up to 0.1 MPa) over the temperature range 280 K to 680 K, the estimated uncertainty is 2.5%. Uncertainties in the critical region are much larger, since the thermal conductivity approaches infinity at the critical point and is very sensitive to small changes in density.

9.
J Phys Chem Ref Data ; 45(3)2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27818536

RESUMO

New, wide-range reference equations for the thermal conductivity of ethene and propene as a function of temperature and density are presented. 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. For ethene, we estimate the uncertainty (at the 95% confidence level) for the thermal conductivity from 110 K to 520 K at pressures up to 200 MPa to be 5% for the compressed liquid and supercritical phases. For the low-pressure gas phase (to 0.1 MPa) over the temperature range 270 K to 680 K, the estimated uncertainty is 4%. The correlation is valid from 110 K to 680 K and up to 200 MPa, but it behaves in a physically reasonable manner down to the triple point and may be used at pressures up to 300 MPa, although the uncertainty will be larger in regions where experimental data were unavailable. In the case of propene, data are much more limited. We estimate the uncertainty for the thermal conductivity of propene from 180 K to 625 K at pressures up to 50 MPa to be 5% for the gas, liquid, and supercritical phases. The correlation is valid from 180 K to 625 K and up to 50 MPa, but it behaves in a physically reasonable manner down to the triple point and may be used at pressures up to 100 MPa, although the uncertainty will be larger in regions where experimental data were unavailable. For both fluids, uncertainties in the critical region are much larger, since the thermal conductivity approaches infinity at the critical point and is very sensitive to small changes in density.

10.
J Phys Chem Ref Data ; 45(1)2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27064300

RESUMO

This paper contains new, representative reference equations for the thermal conductivity of carbon dioxide. 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, we incorporated recent theoretical calculations 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 1100 K and pressures up to 200 MPa. The overall uncertainty (at the 95% confidence level) of the proposed correlation varies depending on the state point from a low of 1% at very low pressures below 0.1 MPa between 300 K and 700 K, to 5% at the higher pressures of the range of validity.

11.
J Hazard Mater ; 261: 653-68, 2013 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-23995562

RESUMO

This paper addresses the current important problem of modelling the dispersion of toxic gases released in the urban terrains (i.e. neighbourhood scale) by the Detached Eddy Simulation (DES). This approach is a resolution that lays between the Reynolds Averaged Navier-Stokes and Large Eddy Simulation models and focuses especially on establishing a better balance between efficiency and accuracy. Herein are presented the theoretical approach of a new model, which is based on the DES and the Spalart-Almaras turbulent closure and a number of validation tests like the flow and the dispersion over and around a single building and an array of buildings. Overall, employed validation metrics were within the acceptable limits and the model demonstrated an acceptable agreement with the experimental datasets which confirms the use of this approach for the modelling and dispersion of gases in complex terrains like a city.


Assuntos
Poluentes Atmosféricos , Modelos Teóricos , Movimentos do Ar , Cidades , Gases
12.
Environ Technol ; 32(5-6): 593-608, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21877540

RESUMO

Industrial activities are sources of high emission rates of particulate matter. The existence of many such industrial plants close to a densely populated area can have a severe effect on human health. The effects can be even worse when these emissions are added to existing background concentration levels. This study deals with the assessment of the primary particulate matter pollution caused by industrial activities close to the city of Thessaloniki in Greece. An atmospheric dispersion and regulatory model was employed, i.e. AERMOD from the US Environmental Pollution Agency. A new PM10 emission sources inventory was prepared for the main industrial plants of the area and the annual and monthly average concentrations from 2003 to 2007 were calculated. The results from AERMOD were validated against data from available monitoring stations and showed reasonably good agreement. It was estimated that industry contributes approximately 30% of primary PM10 on the western suburbs of the city and about 7% in the city centre. The effect of the wind direction was also studied and it was illustrated that the frequent southwest winds present higher concentration levels than the strong north ones.


Assuntos
Indústrias , Modelos Estatísticos , Material Particulado/análise , Cidades , Geografia , Grécia , Estações do Ano , Tempo (Meteorologia)
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