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Heikki Lihavainen - One of the best experts on this subject based on the ideXlab platform.
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homogeneous nucleation rate measurements of 1 butanol in helium a comparative study of a thermal diffusion cloud chamber and a Laminar Flow diffusion chamber
Journal of Chemical Physics, 2005Co-Authors: David Brus, Vladimír Ždímal, A P Hyvarinen, Heikki LihavainenAbstract:Isothermal homogeneous nucleation rates of 1-butanol were measured both in a thermal diffusion cloud chamber and in a Laminar Flow diffusion chamber built recently at the Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic, Prague, Czech Republic. The chosen system 1-butanol-helium can be studied reasonably well in both devices, in the overlapping range of temperatures. The results were compared with those found in the literature and those measured by Lihavainen in a Laminar Flow diffusion chamber of a similar design. The same isotherms measured with the thermal diffusion cloud chamber occur at highest saturation ratios of the three devices. Isotherms measured with the two Laminar Flow diffusion chambers are reasonably close together; the measurements by Lihavainen occur at lowest saturation ratios. The temperature dependences observed were similar in all three devices. The molecular content of critical clusters was calculated using the nucleation theorem and compared wit...
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homogeneous nucleation rate measurements of 1 butanol in helium a comparative study of a thermal diffusion cloud chamber and a Laminar Flow diffusion chamber
Journal of Chemical Physics, 2005Co-Authors: David Brus, Vladimír Ždímal, A P Hyvarinen, Heikki LihavainenAbstract:Isothermal homogeneous nucleation rates of 1-butanol were measured both in a thermal diffusion cloud chamber and in a Laminar Flow diffusion chamber built recently at the Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic, Prague, Czech Republic. The chosen system 1-butanol-helium can be studied reasonably well in both devices, in the overlapping range of temperatures. The results were compared with those found in the literature and those measured by Lihavainen in a Laminar Flow diffusion chamber of a similar design. The same isotherms measured with the thermal diffusion cloud chamber occur at highest saturation ratios of the three devices. Isotherms measured with the two Laminar Flow diffusion chambers are reasonably close together; the measurements by Lihavainen occur at lowest saturation ratios. The temperature dependences observed were similar in all three devices. The molecular content of critical clusters was calculated using the nucleation theorem and compared with the Kelvin equation. Both Laminar Flow diffusion chambers provided very similar sizes slightly above the Kelvin equation, whereas the thermal diffusion cloud chamber suggests critical cluster sizes significantly smaller. The results found elsewhere in the literature were in reasonable agreement with our results.
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homogeneous nucleation of n pentanol in a Laminar Flow diffusion chamber
NUCLEATION AND ATMOSPHERIC AEROSOLS 2000: 15th International Conference, 2001Co-Authors: Heikki Lihavainen, Y Viisanen, Markku KulmalaAbstract:As a contribution to the Joint Experiment on Homogenous Nucleation, a version of a Laminar Flow diffusion chamber was developed for nucleation rate measurements. The design and operational characteristics of the chamber will be presented. Homogenous nucleation rates of n-pentanol were measured as a function of saturation ratio in the temperature range between 260 K and 290 K. The results were compared to the classical nucleation theory. The experimental results were three orders of magnitudes higher than the theoretical predictions. The difference was almost constant over the whole temperature range. The results were compared with results from other experimental devices, they were in good agreement at lower temperatures.
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Homogenous nucleation of n-butanol in Laminar Flow diffusion chamber
Journal of Aerosol Science, 2000Co-Authors: Heikki Lihavainen, Y ViisanenAbstract:In this study Laminar Flow diffusion chamber was developed to measure homogeneous nucleation rates as a function of saturation and temperature. n-Butanol was chosen for nucleating vapor because its thermodynamic properties are well known.
Sujoy Kumar Saha - One of the best experts on this subject based on the ideXlab platform.
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thermohydraulics of Laminar Flow through a circular tube having integral helical corrugations and fitted with helical screw tape insert
Chemical Engineering Communications, 2013Co-Authors: Sujoy Kumar SahaAbstract:The experimental friction factor and Nusselt number data for Laminar Flow through a circular duct having integral helical corrugations and fitted with a helical screw-tape insert are presented. Predictive friction factor and Nusselt number correlations are also presented. The thermohydraulic performance was evaluated. The major findings of this experimental investigation are that the helical screw-tape insert in combination with integral helical corrugations performs significantly better than the individual enhancement technique acting alone for Laminar Flow through a circular duct up to a certain value of the fin parameter. This research finding is useful in designing tubes carrying solar thermal mass of viscous oil in a parabolic trough solar collector used in environmentally sound and increasingly cost-effective solar thermal electric power plants. The result is also useful in designing heat exchangers used in process industries.
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Laminar Flow heat transfer enhancement in a circular tube having integral transverse rib roughness and fitted with centre cleared twisted tape
Experimental Thermal and Fluid Science, 2013Co-Authors: Suvanjan Bhattacharyya, Subhankar Saha, Sujoy Kumar SahaAbstract:Abstract The experimental friction factor and Nusselt number data for Laminar Flow through a circular duct having integral transverse ribs and fitted with centre-cleared twisted-tape have been presented. Predictive friction factor and Nusselt number correlations have also been presented. The thermohydraulic performance has been evaluated. The major findings of this experimental investigation are that the centre-cleared twisted tapes in combination with transverse ribs perform significantly better than the individual enhancement technique acting alone for Laminar Flow through a circular duct up to a certain amount of centre-clearance. This result is useful for the design of solar thermal heaters and heat exchangers.
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thermohydraulics of Laminar Flow through a circular tube having integral helical rib roughness and fitted with centre cleared twisted tape
Experimental Thermal and Fluid Science, 2012Co-Authors: Suvanjan Bhattacharyya, Sujoy Kumar SahaAbstract:Abstract The experimental friction factor and Nusselt number data for Laminar Flow through a circular duct having integral helical rib roughness and fitted with centre-cleared twisted-tape have been presented. Predictive friction factor and Nusselt number correlations have also been presented. The thermohydraulic performance has been evaluated. The major findings of this experimental investigation are that the centre-cleared twisted tapes in combination with integral helical rib roughness perform significantly better than the individual enhancement technique acting alone for Laminar Flow through a circular duct up to a certain amount of twisted-tape centre-clearance.
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thermohydraulics of Laminar Flow of viscous oil through a circular tube having integral axial rib roughness and fitted with center cleared twisted tape
Experimental Thermal and Fluid Science, 2012Co-Authors: Sujoy Kumar Saha, Suvanjan Bhattacharyya, Pranab Kumar PalAbstract:Abstract The experimental friction factor and Nusselt number data for Laminar Flow through a circular duct having integral axial rib roughness and fitted with center-cleared twisted-tape have been presented. Predictive friction factor and Nusselt number correlations have also been presented. The thermohydraulic performance has been evaluated. The major findings of this experimental investigation are that with and without center-cleared twisted tapes in combination with integral axial rib roughness perform significantly better than the individual enhancement technique acting alone for Laminar Flow through a circular duct up to a certain amount of twisted-tape center-clearance.
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thermohydraulics of Laminar Flow of viscous oil through a circular tube having axial corrugations and fitted with centre cleared twisted tape
Experimental Thermal and Fluid Science, 2012Co-Authors: Sujoy Kumar SahaAbstract:Abstract The experimental friction factor and Nusselt number data for Laminar Flow through a circular duct having axial corrugation and fitted with centre-cleared twisted-tape have been presented. Predictive friction factor and Nusselt number correlations have also been presented. The thermohydraulic performance has been evaluated. The major findings of this experimental investigation are that the centre-cleared twisted tapes in combination with axial corrugation perform better than the individual enhancement technique acting alone for Laminar Flow through a circular duct up to a certain amount of centre-clearance.
Y Viisanen - One of the best experts on this subject based on the ideXlab platform.
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a Laminar Flow diffusion chamber for homogeneous nucleation studies
Journal of Physical Chemistry B, 2001Co-Authors: Y ViisanenAbstract:A new version of Laminar Flow diffusion chamber was developed for unary homogeneous nucleation from vapor to liquid studies. The developed Laminar Flow diffusion chamber can quantitatively measure nucleation rates as a function of saturation ratio and temperature. A numerical model was developed for calculations of temperature and saturation ratio profiles inside the Laminar Flow diffusion chamber. Several experiments were made to ensure the proper and reliable operation of the device and the numerical model. Nucleation rates of n-hexanol were measured using helium as a carrier gas from 265.0 to 295.0 K. The measured nucleation rate range was from 103 to 107 cm-3 s-1. Temperature and saturation ratio dependencies were compared to the classical nucleation theory. The saturation ratio dependency was well predicted by the theory. Results were compared to the measurements made by others. They were in reasonable agreement at the lower end of the temperature range of this study. The carrier gas effect was also ...
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homogeneous nucleation of n pentanol in a Laminar Flow diffusion chamber
NUCLEATION AND ATMOSPHERIC AEROSOLS 2000: 15th International Conference, 2001Co-Authors: Heikki Lihavainen, Y Viisanen, Markku KulmalaAbstract:As a contribution to the Joint Experiment on Homogenous Nucleation, a version of a Laminar Flow diffusion chamber was developed for nucleation rate measurements. The design and operational characteristics of the chamber will be presented. Homogenous nucleation rates of n-pentanol were measured as a function of saturation ratio in the temperature range between 260 K and 290 K. The results were compared to the classical nucleation theory. The experimental results were three orders of magnitudes higher than the theoretical predictions. The difference was almost constant over the whole temperature range. The results were compared with results from other experimental devices, they were in good agreement at lower temperatures.
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Homogenous nucleation of n-butanol in Laminar Flow diffusion chamber
Journal of Aerosol Science, 2000Co-Authors: Heikki Lihavainen, Y ViisanenAbstract:In this study Laminar Flow diffusion chamber was developed to measure homogeneous nucleation rates as a function of saturation and temperature. n-Butanol was chosen for nucleating vapor because its thermodynamic properties are well known.
David Brus - One of the best experts on this subject based on the ideXlab platform.
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homogeneous nucleation rate measurements of 1 butanol in helium a comparative study of a thermal diffusion cloud chamber and a Laminar Flow diffusion chamber
Journal of Chemical Physics, 2005Co-Authors: David Brus, Vladimír Ždímal, A P Hyvarinen, Heikki LihavainenAbstract:Isothermal homogeneous nucleation rates of 1-butanol were measured both in a thermal diffusion cloud chamber and in a Laminar Flow diffusion chamber built recently at the Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic, Prague, Czech Republic. The chosen system 1-butanol-helium can be studied reasonably well in both devices, in the overlapping range of temperatures. The results were compared with those found in the literature and those measured by Lihavainen in a Laminar Flow diffusion chamber of a similar design. The same isotherms measured with the thermal diffusion cloud chamber occur at highest saturation ratios of the three devices. Isotherms measured with the two Laminar Flow diffusion chambers are reasonably close together; the measurements by Lihavainen occur at lowest saturation ratios. The temperature dependences observed were similar in all three devices. The molecular content of critical clusters was calculated using the nucleation theorem and compared wit...
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homogeneous nucleation rate measurements of 1 butanol in helium a comparative study of a thermal diffusion cloud chamber and a Laminar Flow diffusion chamber
Journal of Chemical Physics, 2005Co-Authors: David Brus, Vladimír Ždímal, A P Hyvarinen, Heikki LihavainenAbstract:Isothermal homogeneous nucleation rates of 1-butanol were measured both in a thermal diffusion cloud chamber and in a Laminar Flow diffusion chamber built recently at the Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic, Prague, Czech Republic. The chosen system 1-butanol-helium can be studied reasonably well in both devices, in the overlapping range of temperatures. The results were compared with those found in the literature and those measured by Lihavainen in a Laminar Flow diffusion chamber of a similar design. The same isotherms measured with the thermal diffusion cloud chamber occur at highest saturation ratios of the three devices. Isotherms measured with the two Laminar Flow diffusion chambers are reasonably close together; the measurements by Lihavainen occur at lowest saturation ratios. The temperature dependences observed were similar in all three devices. The molecular content of critical clusters was calculated using the nucleation theorem and compared with the Kelvin equation. Both Laminar Flow diffusion chambers provided very similar sizes slightly above the Kelvin equation, whereas the thermal diffusion cloud chamber suggests critical cluster sizes significantly smaller. The results found elsewhere in the literature were in reasonable agreement with our results.
Suvanjan Bhattacharyya - One of the best experts on this subject based on the ideXlab platform.
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Laminar Flow heat transfer enhancement in a circular tube having integral transverse rib roughness and fitted with centre cleared twisted tape
Experimental Thermal and Fluid Science, 2013Co-Authors: Suvanjan Bhattacharyya, Subhankar Saha, Sujoy Kumar SahaAbstract:Abstract The experimental friction factor and Nusselt number data for Laminar Flow through a circular duct having integral transverse ribs and fitted with centre-cleared twisted-tape have been presented. Predictive friction factor and Nusselt number correlations have also been presented. The thermohydraulic performance has been evaluated. The major findings of this experimental investigation are that the centre-cleared twisted tapes in combination with transverse ribs perform significantly better than the individual enhancement technique acting alone for Laminar Flow through a circular duct up to a certain amount of centre-clearance. This result is useful for the design of solar thermal heaters and heat exchangers.
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thermohydraulics of Laminar Flow through a circular tube having integral helical rib roughness and fitted with centre cleared twisted tape
Experimental Thermal and Fluid Science, 2012Co-Authors: Suvanjan Bhattacharyya, Sujoy Kumar SahaAbstract:Abstract The experimental friction factor and Nusselt number data for Laminar Flow through a circular duct having integral helical rib roughness and fitted with centre-cleared twisted-tape have been presented. Predictive friction factor and Nusselt number correlations have also been presented. The thermohydraulic performance has been evaluated. The major findings of this experimental investigation are that the centre-cleared twisted tapes in combination with integral helical rib roughness perform significantly better than the individual enhancement technique acting alone for Laminar Flow through a circular duct up to a certain amount of twisted-tape centre-clearance.
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thermohydraulics of Laminar Flow of viscous oil through a circular tube having integral axial rib roughness and fitted with center cleared twisted tape
Experimental Thermal and Fluid Science, 2012Co-Authors: Sujoy Kumar Saha, Suvanjan Bhattacharyya, Pranab Kumar PalAbstract:Abstract The experimental friction factor and Nusselt number data for Laminar Flow through a circular duct having integral axial rib roughness and fitted with center-cleared twisted-tape have been presented. Predictive friction factor and Nusselt number correlations have also been presented. The thermohydraulic performance has been evaluated. The major findings of this experimental investigation are that with and without center-cleared twisted tapes in combination with integral axial rib roughness perform significantly better than the individual enhancement technique acting alone for Laminar Flow through a circular duct up to a certain amount of twisted-tape center-clearance.
