The Experts below are selected from a list of 47481 Experts worldwide ranked by ideXlab platform
Pascual Alvarez Gomez - One of the best experts on this subject based on the ideXlab platform.
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experimental test for the estimation of the Evaporation Rate in indoor swimming pools validation of a new cfd based simulation methodology
Building and Environment, 2018Co-Authors: Juan Luis Foncubierta Blazquez, Ismael Rodriguez Maestre, Francisco Javier Gonzalez Gallero, Pascual Alvarez GomezAbstract:Abstract The aim of this work is to present an experimental procedure at laboratory scale that was developed to validate a new CFD-based methodology for the estimation of water Evaporation Rate in indoor swimming pools, under a wide range of convective flow conditions (36 experiments) and focussing on the most common operation conditions of these facilities: low air mean velocities (0.08–0.24 m/s), and water and air temperatures in the ranges 24-28 °C and 26-30 °C, respectively. One of the main hypotheses of the simulation methodology set a free slip wall condition (no shear stress) at the air-water interface, based on the fact that the dynamic boundary layer depth will be smaller than the thickness of the thermal and humidity boundary layers in this kind of flows. The comparison between simulated and experimental results show that the modelling stRategy proposed is a promising tool, with average relative errors of 9% for the typical mixed convection flows in indoor swimming pools.
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a new practical cfd based methodology to calculate the Evaporation Rate in indoor swimming pools
Energy and Buildings, 2017Co-Authors: Juan Luis Foncubierta Blazquez, Ismael Rodriguez Maestre, Francisco Javier Gonzalez Gallero, Pascual Alvarez GomezAbstract:Abstract This paper presents a new methodology in which a computational fluid dynamics model is applied to estimate water Evaporation Rate in indoor swimming pools. This Rate is needed to achieve a suitable energy performance of ventilation and dehumidification systems. The main hypotheses of the model set the following boundary conditions at the air-water interface: air temperature equal to water temperature, water vapour concentration equal to saturation humidity of air at water temperature and free slip wall condition (no shear stress). This last condition can be justified by the fact that Prandtl and Schmidt turbulent numbers are usually less than one in this kind of flows. Consequently, the dynamic boundary layer depth will be smaller than the thickness of the thermal and humidity boundary layers. The model was experimentally validated by using data from three different test chambers and from a real swimming-pool. A total of 233 different flow conditions were simulated. The results were quite satisfactory, with a relative error of only 3% in the simulations of the real swimming-pool and a total average relative error smaller than 9%.
Cyril Crua - One of the best experts on this subject based on the ideXlab platform.
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change of Evaporation Rate of single monocomponent droplet with temperature using time resolved phase rainbow refractometry
Proceedings of the Combustion Institute, 2019Co-Authors: Yingchun Wu, Lutz Mädler, Xuecheng Wu, Gerard Grehan, Haipeng Li, Cyril CruaAbstract:Abstract Droplet Evaporation characterization, although of great significance, is still challenging. The recently developed phase rainbow refractometry (PRR) is proposed as an approach to measuring the droplet temperature, size as well as Evaporation Rate simultaneously, and is applied to a single flowing n-heptane droplet produced by a droplet-on-demand generator. The changes of droplet temperature and Evaporation Rate after a transient spark heating are reflected in the time-resolved PRR image. Results show that droplet Evaporation Rate increases with temperature, from −1.28 × 10 − 8 m2/s at atmospheric 293 K to a range of (−1.5, −8) × 10 − 8 m2/s when heated to (294, 315) K, agreeing well with the Maxwell and Stefan–Fuchs model predictions. Uncertainty analysis suggests that the main source is the indeterminate gradient inside droplet, resulting in an underestimation of droplet temperature and Evaporation Rate. With the demonstration on simultaneous measurements of droplet refractive index as well as droplet transient and local Evaporation Rate in this work, PRR is a promising tool to investigate single droplet Evaporation in real engine conditions.
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simultaneous measurement of monocomponent droplet temperature refractive index size and Evaporation Rate with phase rainbow refractometry
Journal of Quantitative Spectroscopy & Radiative Transfer, 2018Co-Authors: Yingchun Wu, Cyril Crua, Lutz Mädler, Sawitree Saengkaew, Xuecheng Wu, Haipeng Li, Gerard GrehanAbstract:Abstract The accuRate measurements of droplet temperature, size and Evaporation Rate are of great importance to characterize the heat and mass transfer during Evaporation/condensation processes. The nanoscale size change of a micron-sized droplet exactly describes its transient mass transfer, but is difficult to measure because it is smaller than the resolutions of current size measurement techniques. The Phase Rainbow Refractometry (PRR) technique is developed and applied to measure droplet temperature, size and transient size changes and thereafter Evaporation Rate simultaneously. The measurement principle of PRR is theoretically derived, and it reveals that the phase shift of the time-resolved ripple structures linearly depends on, and can directly yield, nano-scale size changes of droplets. The PRR technique is first verified through the simulation of rainbows of droplets with changing size, and results show that PRR can precisely measure droplet refractive index, absolute size, as well as size change with absolute and relative errors within several nanometers and 0.6%, respectively, and thus PRR permits accuRate measurements of transient droplet Evaporation Rates. The Evaporations of flowing single n-nonane droplet and mono-dispersed n-heptane droplet stream are investigated by two PRR systems with a high speed linear CCD and a low speed array CCD, respectively. Their transient Evaporation Rates are experimentally determined and quantitatively agree well with the theoretical values predicted by classical Maxwell and Stefan–Fuchs models. With the demonstration of Evaporation Rate measurement of monocomponent droplet in this work, PRR is an ideal tool for measurements of transient droplet Evaporation/condensation processes, and can be extended to multicomponent droplets in a wide range of industrially-relevant applications.
Gerard Grehan - One of the best experts on this subject based on the ideXlab platform.
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change of Evaporation Rate of single monocomponent droplet with temperature using time resolved phase rainbow refractometry
Proceedings of the Combustion Institute, 2019Co-Authors: Yingchun Wu, Lutz Mädler, Xuecheng Wu, Gerard Grehan, Haipeng Li, Cyril CruaAbstract:Abstract Droplet Evaporation characterization, although of great significance, is still challenging. The recently developed phase rainbow refractometry (PRR) is proposed as an approach to measuring the droplet temperature, size as well as Evaporation Rate simultaneously, and is applied to a single flowing n-heptane droplet produced by a droplet-on-demand generator. The changes of droplet temperature and Evaporation Rate after a transient spark heating are reflected in the time-resolved PRR image. Results show that droplet Evaporation Rate increases with temperature, from −1.28 × 10 − 8 m2/s at atmospheric 293 K to a range of (−1.5, −8) × 10 − 8 m2/s when heated to (294, 315) K, agreeing well with the Maxwell and Stefan–Fuchs model predictions. Uncertainty analysis suggests that the main source is the indeterminate gradient inside droplet, resulting in an underestimation of droplet temperature and Evaporation Rate. With the demonstration on simultaneous measurements of droplet refractive index as well as droplet transient and local Evaporation Rate in this work, PRR is a promising tool to investigate single droplet Evaporation in real engine conditions.
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simultaneous measurement of monocomponent droplet temperature refractive index size and Evaporation Rate with phase rainbow refractometry
Journal of Quantitative Spectroscopy & Radiative Transfer, 2018Co-Authors: Yingchun Wu, Cyril Crua, Lutz Mädler, Sawitree Saengkaew, Xuecheng Wu, Haipeng Li, Gerard GrehanAbstract:Abstract The accuRate measurements of droplet temperature, size and Evaporation Rate are of great importance to characterize the heat and mass transfer during Evaporation/condensation processes. The nanoscale size change of a micron-sized droplet exactly describes its transient mass transfer, but is difficult to measure because it is smaller than the resolutions of current size measurement techniques. The Phase Rainbow Refractometry (PRR) technique is developed and applied to measure droplet temperature, size and transient size changes and thereafter Evaporation Rate simultaneously. The measurement principle of PRR is theoretically derived, and it reveals that the phase shift of the time-resolved ripple structures linearly depends on, and can directly yield, nano-scale size changes of droplets. The PRR technique is first verified through the simulation of rainbows of droplets with changing size, and results show that PRR can precisely measure droplet refractive index, absolute size, as well as size change with absolute and relative errors within several nanometers and 0.6%, respectively, and thus PRR permits accuRate measurements of transient droplet Evaporation Rates. The Evaporations of flowing single n-nonane droplet and mono-dispersed n-heptane droplet stream are investigated by two PRR systems with a high speed linear CCD and a low speed array CCD, respectively. Their transient Evaporation Rates are experimentally determined and quantitatively agree well with the theoretical values predicted by classical Maxwell and Stefan–Fuchs models. With the demonstration of Evaporation Rate measurement of monocomponent droplet in this work, PRR is an ideal tool for measurements of transient droplet Evaporation/condensation processes, and can be extended to multicomponent droplets in a wide range of industrially-relevant applications.
Yingchun Wu - One of the best experts on this subject based on the ideXlab platform.
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change of Evaporation Rate of single monocomponent droplet with temperature using time resolved phase rainbow refractometry
Proceedings of the Combustion Institute, 2019Co-Authors: Yingchun Wu, Lutz Mädler, Xuecheng Wu, Gerard Grehan, Haipeng Li, Cyril CruaAbstract:Abstract Droplet Evaporation characterization, although of great significance, is still challenging. The recently developed phase rainbow refractometry (PRR) is proposed as an approach to measuring the droplet temperature, size as well as Evaporation Rate simultaneously, and is applied to a single flowing n-heptane droplet produced by a droplet-on-demand generator. The changes of droplet temperature and Evaporation Rate after a transient spark heating are reflected in the time-resolved PRR image. Results show that droplet Evaporation Rate increases with temperature, from −1.28 × 10 − 8 m2/s at atmospheric 293 K to a range of (−1.5, −8) × 10 − 8 m2/s when heated to (294, 315) K, agreeing well with the Maxwell and Stefan–Fuchs model predictions. Uncertainty analysis suggests that the main source is the indeterminate gradient inside droplet, resulting in an underestimation of droplet temperature and Evaporation Rate. With the demonstration on simultaneous measurements of droplet refractive index as well as droplet transient and local Evaporation Rate in this work, PRR is a promising tool to investigate single droplet Evaporation in real engine conditions.
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simultaneous measurement of monocomponent droplet temperature refractive index size and Evaporation Rate with phase rainbow refractometry
Journal of Quantitative Spectroscopy & Radiative Transfer, 2018Co-Authors: Yingchun Wu, Cyril Crua, Lutz Mädler, Sawitree Saengkaew, Xuecheng Wu, Haipeng Li, Gerard GrehanAbstract:Abstract The accuRate measurements of droplet temperature, size and Evaporation Rate are of great importance to characterize the heat and mass transfer during Evaporation/condensation processes. The nanoscale size change of a micron-sized droplet exactly describes its transient mass transfer, but is difficult to measure because it is smaller than the resolutions of current size measurement techniques. The Phase Rainbow Refractometry (PRR) technique is developed and applied to measure droplet temperature, size and transient size changes and thereafter Evaporation Rate simultaneously. The measurement principle of PRR is theoretically derived, and it reveals that the phase shift of the time-resolved ripple structures linearly depends on, and can directly yield, nano-scale size changes of droplets. The PRR technique is first verified through the simulation of rainbows of droplets with changing size, and results show that PRR can precisely measure droplet refractive index, absolute size, as well as size change with absolute and relative errors within several nanometers and 0.6%, respectively, and thus PRR permits accuRate measurements of transient droplet Evaporation Rates. The Evaporations of flowing single n-nonane droplet and mono-dispersed n-heptane droplet stream are investigated by two PRR systems with a high speed linear CCD and a low speed array CCD, respectively. Their transient Evaporation Rates are experimentally determined and quantitatively agree well with the theoretical values predicted by classical Maxwell and Stefan–Fuchs models. With the demonstration of Evaporation Rate measurement of monocomponent droplet in this work, PRR is an ideal tool for measurements of transient droplet Evaporation/condensation processes, and can be extended to multicomponent droplets in a wide range of industrially-relevant applications.
Juan Luis Foncubierta Blazquez - One of the best experts on this subject based on the ideXlab platform.
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experimental test for the estimation of the Evaporation Rate in indoor swimming pools validation of a new cfd based simulation methodology
Building and Environment, 2018Co-Authors: Juan Luis Foncubierta Blazquez, Ismael Rodriguez Maestre, Francisco Javier Gonzalez Gallero, Pascual Alvarez GomezAbstract:Abstract The aim of this work is to present an experimental procedure at laboratory scale that was developed to validate a new CFD-based methodology for the estimation of water Evaporation Rate in indoor swimming pools, under a wide range of convective flow conditions (36 experiments) and focussing on the most common operation conditions of these facilities: low air mean velocities (0.08–0.24 m/s), and water and air temperatures in the ranges 24-28 °C and 26-30 °C, respectively. One of the main hypotheses of the simulation methodology set a free slip wall condition (no shear stress) at the air-water interface, based on the fact that the dynamic boundary layer depth will be smaller than the thickness of the thermal and humidity boundary layers in this kind of flows. The comparison between simulated and experimental results show that the modelling stRategy proposed is a promising tool, with average relative errors of 9% for the typical mixed convection flows in indoor swimming pools.
-
a new practical cfd based methodology to calculate the Evaporation Rate in indoor swimming pools
Energy and Buildings, 2017Co-Authors: Juan Luis Foncubierta Blazquez, Ismael Rodriguez Maestre, Francisco Javier Gonzalez Gallero, Pascual Alvarez GomezAbstract:Abstract This paper presents a new methodology in which a computational fluid dynamics model is applied to estimate water Evaporation Rate in indoor swimming pools. This Rate is needed to achieve a suitable energy performance of ventilation and dehumidification systems. The main hypotheses of the model set the following boundary conditions at the air-water interface: air temperature equal to water temperature, water vapour concentration equal to saturation humidity of air at water temperature and free slip wall condition (no shear stress). This last condition can be justified by the fact that Prandtl and Schmidt turbulent numbers are usually less than one in this kind of flows. Consequently, the dynamic boundary layer depth will be smaller than the thickness of the thermal and humidity boundary layers. The model was experimentally validated by using data from three different test chambers and from a real swimming-pool. A total of 233 different flow conditions were simulated. The results were quite satisfactory, with a relative error of only 3% in the simulations of the real swimming-pool and a total average relative error smaller than 9%.