The Experts below are selected from a list of 16593 Experts worldwide ranked by ideXlab platform
Frank Bruno - One of the best experts on this subject based on the ideXlab platform.
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Effective tube-in-tank PCM thermal storage for CSP applications, Part 1: Impact of tube configuration on discharging effectiveness
Solar Energy, 2016Co-Authors: Martin Belusko, Min Liu, N. H.s. Tay, Frank BrunoAbstract:Effective extraction of latent energy is critical in phase change material (PCM) thermal storage applications, including CSP plants. For tube-in-tank arrangements, research to date has not explicitly investigated the impact of the boundary condition applied to the PCM surrounding the tube on the heat transfer process. In Part 1 of this study, the impact of this boundary condition was investigated by applying different tube configurations, defined by the heat transfer fluid either flowing parallel, Counterflow or in a serpentine arrangement. The study identified that the critical factor was the loss of heat transfer area experienced once the phase front between parallel tubes meet. This was significant for parallel flow but essentially eliminated for the Counterflow arrangement, which delivered a more uniform phase front parallel to the tube wall. As a result it was identified that the amount of redundant PCM when applying the Counterflow arrangement was 9%, while this value was 32% for the parallel flow arrangement. This difference has a significant impact on the cost of thermal storage for CSP plants. Part 2 will involve a parametric assessment of the parallel and Counterflow configurations.
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Effective tube-in-tank PCM thermal storage for CSP applications, Part 2: Parametric assessment and impact of latent fraction
Solar Energy, 2016Co-Authors: Martin Belusko, Min Liu, N. H.s. Tay, Frank BrunoAbstract:The tube-in-tank is a compact configuration well suited for PCM thermal storage systems. However limited research has investigated the impact of the boundary condition applied to the PCM achieved through differing tube arrangements. In Part 1, using CFD and considering the discharging condition for CSP applications, it was determined that when the heat transfer fluid flow was in parallel, poor extraction of latent energy occurs, whereas in a Counterflow arrangement maximum latent energy is extracted. In Part 2, the impact of mass flow rate and PCM thermal conductivity on the extraction of latent energy for these tube arrangements was investigated. It was discovered that the Counterflow arrangement can experience poorer heat transfer which can be avoided through design. Furthermore, little investigation has considered the impact of the effectiveness of heat transfer with PCM systems with increased amounts of sensible energy, typical for CSP applications. It was determined that for latent dominant storage systems, the Counterflow tube arrangement should be applied, while for sensible dominant PCM storage systems, parallel flow should be considered.
Martin Belusko - One of the best experts on this subject based on the ideXlab platform.
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Effective tube-in-tank PCM thermal storage for CSP applications, Part 1: Impact of tube configuration on discharging effectiveness
Solar Energy, 2016Co-Authors: Martin Belusko, Min Liu, N. H.s. Tay, Frank BrunoAbstract:Effective extraction of latent energy is critical in phase change material (PCM) thermal storage applications, including CSP plants. For tube-in-tank arrangements, research to date has not explicitly investigated the impact of the boundary condition applied to the PCM surrounding the tube on the heat transfer process. In Part 1 of this study, the impact of this boundary condition was investigated by applying different tube configurations, defined by the heat transfer fluid either flowing parallel, Counterflow or in a serpentine arrangement. The study identified that the critical factor was the loss of heat transfer area experienced once the phase front between parallel tubes meet. This was significant for parallel flow but essentially eliminated for the Counterflow arrangement, which delivered a more uniform phase front parallel to the tube wall. As a result it was identified that the amount of redundant PCM when applying the Counterflow arrangement was 9%, while this value was 32% for the parallel flow arrangement. This difference has a significant impact on the cost of thermal storage for CSP plants. Part 2 will involve a parametric assessment of the parallel and Counterflow configurations.
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Effective tube-in-tank PCM thermal storage for CSP applications, Part 2: Parametric assessment and impact of latent fraction
Solar Energy, 2016Co-Authors: Martin Belusko, Min Liu, N. H.s. Tay, Frank BrunoAbstract:The tube-in-tank is a compact configuration well suited for PCM thermal storage systems. However limited research has investigated the impact of the boundary condition applied to the PCM achieved through differing tube arrangements. In Part 1, using CFD and considering the discharging condition for CSP applications, it was determined that when the heat transfer fluid flow was in parallel, poor extraction of latent energy occurs, whereas in a Counterflow arrangement maximum latent energy is extracted. In Part 2, the impact of mass flow rate and PCM thermal conductivity on the extraction of latent energy for these tube arrangements was investigated. It was discovered that the Counterflow arrangement can experience poorer heat transfer which can be avoided through design. Furthermore, little investigation has considered the impact of the effectiveness of heat transfer with PCM systems with increased amounts of sensible energy, typical for CSP applications. It was determined that for latent dominant storage systems, the Counterflow tube arrangement should be applied, while for sensible dominant PCM storage systems, parallel flow should be considered.
Kaoru Maruta - One of the best experts on this subject based on the ideXlab platform.
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extinction characteristics of ch4 o2 xe radiative Counterflow planar premixed flames and their transition to ball like flames
Combustion and Flame, 2013Co-Authors: Koichi Takase, Xing Li, Hisashi Nakamura, Takuya Tezuka, Susumu Hasegawa, Masato Katsuta, Masao Kikuchi, Kaoru MarutaAbstract:Abstract Extinction characteristics of CH4/O2/Xe radiative Counterflow premixed flames and their transition to ball-like flames were examined by computations and microgravity experiments. First, the flammability limit of flame ball for the mixture was estimated to be leaner than that of Counterflow premixed flame by one-dimensional computations with detailed chemistry. Extinction experiments under microgravity showed that there was a ball-like flame prior to total extinction in the vicinity of the stagnation-plane in the low-speed Counterflow field at stretch rate of 1.6–3.2 s−1. Formation of such a ball-like flame occurred subsequent to the extinction of Counterflow flames and the ball-like flame was finally extinguished when the equivalence ratio was further decreased. Two-dimensional computations indicated that the temperature of the ball-like flame increased with the decrease of equivalence ratio in the near-limit condition when it approached extinction. The temperature distribution of the computational ball-like flame was in qualitative agreement with that of the flame ball. The ball-like flame in the Counterflow field was considered to be stable based on steady-state two-dimensional computation at an equivalence ratio slightly richer than the limit of a transient ball-like flame. Such a stable computational ball-like flame is not perfectly spherical. The ball-like flame observed in this study is thought to have a close correlation with the ideal flame ball which is generally established in a quiescent mixture.
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effects of the lewis number and radiative heat loss on the bifurcation and extinction of ch4 o2 n2 he flames
Journal of Fluid Mechanics, 1999Co-Authors: Yiguang Ju, Kaoru MarutaAbstract:Eects of the Lewis number and radiative heat loss on flame bifurcations and extinc- tion of CH 4/O2-N2-He flames are investigated numerically with detailed chemistry. Attention is paid to the interaction between radiation heat loss and the Lewis number eect. The Planck mean absorption coecients of CO, CO2, and H2O are calculated using the statistical narrow-band model and compared with the data given by Tien. The use of Tien's Planck mean absorption coecients overpredicts radiative heat loss by nearly 30 % in a Counterflow conguration. The new Planck mean absorption coecients are then used to calculate the extinction limits of the planar propagating flame and the Counterflow flame when the Lewis number changes from 0.967 to 1.8. The interaction between radiation heat loss and the Lewis number eect greatly enriches the phenomenon of flame bifurcation. The existence of multiple flames is shown to be a physically intrinsic phenomenon of radiating Counterflow flames. Eight kinds of typical patterns of flame bifurcation are identied. The competition between radiation heat loss and the Lewis number eect results in two distinct phenomena, depending on if the Lewis number is greater or less than a critical value. Comparisons between the standard limits of the unstrained flames and the flammability limits of the Counterflow flames indicate that the flammability limit of the Counterflow flame is lower than the standard limit when the Lewis number is less than the critical value and is equal to the standard limit when the Lewis number is higher than this critical value. Finally, a G-shaped curve and a K-shaped curve which respectively represent the flammable regions of the multiple flames for Lewis numbers lower and higher than the critical value are obtained. The G- and K-shaped curves show a clear relationship between the stretched Counterflow flame and the unstrained planar flame. The present results provide a good explanation of the physics revealed experimentally in microgravity.
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Effects of the Lewis number and radiative heat loss on the bifurcation and extinction of CH4/O2-N2-He flames
Journal of Fluid Mechanics, 1999Co-Authors: Yiguang Ju, Kaoru MarutaAbstract:Eects of the Lewis number and radiative heat loss on flame bifurcations and extinc- tion of CH 4/O2-N2-He flames are investigated numerically with detailed chemistry. Attention is paid to the interaction between radiation heat loss and the Lewis number eect. The Planck mean absorption coecients of CO, CO2, and H2O are calculated using the statistical narrow-band model and compared with the data given by Tien. The use of Tien's Planck mean absorption coecients overpredicts radiative heat loss by nearly 30 % in a Counterflow conguration. The new Planck mean absorption coecients are then used to calculate the extinction limits of the planar propagating flame and the Counterflow flame when the Lewis number changes from 0.967 to 1.8. The interaction between radiation heat loss and the Lewis number eect greatly enriches the phenomenon of flame bifurcation. The existence of multiple flames is shown to be a physically intrinsic phenomenon of radiating Counterflow flames. Eight kinds of typical patterns of flame bifurcation are identied. The competition between radiation heat loss and the Lewis number eect results in two distinct phenomena, depending on if the Lewis number is greater or less than a critical value. Comparisons between the standard limits of the unstrained flames and the flammability limits of the Counterflow flames indicate that the flammability limit of the Counterflow flame is lower than the standard limit when the Lewis number is less than the critical value and is equal to the standard limit when the Lewis number is higher than this critical value. Finally, a G-shaped curve and a K-shaped curve which respectively represent the flammable regions of the multiple flames for Lewis numbers lower and higher than the critical value are obtained. The G- and K-shaped curves show a clear relationship between the stretched Counterflow flame and the unstrained planar flame. The present results provide a good explanation of the physics revealed experimentally in microgravity.
Min Liu - One of the best experts on this subject based on the ideXlab platform.
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Effective tube-in-tank PCM thermal storage for CSP applications, Part 1: Impact of tube configuration on discharging effectiveness
Solar Energy, 2016Co-Authors: Martin Belusko, Min Liu, N. H.s. Tay, Frank BrunoAbstract:Effective extraction of latent energy is critical in phase change material (PCM) thermal storage applications, including CSP plants. For tube-in-tank arrangements, research to date has not explicitly investigated the impact of the boundary condition applied to the PCM surrounding the tube on the heat transfer process. In Part 1 of this study, the impact of this boundary condition was investigated by applying different tube configurations, defined by the heat transfer fluid either flowing parallel, Counterflow or in a serpentine arrangement. The study identified that the critical factor was the loss of heat transfer area experienced once the phase front between parallel tubes meet. This was significant for parallel flow but essentially eliminated for the Counterflow arrangement, which delivered a more uniform phase front parallel to the tube wall. As a result it was identified that the amount of redundant PCM when applying the Counterflow arrangement was 9%, while this value was 32% for the parallel flow arrangement. This difference has a significant impact on the cost of thermal storage for CSP plants. Part 2 will involve a parametric assessment of the parallel and Counterflow configurations.
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Effective tube-in-tank PCM thermal storage for CSP applications, Part 2: Parametric assessment and impact of latent fraction
Solar Energy, 2016Co-Authors: Martin Belusko, Min Liu, N. H.s. Tay, Frank BrunoAbstract:The tube-in-tank is a compact configuration well suited for PCM thermal storage systems. However limited research has investigated the impact of the boundary condition applied to the PCM achieved through differing tube arrangements. In Part 1, using CFD and considering the discharging condition for CSP applications, it was determined that when the heat transfer fluid flow was in parallel, poor extraction of latent energy occurs, whereas in a Counterflow arrangement maximum latent energy is extracted. In Part 2, the impact of mass flow rate and PCM thermal conductivity on the extraction of latent energy for these tube arrangements was investigated. It was discovered that the Counterflow arrangement can experience poorer heat transfer which can be avoided through design. Furthermore, little investigation has considered the impact of the effectiveness of heat transfer with PCM systems with increased amounts of sensible energy, typical for CSP applications. It was determined that for latent dominant storage systems, the Counterflow tube arrangement should be applied, while for sensible dominant PCM storage systems, parallel flow should be considered.
N. H.s. Tay - One of the best experts on this subject based on the ideXlab platform.
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Effective tube-in-tank PCM thermal storage for CSP applications, Part 1: Impact of tube configuration on discharging effectiveness
Solar Energy, 2016Co-Authors: Martin Belusko, Min Liu, N. H.s. Tay, Frank BrunoAbstract:Effective extraction of latent energy is critical in phase change material (PCM) thermal storage applications, including CSP plants. For tube-in-tank arrangements, research to date has not explicitly investigated the impact of the boundary condition applied to the PCM surrounding the tube on the heat transfer process. In Part 1 of this study, the impact of this boundary condition was investigated by applying different tube configurations, defined by the heat transfer fluid either flowing parallel, Counterflow or in a serpentine arrangement. The study identified that the critical factor was the loss of heat transfer area experienced once the phase front between parallel tubes meet. This was significant for parallel flow but essentially eliminated for the Counterflow arrangement, which delivered a more uniform phase front parallel to the tube wall. As a result it was identified that the amount of redundant PCM when applying the Counterflow arrangement was 9%, while this value was 32% for the parallel flow arrangement. This difference has a significant impact on the cost of thermal storage for CSP plants. Part 2 will involve a parametric assessment of the parallel and Counterflow configurations.
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Effective tube-in-tank PCM thermal storage for CSP applications, Part 2: Parametric assessment and impact of latent fraction
Solar Energy, 2016Co-Authors: Martin Belusko, Min Liu, N. H.s. Tay, Frank BrunoAbstract:The tube-in-tank is a compact configuration well suited for PCM thermal storage systems. However limited research has investigated the impact of the boundary condition applied to the PCM achieved through differing tube arrangements. In Part 1, using CFD and considering the discharging condition for CSP applications, it was determined that when the heat transfer fluid flow was in parallel, poor extraction of latent energy occurs, whereas in a Counterflow arrangement maximum latent energy is extracted. In Part 2, the impact of mass flow rate and PCM thermal conductivity on the extraction of latent energy for these tube arrangements was investigated. It was discovered that the Counterflow arrangement can experience poorer heat transfer which can be avoided through design. Furthermore, little investigation has considered the impact of the effectiveness of heat transfer with PCM systems with increased amounts of sensible energy, typical for CSP applications. It was determined that for latent dominant storage systems, the Counterflow tube arrangement should be applied, while for sensible dominant PCM storage systems, parallel flow should be considered.
