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Ammar Fakhir Abdulwahid - One of the best experts on this subject based on the ideXlab platform.
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Passive Heat Transfer Enhancement review in corrugation
Experimental Thermal and Fluid Science, 2015Co-Authors: Zaid Sattar Kareem, Mohammad Nazri Mohd. Jaafar, Tholudin Mat Lazim, Shahrir Abdullah, Ammar Fakhir AbdulwahidAbstract:The Heat Transfer is a very interesting field for economical, functional and environmental reasons; it is almost related to each aspect of human lives. Therefor, the Enhancement of such field is quite essential. Passive Heat Transfer represents is the soul of Heat Transfer Enhancement due to the merits of simplicity, cheap and good Enhancement with acceptable pressure drop. Corrugation is a method involved within the passive techniques of Enhancement, it is important and being adopted in a wide range of applications like a nuclear reactor cooling, refrigeration, Heat exchangers, and other industrial applications. The current article presents an extensive review of numerical and experimental studies on Heat Transfer Enhancement, which covers the laminar and turbulent flow regions in the corrugations, especially in corrugated tubes. This paper dealt with 95.74% of papers published in corrugated tubes for different applications to offer one article representing a database stop for the designers and authors whom concerning and dealing with Heat Transfer Enhancement in corrugated tubes.
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Heat Transfer Enhancement in two-start spirally corrugated tube
Alexandria Engineering Journal, 2015Co-Authors: Zaid Sattar Kareem, Mohammad Nazri Mohd. Jaafar, Tholudin Mat Lazim, Shahrir Abdullah, Ammar Fakhir AbdulwahidAbstract:Abstract Various techniques have been tested on Heat Transfer Enhancement to upgrade the involving equipment, mainly in thermal transport devices. These techniques unveiled significant effects when utilized in Heat exchangers. One of the most essential techniques used is the passive Heat Transfer technique. Corrugations represent a passive technique. In addition, it provides effective Heat Transfer Enhancement because it combined the features of extended surfaces, turbulators and artificial roughness. Therefore, A Computational Fluid Dynamics was employed for water flowing at low Reynolds number in spiral corrugated tubes. This article aimed for the determination of the thermal performance of unique smooth corrugation profile. The Performance Evaluation Criteria were calculated for corrugated tubes, and the simulation results of both Nusselt number and friction factor were compared with those of standard plain and corrugated tubes for validation purposes. Results showed the best thermal performance range of 1.8–2.3 for the tube which has the severity of 45.455 × 10 −3 for Reynolds number range of 100–700. The Heat Transfer Enhancement range was 21.684%–60.5402% with friction factor increase of 19.2–36.4%. This indicated that this creative corrugation can improve the Heat Transfer significantly with appreciably increasing friction factor.
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Heat Transfer Enhancement in spirally corrugated tube
International Review on Modelling and Simulations (IREMOS), 2014Co-Authors: Tholudin Mat Lazim, Zaid Sattar Kareem, Mohammad Nazri Mohd. Jaafar, Shahrir Abdullah, Ammar Fakhir AbdulwahidAbstract:Passive technique have been examined on Heat Transfer Enhancement to improve the involving equipment especially in thermal transport devices. This technique exhibited significant effects when employed in Heat transport devices. Corrugations which used in many engineering applications such as Heat exchanger, chemical reactor and refrigeration systems considers as a passive technique. Corrugations provide effective Heat Transfer enlargement because it combined the features of extended surfaces, turbulators and artificial roughness. Therefore, A Computational Fluid Dynamics (CFD) simulation of fluid flow and Heat Transfer analysis of low Reynolds number in spirally corrugated tubes of horizontal orientation are presented in this paper. Constant wall Heat flux condition was applied with water as a working fluid. Reynolds number range 100-1300, a spirally corrugated tubes were examined and the results compared with standard smooth tube. Results show a Heat Transfer Enhancement range of 19.6%-71.3% with appreciable pressure drop of 19.6%-71.3%.
Chul-hwa Song - One of the best experts on this subject based on the ideXlab platform.
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Single-phase convective Heat Transfer Enhancement by spacer grids in a rod bundle
Journal of Nuclear Science and Technology, 2014Co-Authors: Sang-ki Moon, Seok Cho, Byoung-jae Kim, Jong-kuk Park, Young-jung Youn, Jongrok Kim, Chul-hwa SongAbstract:The spacer grids within a fuel assembly of a nuclear reactor core disrupt and re-establish the momentum and thermal boundary layers so that they enhance the local Heat Transfer within and downstream of the spacer grids. An experimental study in a 6×6 rod bundle has been performed to investigate the effects of spacer grids on the single-phase convective Heat Transfer Enhancement. The experimental data showed that the Reynolds number has a significant impact on the Heat Transfer Enhancement only when the Reynolds numbers are lower than about 10,000. The conventional correlations showed poor predictions of the Heat Transfer Enhancement by spacer grids at low Reynolds numbers; in particular, the maximum Heat Transfer rate at the top end of the spacer grids was significantly overestimated. Furthermore, the conventional correlations did not properly account for the effects of the Reynolds numbers on the Heat Transfer Enhancement. Therefore, more systematic experiments should be performed using various spacer gr...
Zaid Sattar Kareem - One of the best experts on this subject based on the ideXlab platform.
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Passive Heat Transfer Enhancement review in corrugation
Experimental Thermal and Fluid Science, 2015Co-Authors: Zaid Sattar Kareem, Mohammad Nazri Mohd. Jaafar, Tholudin Mat Lazim, Shahrir Abdullah, Ammar Fakhir AbdulwahidAbstract:The Heat Transfer is a very interesting field for economical, functional and environmental reasons; it is almost related to each aspect of human lives. Therefor, the Enhancement of such field is quite essential. Passive Heat Transfer represents is the soul of Heat Transfer Enhancement due to the merits of simplicity, cheap and good Enhancement with acceptable pressure drop. Corrugation is a method involved within the passive techniques of Enhancement, it is important and being adopted in a wide range of applications like a nuclear reactor cooling, refrigeration, Heat exchangers, and other industrial applications. The current article presents an extensive review of numerical and experimental studies on Heat Transfer Enhancement, which covers the laminar and turbulent flow regions in the corrugations, especially in corrugated tubes. This paper dealt with 95.74% of papers published in corrugated tubes for different applications to offer one article representing a database stop for the designers and authors whom concerning and dealing with Heat Transfer Enhancement in corrugated tubes.
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Heat Transfer Enhancement in two-start spirally corrugated tube
Alexandria Engineering Journal, 2015Co-Authors: Zaid Sattar Kareem, Mohammad Nazri Mohd. Jaafar, Tholudin Mat Lazim, Shahrir Abdullah, Ammar Fakhir AbdulwahidAbstract:Abstract Various techniques have been tested on Heat Transfer Enhancement to upgrade the involving equipment, mainly in thermal transport devices. These techniques unveiled significant effects when utilized in Heat exchangers. One of the most essential techniques used is the passive Heat Transfer technique. Corrugations represent a passive technique. In addition, it provides effective Heat Transfer Enhancement because it combined the features of extended surfaces, turbulators and artificial roughness. Therefore, A Computational Fluid Dynamics was employed for water flowing at low Reynolds number in spiral corrugated tubes. This article aimed for the determination of the thermal performance of unique smooth corrugation profile. The Performance Evaluation Criteria were calculated for corrugated tubes, and the simulation results of both Nusselt number and friction factor were compared with those of standard plain and corrugated tubes for validation purposes. Results showed the best thermal performance range of 1.8–2.3 for the tube which has the severity of 45.455 × 10 −3 for Reynolds number range of 100–700. The Heat Transfer Enhancement range was 21.684%–60.5402% with friction factor increase of 19.2–36.4%. This indicated that this creative corrugation can improve the Heat Transfer significantly with appreciably increasing friction factor.
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Heat Transfer Enhancement in spirally corrugated tube
International Review on Modelling and Simulations (IREMOS), 2014Co-Authors: Tholudin Mat Lazim, Zaid Sattar Kareem, Mohammad Nazri Mohd. Jaafar, Shahrir Abdullah, Ammar Fakhir AbdulwahidAbstract:Passive technique have been examined on Heat Transfer Enhancement to improve the involving equipment especially in thermal transport devices. This technique exhibited significant effects when employed in Heat transport devices. Corrugations which used in many engineering applications such as Heat exchanger, chemical reactor and refrigeration systems considers as a passive technique. Corrugations provide effective Heat Transfer enlargement because it combined the features of extended surfaces, turbulators and artificial roughness. Therefore, A Computational Fluid Dynamics (CFD) simulation of fluid flow and Heat Transfer analysis of low Reynolds number in spirally corrugated tubes of horizontal orientation are presented in this paper. Constant wall Heat flux condition was applied with water as a working fluid. Reynolds number range 100-1300, a spirally corrugated tubes were examined and the results compared with standard smooth tube. Results show a Heat Transfer Enhancement range of 19.6%-71.3% with appreciable pressure drop of 19.6%-71.3%.
Sang-ki Moon - One of the best experts on this subject based on the ideXlab platform.
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Single-phase convective Heat Transfer Enhancement by spacer grids in a rod bundle
Journal of Nuclear Science and Technology, 2014Co-Authors: Sang-ki Moon, Seok Cho, Byoung-jae Kim, Jong-kuk Park, Young-jung Youn, Jongrok Kim, Chul-hwa SongAbstract:The spacer grids within a fuel assembly of a nuclear reactor core disrupt and re-establish the momentum and thermal boundary layers so that they enhance the local Heat Transfer within and downstream of the spacer grids. An experimental study in a 6×6 rod bundle has been performed to investigate the effects of spacer grids on the single-phase convective Heat Transfer Enhancement. The experimental data showed that the Reynolds number has a significant impact on the Heat Transfer Enhancement only when the Reynolds numbers are lower than about 10,000. The conventional correlations showed poor predictions of the Heat Transfer Enhancement by spacer grids at low Reynolds numbers; in particular, the maximum Heat Transfer rate at the top end of the spacer grids was significantly overestimated. Furthermore, the conventional correlations did not properly account for the effects of the Reynolds numbers on the Heat Transfer Enhancement. Therefore, more systematic experiments should be performed using various spacer gr...
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Spacer grid effects on the Heat Transfer Enhancement during a reflood
2012Co-Authors: Sang-ki Moon, Seok Cho, Byoung-jae Kim, Jong-kuk Park, Young-jung YounAbstract:An experimental study using 6x6 and 2x2 square lattice rod bundles has been performed to investigate the effects of spacer grids on the Heat Transfer Enhancement during a bottom-reflood phase. The spacer grids improve a turbulent mixing of flow and induces breakup of large droplets into smaller ones. These result in the Heat Transfer Enhancement between the fuel rods and the surrounding fluid. Since the geometry of the spacer grid affects the turbulent mixing and droplet breakup behaviors, three types of spacer grids with different geometry were tested in the present study. In order to investigate the Heat Transfer Enhancement by spacer grids, single-phase steam cooling and droplet breakup by spacer grid were separately investigated. For the convective Heat Transfer Enhancement in singlephase steam flow, the Heater rod surface temperatures were measured in the vicinity of the space grid. In single-phase steam cooling experiment, the Heat Transfer was enhanced at upstream and downstream of spacer grids. Downstream of the spacer, the Heat Transfer Enhancement decays with the distance from the top end of the spacer grid exponentially. The Heat Transfer Enhancement depends on the Reynolds number as well as the flow blockage ratio. A new empirical correlation was developed in order to account for the effect of the Reynolds number. For the droplet breakup experiment, the sizes and velocities of droplets were measured across the spacer grid. The droplet breakup ratio decreases with increasing the Weber number of the droplet impacting on the spacer grid. The droplet breakup ratio by spacer grids was relatively higher than conventional correlations.
Xiaoyu Zhang - One of the best experts on this subject based on the ideXlab platform.
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physical quantity synergy analysis and efficiency evaluation criterion of Heat Transfer Enhancement
International Journal of Thermal Sciences, 2014Co-Authors: Jie Yang, Wei Liu, Xiaoyu ZhangAbstract:On the basis of the core-flow Heat Transfer Enhancement and field synergy principle, the difference between fluid-oriented and surface-oriented Heat Transfer Enhancement methods is performed. The physical nature of Heat Transfer Enhancement and friction reduction is illustrated through revealing the synergy principle of Heat Transfer and friction characteristics of physical quantity and describing the internal relations of velocity and temperature fields as well as velocity and pressure fields. The efficiency evaluation criterion (EEC) and the efficiency evaluation plot are proposed to analyze and evaluate Heat Transfer Enhancement techniques corresponding to the different regions in the efficiency evaluation plot. Region I represents the Heat Transfer Enhancement ratio is larger than the pumping power increase ratio and region II represents the Heat Transfer Enhancement ratio is less than the pumping power increase ratio in comparison with a bare tube. 3-D numerical simulations of several inserts in tube are provided to verify multi-fields synergy principle of convective Heat Transfer and efficiency evaluation plot is carried out to demonstrate the characteristics of Enhancement tubes.