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RISS 인기검색어
- 검색키워드
- 저자 : Hamada Mohamed Abdelmotalib (검색결과 5 건)
- 무료
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A study on the particle temperature in a conical fluidized bed using infrared thermography
Hamada Mohamed Abdelmotalib,임익태 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.9
Of the three main modes of heat transfer in fluidized bed reactors, surface-to-bed heat transfer has been more thoroughly studied compared to gas-to-particle or solid-to-solid heat transfer. The difficulty in studying both gas-to-solid and solid-to-solid heat transfer processes is due to a limited ability to measure the temperature of the particles. The traditional method to measure temperature, such as inserting temperature probes into the bed, do not provide accurate results because these measure the temperature of the bed and not the solid particles. The present study introduces a technique using infrared thermography to measure the particle temperature. The particle temperature was measured using an IR camera, and a type-K thermocouple was used to measure the bed temperature. Glass beads with different sizes were used as bed material fluidized by air to study the effect that the inlet gas velocity and particle size had on the particle temperature. An increase in the inlet gas velocity resulted in a decrease in the particle temperature without a noticeable effect on the bed temperature, and an increase in the particle size resulted in an increase in the temperature of both the particles and the bed.
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Numerical Study on the Wall to Bed Heat Transfer in a Conical Fluidized Bed Combustor
Hamada Mohamed Abdelmotalib,Mahmoud Abdelftah Youssef,Ali Ahmed Hassan,윤석범,임익태 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.
In this work a numerical investigation of wall to bed heat transfer, and the related flow characteristics, was conducted along a conical fluidized bed combustor with a height of 0.8 m and a cone angle of 30o. A two-fluid Eulerian-Eulerian model was used while applying Kinetic Theory for Granular Flow (KTGF) to a wall-to-bed FB reactor. The heat transfer coefficient and hydrodynamics are discussed for two different drag models, namely the Gidaspow and Syamlal-O’Brien models. Furthermore, computational calculations were carried out for a variety of inlet velocities(1.4Umf~4 Umf) and different particle sizes. The heat transfer coefficient in the bed region was evaluated and compared with that calculated by penetration theory. The bed expansion for the two models was compared with that calculated using correlations from literature in order to validate the numerical calculations. The heat transfer coefficient was found to be increasing with increasing gas velocity and decreasing with increasing particle diameter.
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Mohamed Y. Hashim,Hamada M. Abdelmotalib,김종석,Dong Guk Ko,Ik-Tae Im 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.6
In this present study, the particle behavior and heat transfer coefficients for particle-gas and particle-particle are found by using a computational model in a fluidization process. A conical shape is selected as a reactor due to its wide range of applications. The equations describing gas and particle motions and heat transfer are solved by using the Eulerian two-fluid approach. Glass bead particles of two different sizes (2 mm and 4 mm) are used as bed materials, and the air is used as a fluidized gas. The velocity of the gas inlet is varied from 1.3 m/s to 2.6 m/s. The results demonstrate that the particle-gas heat transfer coefficient according to the velocity of the air inlet reaches its maximum value around 2.1 m/s, then decreases thereafter. Besides, at the same velocity, the particle-particle heat transfer coefficient reaches its maximum value, then decrease thereafter with increasing the velocity of the inlet air.
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Computational study on heat transfer and bed flow according to different regimes of fluidized beds
소병문,Hamada Mohamed Abdelmotalib,Mohamed Y. Hashim,임익태 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.12
This work presents a computational study to compare heat transfer processes and flow behavior of the bed among different regimes of fluidized bed reactors with fixed, bubbling, and slugging flow regimes. Sand particles with a mean diameter of 550 μm were used as a bed material fluidized by air. Wall-to-bed heat transfer and fluidization behavior were studied at different inlet velocities to represent different flow regimes. A two-phase model with kinetic theory of granular flow was used to simulate both heat transfer and flow characteristics. Simulation findings were validated by comparing them with available experimental results, in which there was good agreement. The obtained results demonstrated that the gas-solid heat transfer and wall-to-bed heat transfer processes strongly depend on the bed flow structure, especially void and solid volume fractions. Slugging beds related to the highest inlet velocity achieved the best conditions of a heat transfer process, as indicated by the highest gas-solid and wall-to-bed heat transfer coefficients. Simulation results also showed that slugging behavior had no negative effect on the heat transfer process despite problems such as obstruction and entrainment.
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고동국,Hamada Mohamed Abdelmotalib,Ik-Tae Im,Dong Won Im,Suck Ju Yoon 한국자동차공학회 2018 International journal of automotive technology Vol.19 No.6
In this study, in order to examine the cooling efficiency of a carbon-ceramic brake disk, the temperature distribution of the disk, depending on the AMS (Auto-Motor-Sport) Fade mode, was analyzed using a numerical method. Two brake disks with different straight ventilation hole shapes were considered. The ventilation holes configuration was changed from base models in order to find a higher cooling efficiency disk design. In the Model A disk, the mean temperatures of the mid-plane and the entire disk, at the AMS Fade mode end time decreased 1.9 oC and 3 oC, hole length respectively. This was done by decreasing the length of the a2 hole from 94 mm to 59 mm. When a2 hole length was increased from 94 mm to 128 mm, the mean temperature of the entire disk and the disk mid-plane increased 3.7 oC and 16.2 oC, respectively. This was due to the increased affined air stagnation in the disk. In the Model B disk, after removing stagnation region of the b2 hole, the hole diameter expanded from 13 mm to 17.6 mm. As a result, the mean temperature of the entre disk and the mid-plane decreased 2.8 oC and 18.7 oC, respectively, (compared to the base model). As a result, increasing the surface area of the ventilation holes gave a higher cooling efficiency.
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