Browsing by Author "Dev, R."

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    Modeling and design validation of fluidized bed reactors for co-gasification of coal and biomass to study hydrodynamics and conversion
    (2019) Manu, J.; Dev, R.; Madav, V.
    The gasifier was designed with reaction chamber of 65mm diameter and 500 mm height. The study of gas-solid hydrodynamics is essential in designing of fluidized bed gasifier. Drag force plays a critical role in modeling fluidization behavior for gas-solid flow. This paper aims to study the effect of drag force on the fluidization parameter for the presently designed gasifier using CFD approach. The Eulerian-Eulerian model, coupled with different drag models was employed for this purpose. Time-averaged solid volume fraction, granular temperature, axial velocity of the solid particle in a lateral direction, and a central axis of the reactor were examined for different drag models like Syamlal O�Brien, Gidaspow, Mckeen and Representative unit cell. Effects of laminar and turbulent models on flow behavior were also studied. The study concluded that the McKeen model shows a relatively flat profile while estimating solid volume fraction while the RUC model overestimated the axial velocity of particles. There was relatively no change in flow behavior for the laminar and turbulent model while predicting the axial velocity of the solid particle in the lateral direction. The axial velocity of particles at a different packing factor was studied and showed no such observable difference in predicting hydrodynamics flow behavior. � 2019 ETA-Florence Renewable Energies.
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    Modeling and design validation of fluidized bed reactors for co-gasification of coal and biomass to study hydrodynamics and conversion
    (ETA-Florence Renewable Energies, 2019) Manu, J.; Dev, R.; Madav, V.
    The gasifier was designed with reaction chamber of 65mm diameter and 500 mm height. The study of gas-solid hydrodynamics is essential in designing of fluidized bed gasifier. Drag force plays a critical role in modeling fluidization behavior for gas-solid flow. This paper aims to study the effect of drag force on the fluidization parameter for the presently designed gasifier using CFD approach. The Eulerian-Eulerian model, coupled with different drag models was employed for this purpose. Time-averaged solid volume fraction, granular temperature, axial velocity of the solid particle in a lateral direction, and a central axis of the reactor were examined for different drag models like Syamlal O’Brien, Gidaspow, Mckeen and Representative unit cell. Effects of laminar and turbulent models on flow behavior were also studied. The study concluded that the McKeen model shows a relatively flat profile while estimating solid volume fraction while the RUC model overestimated the axial velocity of particles. There was relatively no change in flow behavior for the laminar and turbulent model while predicting the axial velocity of the solid particle in the lateral direction. The axial velocity of particles at a different packing factor was studied and showed no such observable difference in predicting hydrodynamics flow behavior. © 2019 ETA-Florence Renewable Energies.
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    Solar Distillation and Water Heating Systems Integration with Photovoltaic Technology
    (Springer, 2024) Dev, R.; Kashyap, Y.; Tewari, K.; Pal, P.
    Solar energy is a renewable source with three major applications: photovoltaics (PV), thermal, and daylight. A photovoltaic cell has a conversion efficiency of around 16–35%, depending upon its fabrication technology. Hence, it is observed that ~65–84% of incident solar radiation is lost as thermal energy to the surroundings. At the same time, solar thermal has vast applications, e.g., solar water heating, solar greenhouse drying, solar greenhouse crop cultivation, solar distillation, solar aquaculture, etc. Solar thermal applications have a thermal efficiency of around 20–45% depending upon fabrication materials, design, operating, and weather conditions. Integrating photovoltaic and thermal applications proved advantageous over their application with better overall efficiency. Over the years, many researchers have developed various concepts integrating these technologies to get more output, cost, and land use benefits. This chapter elaborates on different ‘PV-integrated solar distillation systems’ and ‘PV-integrated solar water heating systems’ with working principles and performances. © 2024, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.