Publications Scientifiques

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Author: search.filters.author.Daimallah, AhmedHas files: Yes

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    Mass flow rate enhancement inside a solar chimney power plant
    (Toronto Metropolitan University, 2023) Daimallah, Ahmed; Lebbi, Mohamed; Lounici, Mohand Said
    The Solar chimney power plant is a system that converts solar energy to mechanical energy and then to electrical energy. The present work aims to conduct numerical investigation on the influence of the radius ratio Rt* = Rtout/Rtinlet and the height of the tower-chimney, on the flow behavior inside the SCPP of Manzanares. A 2D axi-symetric turbulent model is adopted. The momentum and energy equations are solved using the finite volume method and the simple algorithm. Results show that velocity and mass flow rate inside the SCPP are affected by the radius ratio Rt*, the height of tower-chimney Ht* and intensity radiation Q. We obtain an enhancement of mass flow rate by about 58.23% for the divergence of the tower-chimney.
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    Effect of Thermal Collector Height and Radius on Hydrodynamic Flow Control in Small Solar Chimney
    (Penerbit Akademia Baru, 2020) Daimallah, Ahmed; Lebbi, Mohamed; Lounici, Mohand Said; Boutina, Lyes
    Solar chimney power plant (SCPP) is one of the promising technologies for solar energy utilization. It is an interesting system especially in large isolated desert areas due to its basic techniques and low operating costs. In this study, we investigate numerically the collector geometrical parameters effect on the hydrodynamic flow control in a solar chimney. The finite volume method and the SIMPLE algorithm have been used to solve the turbulent flow equations and energy equation. A standard K-ε model is used. The influence of the collector height (0.05m≤Hc≤0.5m) and the collector radius (2.5m≤Rc≤15m) on the flow behavior has been numerically analyzed. The obtained results indicate that increasing the collector height and collector radius affect considerablythe flow behavior and the SCPP performance. The mass flow rate is enhanced by about 27 %, for Rc=12.5m and Hc = 0.25m.
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    Numerical investigation of a novel tower solar chimney concept
    (elsevier, 2020) Kebabsa, Hakim; Lounici, Mohand Said; Daimallah, Ahmed
    Divergent tower solar chimney power plant is an attractive upgrading of the solar chimney system. However, boundary layer separation (BLS) phenomenon can appear when the divergence angle exceeds a specific value, inducing system performance degradation. The present paper proposes a novel solar chimney tower concept, named annular tower solar chimney power plant (ATSCPP), to deal with BLS phenomenon and improve the divergent tower system. Accordingly, the influence of exterior tower radius (ETR) and interior tower radius (ITR) were evaluated, using the Spanish prototype. Simulations were carried out using a 3D model. The results indicate that flow behavior, power output and thermal efficiency shows a strong sensitivity to the change of both ETR and ITR. The best case is obtained when (ETR = 17 m, ITR = 13 m). The new solar chimney tower concept allowed a significant increase in the driving potential. The total improvement in power output reaches 32%. An improved concept which allows a compromise between induced cost and performance gain of the system is also proposed.
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    Onset of instabilities in Taylor-Dean flow of yield-stress fluid
    (2009) Daimallah, Ahmed; Bouabdallah, Ahcene; Nsom, Blaise; Adnane, M.; Alemany, Antoine