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Missaoui Sami,Driss Zied,Ben Slama Romdhane,Chaouachi Bechir 대한설비공학회 2021 International Journal Of Air-Conditioning and Refr Vol.29 No.3
This study presents a coupled model to simulate the heat transfer process between the helical condenser coil and the water inside the tank. This coupled model was developed using ANSYS Fluent Computational Fluid Dynamics (CFD). The heat flux of the condenser coils is obtained from our experimental investigation and delivered as initial boundary conditions to the tank model. The results obtained are considered essential and are, in turn, capable of assessing the performance of the modified domestic refrigerator for the production of hot water. According to this model, the results confirmed that the coefficient of heat transfer and the performance of the system decreased with an increase in the heating time. The natural heat transfer coefficient Uc falls from 727.26[Formula: see text]W [Formula: see text] m[Formula: see text] [Formula: see text] K[Formula: see text] to 68.64[Formula: see text]W [Formula: see text] m[Formula: see text] [Formula: see text] K[Formula: see text] during the total heating cycle, and the water temperature rises from 20 ∘ C to 50.73∘ C. In addition, the impact of water temperature on the evaporating region was used in this analysis. Therefore, the temperature of the evaporator is unaffected by the development of hot water. As a result, these outcomes will be used for the development of the domestic refrigerator with immersed condenser coil.
Sarhan Karray,Zied Driss,Hedi Kchaou,Mohamed Salah Abid 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.7
A coupling algorithm is used to compute the equilibrium of a flexible anchor impeller in a stirred vessel. This coupling algorithm is based on a partitioned approach, which consists of three relatively independent modules: the computational fluid dynamics (CFD), the computational structure dynamics (CSD) and the interface. In the CFD module, the Euler formulation was used to account for the moving boundary. In the CSD module, the updated Lagrangian formulation for solving the motion of non-linear structure was used and a static study was adopted. In the interface module, an exchange of the forces and displacements was allowed. The numerical results, such as the velocity field, the turbulent kinetic energy, its dissipation rate, the turbulent viscosity and the mechanical deformation, have been presented. Particularly, we are interested in the study of the static behavior of the anchor impeller and the evolution of the displacement field of the arms during various iterations of our coupling algorithm. Accordingly, if the anchor impeller undergoes a deformation due to the flexion of the arms of the anchor impeller, the numerical results changes slightly from iteration to another. At the end of certain iteration,the anchor impeller becomes deformed and the velocity field is preserved. These results confirm that the fluid has a significant effect on the deformation of the arms of the anchor impeller during mixing depending on the velocity of the anchor impeller and the fluid flow. The numerical results were validated by a comparison with literature data.
Missaoui Sami,Driss Zied,Slama Romdhane Ben,Chaouachi Bechir 대한설비공학회 2022 International Journal of Air-Conditioning and Refr Vol.30 No.1
A new coupled numerical model of the overall vapor-compression cycle and water heater was developed in order to analyze the influence of condenser coil designs on the heat transfer process of a helical coil heat exchanger immersed in a storage tank. The model was developed using the CFD code ANSYS Fluent. In the numerical simulation, the helical condenser coil was treated as an internal heat source and the initial heat flux was obtained from experimental results and delivered to each coil element in the CFD model as boundary condition.The coupled model was validated with experimental results and showed that the numerical results of the proposed model are in good agreement with the experimental data with the deviation of ± 1.6%. Then, the impact of the main representative geometrical parameter on the overall heat transfer coefficient and water temperature distribution was investigated. The results indicated that the temperature distribution and overall heat transfer coefficient increase with the increase of the pipe turns of a helically coiled tube heat exchanger.
Ifa Sondes,Driss Zied 대한설비공학회 2021 International Journal of Air-Conditioning and Refr Vol.29 No.3
The human thermal comfort and the indoor healthy air quality in the houses and the offices have become a vital necessity, especially in the state of the development of the contagious virus as the COVID-19. In this study, the evaluation of the air distribution was investigated using a DHTT sensor connected to an ARDUINO card to benefit their simple use and their reasonable price comparing to other tools such as the infrared camera. The measurement of the temperature is made in 14 points divided on two directions: one near the sitting manikin and another in front with the cooling system. The impact of the heat sources was tested. In these conditions, the indoor temperature was examined for an empty room, a room occupied by one person and one computer, a room occupied by two persons and two computers and a lighted room. The experimental results prove that the indoor temperature increases with the multiplication of the heat sources. From a temperature equal to [Formula: see text]C, the PMV curves move away from the comfort zone and the indoor climate becomes hot.
Mohamed Brayek,Zied Driss,Mohamed Ali Jemni,Ali Damak,Mohamed Salah Abid 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.1
Combustion characteristics and emission in spark-ignition engines could be enhanced using hydrogen as supplementary fuel. However, its production, storage, and introduction in the combustion chamber face several challenges. To overcome the necessity of a storage device, a conventional electrolyser was used to produce a hydrogen-oxygen mixture (hydroxygen). The produced hydroxygen bubbles are characterized by their macro and nanometric size. In the present work, gasoline was on top of the water in the electrolyser. Therefore, hydroxygen nanobubbles are diffused in both water and gasoline. Combustion analysis was carried out for different engine speeds. An improvement in brake torque and a reduction in fuel consumption, HC, CO, and CO 2 emissions have been witnessed in the engine during test performance. However, the emission analysis shows a slight increase in NO x emission. Finally, this disadvantage could be neglected compared to the improvements that come with the use of hydroxygen nanobubble gasoline blends.