Browsing by Author "Ayed, Hamdi"

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Citation Count: Fan, Guangli...et al. (2021). "Energy and exergy and economic (3E) analysis of a two-stage organic Rankine cycle for single flash geothermal power plant exhaust exergy recovery", Case Studies in Thermal Engineering, Vol. 28.
Energy and exergy and economic (3E) analysis of a two-stage organic Rankine cycle for single flash geothermal power plant exhaust exergy recovery
(2021) Fan, Guangli; Gao, Yingjie; Ayed, Hamdi; Marzouki, Riadh; Aryanfar, Yashar; Jarad, Fahd; Guo, Peixi; 234808
A two-stage ORC (Organic Rankine Cycle) is being proposed for the recovery and utilization of low-grade heat from single flash geothermal power plant exhaust flue fluids. The working fluids for two-stage the recovery system are R227ea and R116. The impact of essential design parameters such as inlet temperature of the cycle, ambient temperature, geothermal turbine inlet pressure, geothermal condensation temperature on system performance are investigated using thermodynamic mathematical models regarding energy and exergy efficiencies as the objective function. The addition of the recovery section to the base cycle improves the thermal efficiency from 0.2023 to 0.2178, a 7.66% improvement in this critical metric. Furthermore, the exergy efficiency rises from 0.55044 to 0.5803, representing a 15.04% boost in exergy efficiency. Furthermore, the system's overall output rises from 7690 kW to 9898 kW, representing a substantial gain of 28.71%. The suggested recovery system's cycle has a lower LEC than a single flash geothermal cycle from an economic standpoint. LEC Reduced from $ 0.125 per kilowatt to $ 0.108 per kw, a cost savings. As a result, including a recovery section in the basic single flash geothermal cycle will significantly improve system performance.
Citation Count: Ayed, Hamdi;...et.al. (2022). "Experimental investigation on the thermo-hydraulic performance of air–water two-phase flow inside a horizontal circumferentially corrugated tube", Alexandria Engineering Journal, Vol.61, No.9, pp.6769-6783.
Experimental investigation on the thermo-hydraulic performance of air–water two-phase flow inside a horizontal circumferentially corrugated tube
(2022) Ayed, Hamdi; Arsalanloo, Akbar; Khorasani, Saleh; Youshanlouei, Mohammad Mehdizadeh; Jafarmadar, Samad; Abbasalizadeh, Majid; Jarad, Fahd; Mahariq, Ibrahim; 234808
In this study, flow visualization, pressure drop and thermal characteristics of the corrugated tube with non-boiling air–water two-phase flow were experimentally studied. Glass tubes were used to visualize the flow patterns of two-phase flow. Furthermore, the thermal behavior of two phase flow was studied in the copper made tubes which was under constant heat flux. The total of 740 W thermal energy was applied on tubes. Superficial velocity of liquid was within the range of 0.42 m/s to 1.69 m/s. Also, the superficial velocity of air was within the range of 0.21 m/s to 1.06 m/s. The results revealed that the corrugations significantly affect the flow patterns which results in earlier transition. The flow patterns of bubbly, churn, wavy slug, wavy plug, wavy stratified and mist flow were observed inside corrugated tube. Also, it was found that the maximum Nusselt number increment in corrugated tube was 3%. Besides, formation of the mist flow in corrugated tube reduced the Nusselt number. Also, the pressure drop was significantly affected by the air–water two-phase flow presenting around 165 % in the pressure drop compared to the single phase flow.
Citation Count: Cao, Yan;...et.al. (2022). "Heat transfer improvement between a pair of heater and cooler inside an energy storage by using nano-encapsulated phase change material/water: A numerical modeling", Case Studies in Thermal Engineering, Vol.30.
Heat transfer improvement between a pair of heater and cooler inside an energy storage by using nano-encapsulated phase change material/water: A numerical modeling
(2022) Cao, Yan; Farouk, Naeim; Ayed, Hamdi; Aly, Ayman A.; Jarad, Fahd; Dahari, Mahidzal; Wae-hayee, Makatar; Saleh, B.; 234808
In the present study, the natural convection flow of water with Nano-encapsulated phase change material (NPCM) was simulated inside an insulated chamber, which a pair of pipes were considered as a heater and cooler sources with the boundary condition of uniform temperature. The NPCM's core was made of n-nonadecane with melting temperature of 30.44°C. This core has ability to change the liquid-solid phase to transfer heat between the heater and the cooler sources. Current simulation was steady state and was solved by SIMPLE algorithm based on FVM to investigate the effects of Rayleigh number, volume fraction and location of phase change zone on the convective heat transfer coefficient. Observations showed that, phase change of NPCM occurs at low Rayleigh numbers but had no effect on the convective heat transfer coefficient, but it was directly related to the thermal conductivity of mixture. Moreover, adding volume fraction of NPCM 0.02 into water increased the convective heat transfer coefficient by 10.43%, 19.1% and 18.3% compared to pure water for Rayleigh numbers 102,104,and106, respectively.
Citation Count: Cao, Yan...et al. (2021). "Inducing swirl flow inside the pipes of flat-plate solar collector by using multiple nozzles for enhancing thermal performance", Renewable Energy, Vol. 180, pp. 1344-1357.
Inducing swirl flow inside the pipes of flat-plate solar collector by using multiple nozzles for enhancing thermal performance
(2021) Cao, Yan; Ayed, Hamdi; Hashemian, Mehran; Issakhov, Alibek; Jarad, Fahd; Wae-hayee, Makatar; 234808
In this numerical study, an attempt has been made to improve the thermal performance of the flat-plate solar collector (FPSC) by inducing the swirl flow inside the tube by the considered nozzles. To this end, the effect of the number of circumferential nozzles and their inclination angles was taken into the account. The considered number of nozzles was "single", ''dual'', ''triple'', and ''quad''. For each of the said cases, the inclination angle of nozzles was taken 30°, 45°, 60°, and 90° (A30, A45, A60, A90). Moreover, the mass flow rate of single-nozzle pipe was considered 0.2 kg/s, 1 kg/s, and 2 kg/s. To analyze all of the cases under identical conditions, the said mass flow rates were distributed equally among all of the nozzles (for ''dual'', ''triple'', and ''quad''). All of the characteristics were defined in a form of "A…-D…-N…-M…'' where ''A…'', "D…", "N…", and “M…” stand for angle of injection, diameter of pipe, nozzle cross-section edge, and mass flow rate, respectively. Numerical simulation (3-dimensional) of the system was performed by Finite Volume Method (FVM). The turbulence nature of flow was simulated by the k-omega SST (shear stress transport) turbulent model. Results showed that the "single-nozzle'' swirl generator had the highest thermal performance factor (TPF) so that for all cases its values were greater than unit. Mass flow rate growth increases Nu, heat extraction rate, and kinetic energy rate (KER) while drops friction factor and outlet temperature. Increment of injection angle increases outlet temperature and friction factor and reduces KER. The maximum and minimum values of TPF are 4.19 and 0.44 which belong to “single; A30-D50-N12.5-M0.2” and "quad; A90-D50-N12.5-M0.5", respectively. © 2021 Elsevier Ltd
Citation Count: Cao, Yan...et al. (2021). "MHD natural convection nanofluid flow in a heat exchanger: Effects of Brownian motion and thermophoresis for nanoparticles distribution", Case Studies in Thermal Engineerin, Vol. 28.
MHD natural convection nanofluid flow in a heat exchanger: Effects of Brownian motion and thermophoresis for nanoparticles distribution
(2021) Cao, Yan; Ayed, Hamdi; Jarad, Fahd; Togun, Hussein; Alias, Hajar; Issakhov, Alibek; Dahari, Mahidzal; Wae-hayee, Makatar; El Ouni, M.H.; 234808
The free convection of Cu-water nanofluid is simulated and investigated inside a square heat exchanger chamber in the presence of MHD magnetic field. The Buongiorno model with the effects of Brownian and thermophoresis motion is considered to nanoparticles distribution inside the chamber. The geometry consists of a square chamber with two cylinders on the right and left sides as heater and cooler in order to create the buoyancy force, respectively. These cylinders represent hot and cold pipes, and the walls of the chamber are heat and mass insulation. the FVM with SIMPLE algorithm are used for velocity and pressure coupling. In current two-phase simulation, the effects of Rayleigh number, Hartmann number, inclination angle of chamber and volume fraction on streamline contours, isothermal lines, Lorentz force lines, nanoparticle distribution and Nusselt number are investigated. By modeling the motion of nanoparticles and evaluating it, a nanoparticle transport zone was observed. The diffusion effects of thermophoresis were significant in this zone. The nanoparticles were thrown from the hot cylinder to the cold cylinder. The application of a magnetic field enlarged the nanoparticle transport zone. However, increasing the Rayleigh number and decreasing the inclination angle of the enclosure caused the nanoparticles to disperse evenly. © 2021 The Authors
Citation Count: Ayed, Hamdi...et all. (2021). "Thermal, efficiency and power output evaluation of pyramid, hexagonal and conical forms as solar panel", Case Studies in Thermal Engineering, Vol. 27.
Thermal, efficiency and power output evaluation of pyramid, hexagonal and conical forms as solar panel
(2021) Ayed, Hamdi; Moria, Hazim; Aldawi, Fayez; Farouk, Naeim; Sharma, Kamal; Youshanlouei, Mohammad Mehdizadeh; Mahariq, Ibrahim; Jarad, Fahd; 234808
Through the present investigation, the thermal and power output of novel-shaped solar panels are evaluated. For the cooling of the mentioned forms, forced air flow was utilized. Three novel shapes, of Pyramid, Hexagonal, and Conical which had the equal lateral surface were considered. For the simulation, an open source CFD software was utilized. The lateral surfaces were put under identical amount of heat flux. Air as the coolant fluid was injected with constant inlet temperature from the trapdoors at the bottom of different shaped structures. Three different values of heat flux and air injection rate were evaluated for each shape. The outcomes presented that the conical shaped solar panel exhibits better thermal performance than other geometries. Furthermore, conical form finds the least temperature that was about 10.5 °C less than that of the pyramid-shaped panel. Furthermore, it was revealed that the corners of pyramid and hexagonal-shaped solar panels have higher temperature. Also, it was found that the efficiency of conical shaped panel was up to 8.4% more than that of pyramid-shaped panel.
Citation Count: Chen, Heng...et al. (2021). "Thermal, hydraulic, exergitic and economic evaluation of a flat tube heat exchanger equipped with a plain and modified conical turbulator", Case Studies in Thermal Engineering, Vol. 28.
Thermal, hydraulic, exergitic and economic evaluation of a flat tube heat exchanger equipped with a plain and modified conical turbulator
(2021) Chen, Heng; Ayed, Hamdi; Marzouki, Riadh; Emami, Faezeh; Mahariq, Ibrahim; Jarad, Fahd; 234808
Increasing use of fossil fuels has led to serious consequences on the environment including global warming, pollution, and increased costs of heating systems. This indicates the importance of improving the efficiency of devices used in heating and air conditioning systems such as heat exchangers. In this study, it was tried to enhance the performance of the heat exchanger by simultaneous use of a flat tube as a central tube of the heat exchanger and dual conic turbulator. In addition to plain conical turbulator, the influence of the conical turbulator with aerodynamic geometry was investigated on the heat transfer and pressure drop. Finally, economic evaluation of the studied cases was done based on the thermal performance enhancement factor (TEF) and the net profit of unit transferred heat load (ηp). Tests were conducted in the hot water flow rate ranging 0.033–0.0678 L/s while cold water flow rate was kept constant at 0.166 L/s. The results indicated that the heat transfers and exergy loss of the flat tube heat exchanger with a dual modified conical turbulator was up to 33% and 30% higher than the plain tube heat exchanger, respectively. Also, a heat exchanger with a modified dual turbulator with convergent embellishment (case B) selected as the economic case and has the highest TEF and ηp. It was revealed that the application of enhanced conical turbulator would lead in the increment of ηp up to 1.26 times.