Browsing by Author "Emami, Faezeh"

Now showing 1 - 2 of 2

Citation - WoS: 9
Citation - Scopus: 11
Experimental Study on Entropic Behavior of Smooth Pipe Due To the Simultaneous Usage of Spring Turbulator and Air Bubble Injection
(Elsevier, 2022) Zhou, Xinchun; Mansir, Ibrahim B.; Mahariq, Ibrahim; Ayed, Hamdi; Jarad, Fahd; Emami, Faezeh; Xu, Qiang; 02.02. Matematik; 02. Fen-Edebiyat Fakültesi; 01. Çankaya Üniversitesi
Numerous investigations were conducted to enhance heat transfer in smooth tubes. They have used both active and passive methods. However, very rare investigations have reported the simultaneous usage of active and passive methods. Furthermore, the investigations on entropic behaviors are very rare too. Through present paper, effect of air bubble injection (as active method) together with spring wire turbulator (as the passive method) is probed. The pipe was subjected to a constant heat flux. Spring pitch and fluids flow rates were variable parameters of this study. Four flow levels of 2, 3, 4, and 5 were intended for water and air. The studied parameters were Nusselt number, cost-performance coefficient, and dimensionless exergy destruction. The flow patterns were also assessed. To calculate the Nusselt number and exergy destruction, ambient temperature, pipe surface temperature, water inlet, and outlet temperatures were measured. Results showed that reducing the induced rotational flow by the pitch, affects two-phase flow and leads significant changes flow pattern and two-phase flow motion model. Air bubble injection increased Nu by 40% and dimensionless exergy destruction by 36%.
Citation - WoS: 14
Citation - Scopus: 16
Thermal, Hydraulic, Exergitic and Economic Evaluation of a Flat Tube Heat Exchanger Equipped With a Plain and Modified Conical Turbulator
(Elsevier, 2021) Ayed, Hamdi; Marzouki, Riadh; Emami, Faezeh; Mahariq, Ibrahim; Jarad, Fahd; Chen, Heng; 234808; 02.02. Matematik; 02. Fen-Edebiyat Fakültesi; 01. Çankaya Üniversitesi
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 (eta(p)). 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 eta(p). It was revealed that the application of enhanced conical turbulator would lead in the increment of eta(p) up to 1.26 times.