Browsing by Author "Xu, Qiang"

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Citation - WoS: 9
Citation - Scopus: 11
Evaluations on Effect of Volume Fraction of Injected Air on Exergo-Economic Performance of a Shell and Tube Heat Exchanger
(Elsevier, 2022) Zhou, Xinchun; Bai, Haiping; Xu, Qiang; Mansir, Ibrahim B.; Ayed, Hamdi; Abbas, Syed Zaheer; Jarad, Fahd; Matematik
Increasing heat transfer rate in heat exchangers is one of the topics interested by researchers which leads to economic savings. Various methods have been proposed in this field which are categorized into two main groups of active and passive techniques. Despite numerous investigations were conducted in this regards, very rare investigations have probed these methods from the economic viewpoints. Present study was carried out to investigate the effect of volume fraction (VF) of air bubbles on exergo-economic performance of horizontal shell and helically coiled tube exchanger (HSHTE). The air bubbles were injected into shell side via especial method. Holes with certain properties were fabricated on a plastic pipe with diameter of 3 mm for injecting air bubbles. Both counter flow and parallel flow were considered in this investigation. Present study showed that air injection has significant effect on thermal efficiency, exergy destruction and economic performance of the HSHTE. It was found that increment of VF increases number of thermal units, first law efficiently and exergy destruction increase by 4.5, 2.4 and 12.5 times, respectably. Furthermore, best values of Net profit per unit transferred heat load (eta(p)) was about 9.3 x 10(-5) ($/J) which presented up to 13% better financial performance in comparison with parallel flow.
Citation - WoS: 7
Citation - Scopus: 8
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; Matematik
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%.