Heat transfer characteristics prediction in single- and multi-row heat exchangers with staggered ordering of drop-shaped tubes


Аuthors

Deeb R.

Damascus University, Syria, Damascus

e-mail: e.rawad.deeb@yandex.com, DeebR@mpei.ru

Abstract

Correlations for the average Nusselt (Nuav) number and effectiveness (ε) description of the compact heat exchanger with the drop-shaped tubes application accounting for the number of the tubes rows (NR) was obtained for the first time in the work being presented. These dropshaped tubes are disposed in the staggered ordering and placed in consecutive rows (from one to ten rows) in the direction of the flow. Each row consisted of seven tubes in the transverse direction. The Reynolds number Re ranged from 1.78×103 to 18.72×103. Convective heat transfer was being simulated with the ANSYS software. The number of tubes and Reynolds number effect on thermal characteristics of the studied heat exchangers was analyzed. Simulation results revealed that both Nuav and ε increase with the Re increasing. Moreover, the NR increase leads to ε decrease.

Maximum values of Nuav were obtained for NR = 2 and NR = 20 correspondingly. The heat exchange appeared stabilized only starting from nineteenth row. Besides, the one-row heat exchanger demonstrates better effectiveness compared to the heat exchanger with greater NR (for NR = 1, ε was about 22–27 times greater than for NR = 20). Maximum error between the numerical results and correlations obtained on their basis was ±9 %. Thus, they may be employed for the future studies and design of heat exchangers with various number of drop-shaped tubes rows.

Keywords:

drop-shaped tube, out-of-round tube, number of tube rows, Reynolds number, correlation, heat transfer, Nusselt number, effectiveness, heat exchanger, numerical study, Fluent

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