Optimal arrangement of rotating hot cylinders in a compact heat exchanger based on energy and exergy analysis
Hamed Safikhani, Mahdi Aali, S.D. Farahani
Abstract
The chief aim of this research is to explore the various rotation patterns of hot cylinders in four non-linear structures in laminar flow regime with different rotational speed(ω). For this purpose, using the finite volume method, the thermo-hydraulic parameters such as Nusselt number (Nu), friction factor, and thermo-hydraulic performance parameter (THP) of the cooling fluid, water, were investigated. This is a three-dimensional numerical study on a compact heat exchanger in which all possible rotation patterns of hot cylinders in non-linear structures were analyzed based on energy and exergy approaches. The results showed that in each non-linear structure of the cylinders, with increasing the rotational speed, at least one of the rotation patterns had a better thermo-hydraulic performance. In this regard, 22 possible patterns are investigated in a way that one of which provides a better performance based on first and second law of thermodynamic. In the seventh rotation pattern, which is known as C27 and belongs to the second non-linear structure, the thermo- hydraulic parameter (THP) is improved by 38% compared to the linear structure of rotating hot cylinder.