Natural convection of plate finned tube heat exchangers with two horizontal tubes in a chimney: Experimental and numerical study

This study uses a hybrid method of computational fluid dynamics (CFD) and inverse heat conduction analysis (IHCA) combined with experimental temperatures to investigate the natural convection of plate finned tube heat exchangers with two horizontal tubes located in a chimney. The influence of the position of the two heated tubes on the results obtained is considered. IHCA combined with experimental temperatures is used to estimate (h) over bar and (h(b)) over bar. Subsequently, the CFD commercial software combined with the obtained inverse results and experimental temperatures is employed to get the present results. The results reveal that the zero-equation turbulence model can be applied to determine more accurate results than the other two flow models. Therefore, the appropriate flow model for this study is the zero-equation turbulence model. The fringe pattern for each heated tube is mainly aligned in the vertical direction and the two plumes are slightly inclined toward the inward direction. The obtained velocity pattern and air temperature contour are consistent with existing interferometric images or isotherms. The proposed correlation between Ra and Nu agrees with the obtained inverse and CFD results. (C) 2019 Elsevier Ltd. All rights reserved.