Investigation of a mixed-convective heat treatment of single-air air cooled exchangers in various cross-steps pipe installation
The article presents a study of single-row air-cooled heat exchangers consisting of bimetallic rolling aluminum finned tubes with different transverse steps of their installation, equipped with an additional intensifying device - a suction shaft, of various heights. The methodology of processing the obtained experimental data is analyzed and the Nusselt numbers reliance on Grashof numbers are presented. The physical picture of the air flow structure passing through a single-row horizontal finned beam is analyzed. Because of the analysis, it was concluded that the installation of the exhaust shaft above the beam leads to a significant increase in heat transfer by a factor of 2.5-3.0, but the efficiency of heat transfer depends on the height of the extraction shaft and on the back spacing. In such case the mixed convective heat transfer reliance on back spacing is differed from a character of dependence as compared to free convection heat exchange.