Heat transfer analysis of nine cylinders arranged inline and staggered at subcritical Reynolds number

Two-dimensional unsteady computations were performed to analyze heat transfer by two different clusters of nine circular cylinders. The cylinders were maintained at constant-heat-flux wall condition and subjected to cross-flow of air under ambient conditions. A Reynolds number of 35,000 has been considered which is in subcritical range of flow past cylinders. The experimental data pertaining to the pressure distribution has been utilized for the verification against the simulated results, resulting in a satisfactory level of agreement for the inline arrangement. The objective of the study was to examine the collective impact of longitudinal and transverse spacing on the rate of heat transfer in waste-heat-recovery recuperators (WHRRs). The study involved simulating two spacing ratios, (SL/D)/(ST/D) = 1 and 2, within a structured O-grid domain. An investigation was carried out to analyze drag, lift, and the Nusselt number while pressure distributions, vorticity, and pathline structures were utilized to understand the phenomena of heat transfer and flow. The analysis related to heat transfer data showed that the inline and staggered arrangements resulted respectively in 7 and 15.4% improvement in heat transfer ratio compared to nine single cylinders cluster operating under ideal heat transfer conditions.