Aerodynamic resistance of heat exchangers

Aerodynamic resistance affects the performance of plate fin-and-tube heat exchangers. As air speed increases, the pressure drops and energy consumption for its movement increases. Both indicators depend in a complex way on the combination of design and operating parameters of heat exchangers. Experimental data on the aerodynamic resistance of heat exchangers with different geometric parameters have been collected from available sources. 21 correlations were used to calculate the Fanning factor or pressure drop. Calculations of the pressure drop were performed by each correlation over the entire range of geometric and operating parameters, which are indicated in the sources describing the experimental data. Calculations were carried out using a program compiled in MS Excel. Current ΔPi and average ΔPс pressure drop values were compared with experimental data ΔPэ.i and ΔPэ.с. Only two correlations provide satisfactory agreement between calculation results and experimental data in a wide range of geometric parameters. A multiple linear regression analysis of experimental data was performed for all of them and separately for heat exchangers with staggered and in-line tube arrangements. For each of them, the agreement between the calculation results and experimental data is better than for the selected correlations. On the graphs of the ratio ΔPi/ΔPэ.i outlier points are found, which indicates the inconsistency of the experimental data obtained by different researchers. More experimental data is required for more accurate pressure drop calculations, especially for heat exchangers with fin pitch greater than 4 mm.