Thermal contact resistance in plate fin-and-tube heat exchangers, determined by experimental data and CFD simulations

• New method for prediction of the mean thermal contact resistance in a fin-and-tube heat exchanger.
• Experimental and numerical methods for determination of the gas-side heat transfer coefficient.
• Experimental validation of numerical computations.
• Presented methods have a practical importance.

Plate fin-and-tube heat exchangers operate in a cross-flow arrangement. The numerical studies of performance of these heat exchangers encounter difficulties in the proper prediction of the total gas side temperature difference, because thermal contact resistance between the fin and the tube is unknown. The local measurements of its value are difficult to carry out. This paper presents a modified method for estimating the mean value of thermal contact resistance in a plate fin-and-tube heat exchanger. The proposed computational method is based on the CFD simulations and experimental measurements and it allows an accurate prediction of the total gas-side temperature difference in a heat exchanger. Furthermore, this paper presents the modified method of determining the average heat transfer coefficient for the air flow, which is similar to the technique used for experimental data reduction.