Plate flat finned tubes heat exchanger: Heat transfer and pressure drop modeling

Abstract

Finned tubes heat exchanger is used on an innovative industrial solar dryer which consists of tree main components namely, solar concentrators, thermal room and heat exchanger. In this drying system, the heat transfer fluid coming from solar concentrators field circulates in the fin-and-tube bundles to heat the air moving through this battery to be injected into the thermal room to dry clay bricks. In this paper, we present a modeling and parametric study of the plate flat fin-and-tube bundles considering the most used models in the evaluation of the heat transfer and air flow performances. First, we carry out with a validation of the proposed physical and numerical models based on previous experimental results. In the second part we focus on the variation effects of the different geometric parameters of the tube bundles on the drying temperature and the pressure drop in order to estimate the performance evaluation criterions. Numerical results have shown that big external tube diameter increases the performance evaluation index by 67% when it varies from 20mm to 35mm which promotes the thermo-flow performances of the heat exchanger. However, Small transverse and longitudinal pitches present a higher air velocity at the minimum flow area and a stronger flow disturbance which ensure better air flow and heat transfer characteristics.