F-19 Intube Fouling: Effects of Roughness and Deposit Thermal Conductivity

C. A. Bennett and L. Huang

Negative thermal fouling resistances appear frequently in the early stages of fouling. Previous studies have attributed these resistances to augmented turbulence caused by increases in surface roughness, resulting in heat transfer enhancement. This report presents a thermal and hydraulic analysis demonstrating that fouling is strongly affected by three fouling deposit properties: thickness, thermal conductivity, and surface roughness. These three factors can combine to yield thermal fouling resistances that vary from significantly positive to significantly negative. As a result, thermal fouling measurements alone do not fully describe the fouling process and must be coupled with other techniques.