Effects of the Fouling on the Convective Heat Transfer Field Synergy in Round Tube

Abstract

Numerical simulated for the tube of different scale thickness, and analysis the fouling effect for the velocity and temperature fields and their synergism number and synergism angle. The numerical simulation results show that, in the laminar flow and turbulent flow condition, the average field synergism number increases with the increases of fouling thickness, but decreases with the increases of Reynolds number, while average synergy angle is opposite. The synergy number is greater in turbulent flow than in laminar flow, while synergy angle is less in turbulent flow. The local synergy numbers decrease gradually in the axial direction when the flow is turbulent flow. For the synergy number, the decreased velocity is fastest in entrance region and the change of velocity becomes flat after fully developed flow. In entrance region the local synergy angle increases gradually in the axial direction. The flow starts to become fully-develop turbulent flow in 0.04m, and local synergy angle reaches a certain value gradually. The results can be used to enhance heat transfer and improve the heat transfer coefficient more effectively.