Experimental investigation of internally-finned tube geometries on turbulent heat-transfer and fluid flow

Abstract

Experimental investigations of variable property forced convection flow in smooth and internally-finned tubes were conducted. Length-averaged measurements of heat transfer and pressure drop for fully developed turbulent flow using water as the test fluid were obtained in fifteen pairs of finned tubes. Isothermal friction factors, diabatic friction factors, and Nusselt numbers were measured for fin geometries of 8 ≤ N ≤ 54, 0.015 ≤ H ≤ 0.017, and 0 ≤ ᵞ ≤ 45 degrees. For turbulent flow the operating conditions ranged from 7,000 < Re < 70,000, 3.5 < Pr < 5.0, and 0.62 < μb/μw < 1.35. In addition, isothermal friction factors were obtained for the range of 2,000 < Re < 12,000 using ethylene glycol as the test fluid.