Heat transfer performance of horizontal roped tubes was studied using an evaporator/condenser test rig. The condenser section contained a single horizontal tube and was operated at both vacuum and atmospheric conditions. A vacuum pump was integral to the system to ensure the presence of noncondensible gases did not affect the results. The test tubes were Wolverine MHT Korodense titanium tubes with an outside diameter of 16.07 mm and a corrugation pitch of 8 mm. The effect of wire-wrapping was studied using titanium wires ranging from 0. 1 to 1.6 mm in diameter corresponding to a range of pitch to diameter ratio from 80 to 5. The outside heat transfer coefficient, h(sub O)o, was determined by first experimentally obtaining the overall heat transfer coefficient, U(sub O)o, and then utilizing a modified Wilson Plot procedure. Results obtained for steam condensation indicate that the MHT Korodense titanium tube provides negligible enhancement compared to the a titanium tube. The addition of wire-wrapping provided minimal increase in the outside heat transfer coefficient, about 8% at a fractional coverage of approximately 5% corresponding to a pitch to wire diameter ratio near 20

Approved for public release; distribution is unlimited.

http://archive.org/details/filmwisecondensa1094527053

Lieutenant, United States Navy