Abstracts Biological Sciences

A study of the effect of tube bundle geometry on the nucleate boiling region of a series of hydrocarbon liquids

by Robert Terry Montgomery

"The primary purpose of this heat transfer investigation was to determine quantitatively in what manner tube bundle geometry affects the nucleate boiling region of a tube whose single tube boiling characteristics are known. A series of tests were conducted with horizontal tube bundles which produced boiling in a saturated pool of n-hexane, n-pentane, and seven carbon (C₇) hydrocarbon mixture at atmospheric pressure. Tube bundle size and pitch were the principle independent variables considered. The phenomena of heater hysteresis and aging were also studied. Data are presented which indicates that aging probably is not a direct consequence of gas adsorption on the surface. The tube bundle data showed that the heat transfer coefficients for the individual heaters in the bundle were larger than the coefficients for the same heaters in a single tube tests particularly in the lower portion of the nucleate boiling region. this increase in the heat transfer coefficient was due to a smaller [delta]T than normal. The amount of increase in a heater's heat transfer coefficient due to boiling in a tube bundle was a function of the number of tubes in the bundle, the relative position of the heater in the bundle, the pitch of the tubes, and the fluid being boiled. Also, a semi-empirical single tubes nucleate boiling correlation which correlates the heat flux as a function of reduced temperature was derived and discussed" – Abstract, p. iv.