An Experimental Investigation of Enhanced Heat Transfer on Horizontal Condenser Tubes.
NAVAL POSTGRADUATE SCHOOL MONTEREY CALIF
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Heat transfer and hydrodynamic performance of three different spirally fluted tubes was determined. The tubes were 58-in. in nominal diameter and were made of aluminum. Results were compared to 58.in. OD, smooth copper-nickel and aluminum tubes. Data was taken by condensing steam at about 3 psia on the outside surface of a horizontally mounted tube in the center of a tube bank. The center tube was cooled by water on the inside at velocities of 3 to 25 feet per second. The overall heat transfer coefficient was determined directly from experimental data. The inside and outside heat transfer coefficients were determined using the Wilson plot technique. The cooling water pressure drop was measured inside the tube and converted to the friction factor in the enhanced section. The overall heat transfer coefficients of the enhanced tubes were as large as 1.75 times the corresponding smooth tube value for the same mass flow rate of cooling water. The inside heat transfer coefficients increased by about a factor of 3 while the outside heat transfer coefficients decreased by 10 to 20 percent when compared to smooth tube values. The results of this work indicate that the required condenser surface area can be reduced by 50 percent if these enhanced tubes are used in place of smooth tubes. Author
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