Accession Number : ADA277353

Title :   Interaction Effects of a Lower Heated Tube on Pool Boiling of R-124 from an Upper Horizontal Tube.

Descriptive Note : Master's thesis,

Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s) : Yusician, Joseph E., Jr

Report Date : DEC 1993

Pagination or Media Count : 192

Abstract : An investigation of the interaction effects of a lower heated tube on pool boiling of pure R-124 from an upper horizontal tube was conducted at a saturation temperature of 2.2 deg C. The test tubes used were: (1) smooth tubes and (2) deformed surface (TURBO-B) enhanced tubes. The effects of tube spacing/configuration and lower tube heat flux on the heat transfer performance of the upper tube were investigated. For both tube arrays, the enhancing effect of bubbles from a lower tube was dramatic. This enhancement increased as lower tube heat flux increased. However, when upper tube heat fluxes were greater than 20 kW/sq. meters all enhancement disappeared. For a smooth tube array in natural convection, the effect of a lower heated tube on the heat transfer from an upper tube was small. In nucleate boiling, a P/D of 1.8 gave the best upper tube heat transfer performance and a vigorously nucleating lower tube eliminated upper tube hysteresis. With the lower tube unheated and an upper tube heat flux of greater than 3 kW/m2, the performance using R-124 was generally better than for R-114. With a nucleating lower tube (at lO kW/sq. meters), again the performance of R-124 was better, but only for upper tube heat fluxes of greater than 40 kW/sq. meters. For a TURBO-B tube array, a 30 degree offset of the upper tube reduced the upper tube heat transfer performance (compared to the in-line configurations). This may indicate bubbles depart TURBO-B tubes differently than smooth tubes.

Descriptors :   *HEAT TRANSFER, *INTERACTIONS, *NUCLEATE BOILING, *TUBES, *OZONE LAYER, ARRAYS, AUGMENTATION, BUBBLES, CONFIGURATIONS, CONVECTION, HEAT FLUX, HYSTERESIS, SATURATION, SURFACES, TEMPERATURE, TEST AND EVALUATION, THESES, DEPLETION, HALOGENATED HYDROCARBONS, REFRIGERANTS.

Subject Categories : Organic Chemistry
      Thermodynamics
      Miscellaneous Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE