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ISSN Online: 2377-424X

International Heat Transfer Conference 5
September, 3-7, 1974, Tokyo, Japan

A COMPARATIVE STUDY OF VERTICAL UPFLOW AND DOWNFLOW IN A UNIFORMLY HEATED BOILING FLUID

Get access (open in a dialog) DOI: 10.1615/IHTC5.390
pages 155-159

摘要

A comparative experimental study of the hydrodynamics and heat transfer behavior of single-phase and boiling Freon-113 in vertical upflow and downflow is presented. The study was performed using electrically heated, 1.24 cm diameter Inconel tubes with a length to. diameter ratio of 150. Mass velocities ranged up to 2.7 × 103 kg/m2-sec, and heat fluxes up to 12.6 × 104 W/m2 were obtained. The inlet pressure was varied from 2.41 × 105 to 7.93 × 105 N/m2 (2.41-7.93 bar) and the inlet subcooling from 17°C to approximately saturation temperature. Heat fluxes were adjusted to provide a range of exit qualities from zero to 30%. Flow visualization at the test section exits revealed significantly different flow patterns for upflow and downflow during boiling. This difference was manifested by disparities in the pressure drop and heat transfer behaviors, as attested to by results presented.