Subcooling

About: Subcooling is a research topic. Over the lifetime, 6150 publications have been published within this topic receiving 99125 citations.

Condensation Measurement of Horizontal Cocurrent Steam/Water Flow

Abstract: Condensation of steam on a subcooled water layer was studied in a cocurrent horizontal channel at atmospheric pressure. The heat transfer coefficients were found to vary from 1.3 kWS/m/sup 20/C to 20 kW/m/sup 20/C, depending on whether the liquid interface was smooth or wavy, increased with increasing steam flow rates and water flow rates. For all cases, 50 to 90 percent of the steam condensed within 1.2 m from the entrance. The average Nusselt numbers were correlated with average steam and water Reynolds numbers an average liquid Prandtl numbers, for both smooth and wavy interface flows. Finally, a correlation of the average heat transfer coefficient and condensation rate for wavy interface flow was obtained as a function of inlet conditions and distance downstream.

Vapor generation in a nanoparticle liquid suspension using a focused, continuous laser

Abstract: This letter discusses experimentation with optically induced phase change in nanoparticle liquid suspensions—commonly termed nanofluids. Four different types of nanofluids at five concentrations were exposed to a ∼120 mW, 532 nm laser beam to determine the minimum laser flux needed to create vapor. Laser irradiance was varied between 0–770 W cm−2. While the experiments were simple, they involved many complex, interrelated physical phenomena, including: subcooled boiling, thermal driven particle/bubble motion, nanoparticle radiative absorption/scattering, and nanoparticle clumping. Such phenomena could enable novel solar collectors in which the working fluid directly absorbs energy and undergoes phase change in a single step.

A new CHF correlation scheme proposed for vertical rectangular channels heated from both sides in nuclear research reactors

Abstract: In this study, an investigation was carried out to identify the important parameters affecting critical heat flux (CHF) in rectangular channels, focusing on the effects of flow direction, channel inlet subcooling from 1 to 213 K, the channel outlet condition extending from subcooling of 0-74 K to quality of 0-1.0, pressure of 0.1 to 4 MPa, water mass flux of [minus]25,800 to +6250 kg/m[sup 2]s, and channel configuration. In particular, the effect of the outlet subcooling in upflow and downflow on the CHF was quantitatively investigated. As a result of this study, a new CHF scheme covering downflow, countercurrent flow, and upflow was established in the rectangular channels within the ranges of parameters investigated in this study. 17 refs., 10 figs., 1 tab.

Enhancing small-channel convective boiling performance using a microporous surface coating

Abstract: Performance characteristics are experimentally determined for enhanced convective boiling of FC-87 in a horizontal, small-cross-sectional-area, single-channel heater The channel tested has a square cross section with a side length of 2 mm and a heated length of 8 cm. The heated surface of the channel is tested both with, and without, a microporous surface coating. Although few studies have been performed to quantify the effects of internal porous coatings on flow boiling, their application in this area is promising. The coating is shown to provide increases in both heat transfer coefficient and critical heat flux. Convective boiling curves are generated for mass fluxes from 500 to 5000 kg/m 2 s and for inlet subcooling levels ranging from 2 to 31 °C.