CRITICAL HEAT FLUXES IN INTERNALLY HEATED ANNULI OF LARGE DIAMETER COOLED BY BOILING WATER AT 1000 PSIA

High-speed motion pictures (4300 pictures/sec) of boiling water flow patterns in conditions of forced flow at 1000 psia pressure in a vertical heated rectangular channel were taken over the range of mass velocities from 50 to 400 lb/sec-ft2, fluid states from bulk subcooled liquid flow to bulk boiling flow at 0.66 steam quality, and heat fluxes up to and including the critical heat flux level. Eighty critical heat flux determinations were made in the course of the experiment at 1000 psia in conditions of bulk boiling. The motion pictures provide photographic evidence of the general arrangement of the flow in conditions of bulk boiling at high pressure with heat fluxes near and including the critical heat flux level.

Download Full-text

Liquid Supply and Heat Transfer Performance of Sintered Cu Monolayer Wicks for Phase Change Heat Transfer Applications

ASME/JSME 2011 8th Thermal Engineering Joint Conference ◽

10.1115/ajtec2011-44356 ◽

2011 ◽

Author(s):

Stephen Sharratt ◽

Youngsuk Nam ◽

Y. Sungtaek Ju

Keyword(s):

Heat Transfer ◽

Heat Transfer Performance ◽

Large Diameter ◽

High Heat ◽

Heat Fluxes ◽

Powder Size ◽

Transfer Performance ◽

Porous Layers ◽

Different Diameters ◽

Phase Change Heat Transfer

When combined with a bi-porous or a vertical liquid artery structure, thin porous layers of high thermal conductivity materials can provide high critical heat flux while maintaining low thermal resistance. They are therefore are very promising for applications in advanced heat pipes and vapor chambers. The present study characterizes the liquid supply and heat transfer performance of monolayers of sintered Cu powders. Three sets of monolayer samples are prepared by sintering Cu powders with different diameters (29, 59, 71 um). The measured heat transfer performance is relatively insensitive to the powder diameter in the low flux regime. At relatively high heat fluxes (> 20 W/cm2) monolayers with the two large diameter powders show similar liquid supply and heat transfer performance while the sample with the smallest powder size shows significantly degraded heat transfer performance due to local dryouts.

Download Full-text

The heat loss from non-boiling water at high heat fluxes

Journal of Nuclear Energy (1954) ◽

10.1016/0891-3919(57)90043-8 ◽

1957 ◽

Vol 5 (3-4) ◽

pp. 421-423

Author(s):

V.V. Yakovlev

Keyword(s):

Heat Loss ◽

High Heat ◽

Heat Fluxes ◽

Boiling Water

Download Full-text

Development of a digital SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010008609x ◽

1991 ◽

Vol 49 ◽

pp. 358-359

Author(s):

A. Yamada ◽

A. Shibano ◽

K. Harasawa ◽

T. Kobayashi ◽

H. Fukuda ◽

...

Keyword(s):

Large Diameter ◽

Objective Lens ◽

Large Specimen ◽

Backscattered Electrons ◽

Digital Scanning ◽

Junction Type ◽

High Resolution Images ◽

Working Distance ◽

Type Detector ◽

Short Working

A newly developed digital scanning electron microscope, the JSM-6300, has the following features: Equipped with a narrower conical objective lens (OL), it allows high resolution images to be obtained easily at a short working distance (WD) and a large specimen tilt angle. In addition, it is provided with automatic functions and digital image processing functions for ease of operation.Conical C-F lens: The newly developed conical C-F objective lens, having low aberration characteristics over a wide WD range, allows a large-diameter (3-inch) specimen to be tilted up to 60° at short WD, and provides images with low magnifications starting at 10*. On the bottom of the lens, a p n junction type detector is provided to detect backscattered electrons (BE) from the specimen. As the narrower conical 0L increases the secondary electron (SE) detector's field intensity on the specimen surface, high SE image quality is obtained.

Download Full-text