Accession Number : ADA259175


Title :   A Study of Heat Flux Induced Dryout in Capillary Grooves


Descriptive Note : Master's thesis,


Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH


Personal Author(s) : Murphy, Timothy J


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a259175.pdf


Report Date : Dec 1992


Pagination or Media Count : 246


Abstract : This is an experimental study of ethanol flowing in the narrow grooves of a copper plate which is subjected to heat fluxes sufficient to evaporate more liquid than can be replaced by capillary pumping. Three groove geometries are used: square, rectangle, and trapezoid. The objective is to simulate aspects of liquid flow in heat pipes with axial grooves. In order to validate analytical models of capillary flow in grooves, the capillary limit, dryout front location, and dryout front movement in response to power draw downs are documented. The results show the rewet performance of the groove is dependent on geometry. Grooves of higher heat transfer capacity can be poor for recovering from dryout, like the trapezoidal groove. Comparisons of the theoretical maximum heat transfer with the data are good for the square and rectangle, but overestimate the value for the trapezoid. No theory sufficiently predicted the location of the dryout front for the three geometries. For both a quiescent dryout front and a boiling dryout front, the theory does not utilize an accurate description of the geometry of the liquid front which is critical for determining the capillary pressure difference....Capillary grooves, Dryout recovery, Thin film heat, Transfer, Heat pipe, Capillary flow, Rewet.


Descriptors :   *HEAT TRANSFER , *HEAT FLUX , RECOVERY , MODELS , LIQUIDS , THERMODYNAMICS , COMPARISON , THEORY , THIN FILMS , FILMS , THESES , PIPES , PLATES , RESPONSE , COPPER , PRESSURE , GEOMETRY , POWER , ETHANOLS , BOILING , PUMPING , AXIAL FLOW , HEAT PIPES , FLOW , VALUE , TRANSFER , HEAT


Subject Categories : Fluid Mechanics
      Thermodynamics


Distribution Statement : APPROVED FOR PUBLIC RELEASE