The effect of longitudinal spacer ribs on the minimum pressure drop in a heated annulus

Conference · Mon Jan 01 04:00:00 EST 1990

OSTI ID:6452866

Johnston, B S; Neff, J M

When evaluating a heated flow passage for vulnerability to static flow excursions, special note should be taken of flow restrictions which might allow premature vapor generation. In this study, measurements of steady state pressure drop were made for the downward flow of water in a vertical annulus. The outer wall was uniformly heated to allow subcooled boiling. Minima in the pressure drop characteristics were compared for test sections with and without longitudinal spacer ribs. For a given power and inlet temperature, the minimum occurred at a higher flow rate in the ribbed test section. This is attributed to vapor generation at the ribs. The work cited in this document show how a restriction in a heated channel can produce vapor which would not be observed in the absence of the restriction. In the present study, the effect of a flow restriction on the tendency to flow excursion is explored by finding demand curves for a heated annulus in subcooled boiling flow. The annulus is heated from the outside, and alternately equipped with and without longitudinal spacer ribs. These ribs separate the heated and unheated walls; in pressing against the heated wall they provide a means for premature vapor production.

• Research Organization: Westinghouse Savannah River Co., Aiken, SC (USA)
• Sponsoring Organization: DOE/DP
• DOE Contract Number: AC09-89SR18035
• OSTI ID: 6452866
• Report Number(s): WSRC-MS-90-158; CONF-901194--4; ON: DE91000784
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420400* -- Engineering-- Heat Transfer & Fluid Flow
ANNULAR SPACE
BOILING
CONFIGURATION
ENERGY TRANSFER
FLOW MODELS
FLOW RATE
FLUID FLOW
FLUID MECHANICS
FLUIDS
GASES
HEAT TRANSFER
HEATING
HYDRAULICS
HYDROGEN COMPOUNDS
MATHEMATICAL MODELS
MECHANICS
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PRESSURE DROP
SPACE
SPACERS
SUBCOOLED BOILING
VAPORS
WATER