Effects of the spacer and mixing vanes on critical heat flux for low-pressure water at low-velocities

Journal Article · Tue Oct 01 04:00:00 EDT 1996 · International Communications in Heat and Mass Transfer

DOI:https://doi.org/10.1016/0735-1933(96)00059-0· OSTI ID:372284

Chung, J B; Baek, W P; Chang, S H ^[1]

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1. Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of). Dept. of Nuclear Engineering

The effects of spacer grids and mixing vanes on critical heat flux (CHF) have been experimentally investigated for low-pressure water at low, using two different types of test sections: an annulus (19-mm I.D., 33.5-mm O.D., 0.7-m long) and a round tube (10.8-mm I.D. and 0.7-m long). An obstruction-type spacer and a split-vane-type mixing vane were used for the annulus and round tube test sections, respectively. The spacer or mixing vane generally increase the CHF for flow rates higher than a threshold; however, they do not affect or even decrease the CHF under lower flow rates. The major contributing mechanisms would be (a) directing entrained liquid droplets to the heated wall (positive effect) and (b) break-up of the liquid film in annular flow (negative effect).

• OSTI ID: 372284
• Journal Information: International Communications in Heat and Mass Transfer, Journal Name: International Communications in Heat and Mass Transfer Journal Issue: 6 Vol. 23; ISSN 0735-1933; ISSN IHMTDL
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
AUGMENTATION
CRITICAL HEAT FLUX
FUEL ELEMENT CLUSTERS
TUBES
TURBULENT FLOW