EXPERIMENTAL INVESTIGATION OF STATIONARY AND TRANSIENT POST-DRYOUT HEAT TRANSFER IN 22.1X10 MM ANNULUS WITH SPACERS

• Experimental investigation of the post-dryout heat transfer in annulus test section has been performed in the high-pressure two-phase loop at the Royal Institute of Technology (KTH). The test section has an annular geometry with 10 mm rod outer diameter and 22.1 mm tube inner diameter. Seven spacers are located along the test section to keep the rod and the tube equidistant along the test section. Both the tube and the rod are manufactured of Inconel 600 to withstand high temperatures. Several thermocouples have been installed on the tube and the rod surface to measure the local temperature.The measurements have been performed for a wide range of the inlet mass flow rate, keeping the inlet subcooling equal to 10 K and the pressure to 70 bars. Uniform axial power distributions have been applied on the rod and tube walls, however, several different ratios between the heat fluxes on the two surfaces have been applied. Both steady-state and transient measurements have been performed in which axial distribution of wall temperatures have been registered.The experiments indicate a very strong influence of spacers on post-dryout heat transfer. In particular, for several cases with relatively low local quality the dryout spot is limited to a direct proximity of spacers, stretching from approximately 10 cm upstream of the spacer to 5 cm downstream of the spacer. Only for relatively high powers the dryout patch could cover the whole distance between two neighboring spacers.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Energiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Energy Engineering (hsv//eng)

Nyckelord

Post-dryout

spacer influence

annulus

heat transfer

SRA - Energy

SRA - Energi

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