Study of Post Dryout Heat Transfer in Annulus With Flow Obstacles

Abstract

The purpose of this paper is to present the experimental setup, experimental method and results of the recent post-dryout heat transfer investigations in an annulus with pin spacers. The experiments were performed in the thermal-hydraulic laboratory at the Royal Institute of Technology (KTH), Stockholm, Sweden. The experimental facility has an annular test section which consists of two double-heated concentric tubes manufactured of Inconel 600. Five levels of pin spacers were installed along the test section to keep the rod and the tube equidistant during experiments. The experimental matrix includes measurements of wall temperature distributions for single phase and two-phase flows, for both convective boiling and post-dryout heat transfer regimes. The influence of variations in mass flux (500–1500) kg/(m2s) and inlet subcooling 10 and 40 K at system pressure of 7 MPa were investigated. The experimental results indicate that post dryout heat transfer is influenced by the pin spacers. In particular it has been observed that the dry patch appearing in the test section can be quenched downstream of the pins-spacer. The current results provide additional experimental database which can be used for validation of post-dryout heat transfer models including the flow obstacle effects.

Experimental investigation of post-dryout heat transfer in annuli with flow obstacles

“…The present experiments employ an annular test section in which the inner rod is supported with pin spacers, and two additional flow obstacles are inserted to measure their net effect on the post-dryout heat transfer. The test section has been instrumented with 88 thermocouples to allow for a significant improvement of the accuracy of measurements, as described in Anghel et al (2010). Due to the high accuracy of measurements and thanks to the performed analysis of error propagation, the present measurements are suitable for validation of computational models of post-dryout heat transfer.…”