Characteristics of Transition Boiling in Sodium-Heated Steam Generator Tubes

Carlson, R.D.; Chiang, Tung‐Liang; Priemer, R.

doi:10.1115/1.3450959

Cited by 13 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because of the close proximity of these thermocouples to the water-wall interface, the temperature oscillations observed were now much larger (30°C) than those previously seen with the round tube test section. The magnitude and frequency of the temperature oscillations were very similar to those previously seen in the Argonne National Lab steam generator tests (France et al, 1979(France et al, , 1982. Figure 2 shows three typical temperature response curves From a couple which was in the transition region.…”

Section: Experimental Program and Resultssupporting

confidence: 75%

See 1 more Smart Citation

A moving‐front transition boiling model

Kao

Weisman

1985

AIChE Journal

View full text Add to dashboard Cite

In accordance with visual observations, a transition boiling model that assumes a quench front which alternately advances and retreats in the water flow direction, is proposed. With appropriate choice of a quench zone width and heat transfer rate when the surface is wet, the model predictions are in the same range as the observed temperature oscillations. SCOPEHeater wall temperature oscillations are characteristic of transition boiling. In flow boiling, the mechanism governing transition boiling depends on the volume fraction of vapor present. At high vapor volume fractions, annular flow occurs and a thin film of liquid is present on the wall during nucleate boiling. Transition boiling behavior at high volume fractions is governed by behavior in the region where this liquid film disappears.In accordance with visual observations and temperature measurements, it was postulated that at high vapor fractions the characteristic temperature fluctuations are caused by the vertical oscillation of the edge of the liquid film on the heater surface. The temperature oscillations computed from this moving front model were compared with experimental observations taken in a test section heated by hot mercury.The observed temperature oscillations were also used to estimate wetted area fractions during transition boiling. By relating these wetted area fractions to the aforementioned analytical model, a means for prediction of transition boiling heat transfer rates in the mercury-heated test section was developed. CONCLUSIONS AND SIGNIFICANCEThe present work strongly supports the assumption that transition boiling temperature fluctuations in flowing systems at high vapor fractions are caused by vertical oscillations of the wetting front. Not only is this model in accord with recent visual observations, but it leads to predictions of wall temperature oscillations whose magnitudes are in general agreement with measurements. Further, it explains the high crosscorrelation coefficient between temperature variations at the same axial elevation but different circumferential locations. The model also leads to heat transfer coefficient predictions which are in

show abstract

Section: Experimental Program and Resultssupporting

confidence: 75%

“…Argonne National Laboratory (France et al, 1979) measured the wall temperature oscillations seen at high vapor fractions during their tests of a sodium-heated steam generator. In their analysis of the Argonne data, Chu et al (1978) adopted a model originally suggested by Hewitt et al (1963).…”

Section: Conclusion and Significancementioning

confidence: 99%