7.11. Observations

We have presented a summary of CHF with an emphasis on the fundamental mechanisms of CHF. It is important to remember that one must use empirical correlations only within their range of applicability, and if correlations do not exist to use available data in a manner suggested to develop the engineering correlations. One area which has little data to support development is transient critical heat flux (e.g., Moxon and Edwards (1967)). The general observation from this limited data is that under transient conditions tends to be larger than CHF under similar steady-state conditions. It is therefore recommended that consideration of CHF being exceeded under transients (flow or power) be based on local conditions and employing appropriate steady state correlations.

References

• G.V. Alekseev, "Burnout Heat Fluxes Under Forced Flow," Proc. of Third Int'l Conference on Peaceful Uses of Atomic Energy, Geneva, August 1964.
• F. Biancone, et al., "Forced Convection Burnout and Hydrodynamic Instability Experiments for Water at High Pressure Pt. I." EUR 2490e, 1965.
• R.W. Bowring, "A Simple But Accurate Round Tube, Uniform Heat Flux, Dryout Correlation Over the Pressure Range 0.7-17 MN/M2." AEEW-R789, 1972.
• J.E.Casterline, "Burnout in Long Vertical Tubes With Uniform and Casine Heating Using Water at 1000 Psia," Topical Rep No. 1. Task XVI Columbia University 1964 (TID 2103) also Topical Rep No. 5 , "Second Experimental Study of Dryout in a Long Vertical Tube With a Cosine Heat Flux."
• J.G. Collier, "Convective Boiling and Condensation," McGraw Hill Publishers, NY, 1972.
• M.P. Fiori and A.E. Bergles, "Model of Critical Heat Flux in Sub-Cooled Flow Boiling." MIT Report - DSR70281-56, 1968.
• G.P. Gaspari, A. Hassid and F. Lucchini, "A Rod Centered Sub-channel Analysis With Turbulent (enthalpy) Mixing for Critical Heat Flux Prediction in Rod Clusters Cooled by Boiling Water." Proc. 5th Int Heat Transfer Conf., 4, 295-299, 1974.
• A.Jensen and G. Mannov, "Measurements of Burnout, Film Flow Film," 1974.
• G.J.Kirby, "A New Correlation of Non-Uniformly Heated Round Tube Burnout Data." AEEW-R500, 1966.
• J.F. Kirby, R. Staniforth and L.H. Kinneir, "A Visual Study of Forced Convective Boiling." Part II: Flow Patterns and Burnout for a Round Test Section," AEEW-R506, 1967.
• D.H. Lee and J.D. Obertelli, "An Experimental Investigation of Forced Convection Burnout in High Pressure Water - Pt. II." AEEW-R309, 1963.
• D.H. Lee, "An Experimental Investigation of Forced Convection Burnout in High Pressure Water - Pt. III," AEEW-R355 , 1965.
• D.H.Lee, "An Experimental Investigation of Forced Convection Burnout in High Pressure Water - Pt. IV." AEEW-R479, 1966.
• J.H.Lienhard and R. Eichhorn, "Peak Boiling Heat Flux on Cylinders in a Cross Flow." Int J Heat Mass Transfer, 19, No. 20, 1135-1141, 1976.
• D. Moxon and P.A.Edwards, "Dry Out During Flow and Power Transients." AEEW-R553, 1967.
• G.F. Stevens and G.J. Kirby, "A Quantitative Comparison Between Burnout Data for Water at 1000 lb/ and Freon 12 at 155 lb/ (abs) and by Water at 1000 lb/ in Vertical Upflow." AEEW-R327, 1964.
• G.F. Stevens and R.W. Wood, "A Comparison Between Burnout Data for 19 Rod-Cluster Test Sections Cooled by Freon 12 at 155 lb/ (abs) and by Water at 1000 lb/ in Vertical Upflow." AEEW-R468, 1966.
• H.S. Swenson, R.J. Carver and C.R.Kakarala, "The Influence of Axial Heat Flux Distribution on the Departure From Nucleate Boiling in a Water-Cooled Tube." Paper presented to the Winter Annual Meeting of the ASME, Nov 1962, New York. Paper 62-WA-297, 1962.
• H.S. Swenson, et al., "Non-Uniform Heat Generation Experimental Programme." QPR Nos. 4, 5, 6, 7 and 8, BAW-3238, 1964.
• N.E Todreas and W.M. Rohsenow, "The Effect of Non-Uniform Axial Heat Flux Distribution," M.I.T.-9843-37; see also paper to 1966 Int. Heat Transfer Conf., Chicago, paper 89, 1965.
• L.S. Tong and G.F. Hewitt, "Overall View Point of Film Boiling CHF Mechanisms," ASME Paper No. 72-HT-54, 1972.
• L.S. Tong, H.B. Currin and T.S. Larsen, "Influences of Axially Non-Uniform Heat Flux on DNB." WCAP-2767. Published in CEP Symp Ser, 62 (64), 1966.