ANALYSIS OF CRITERION RELATIONSHIPS FOR LIQUIDS BOILING IN TUBES. (UTOCHENIE KRITERIAL'NYKH ZAVISIMOSTEI PRI KIPENII ZHIDKOSTEI V TRUBAKH
MINISTRY OF AVIATION LONDON (UNITED KINGDOM)
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A study was made of the heat exchange process in boiling highly concentrated sugar solutions with natural circulation and interchangeable heating tubes of 159150, 9587 and 5748 mm in diameter, the sugar content being 0, 60, 75, 82 and 86, the pressure varying from 0.4 to 1.0 atm. abs. with a depth of immersion of the heating surface of up to 200. The experiments, carried out for a sufficiently wide range of variations of kinema tic viscosities, allowed of ascertaining the effect of the viscosity on the heat transfer coefficient and of determining the values of the Ga and Pr power indices in the M. A. Kichigin N.Y. Tobilevich and in the V.I. Tolubinskii criterial systems. The new experimental data made it possible to obtain a corrected criterion equation for the M.A. Kichigin-N.Y. Tobilevich system and a corrected criterion formula for the V.I. Tolubinskii system, and to extend the applicable range of these formulae for Prandtl numbers ranging from 0.7 to 1540. Since the M.A. Kichigin-N.Y. Tobilevich corrected criterion system yields a smaller error in generalising experimental data relating to a large group of experimental substances and is valid in a wide variational range of factors affecting the heat transfer in boiling liquids, its application should be given preference, at least at the present stage of progress, in the study of the heat exchange processes in boiling.