Fujio Tachibana

Non-Hydrodynamic Aspects of Pool Boiling Burnout

More than 400 pieces of test sections—flat plates made of various metals and alloys—were placed in saturated water under atmospheric pressure and heated to physical destruction by passing electric current directly through them. Several non-hydrodynamic parameters have marked effect upon the critical heat flux, which indicates that purely hydrodynamic theories are not directly applicable to general prediction of the critical heat flux. The critical heat flux data was found to be well correlated with the heat capacity per unit surface area of the test section: the critical heat flux is reduced with decrease of this parameter, while with increasing parameter it approaches a certain asymptotic value. The fluctuation of surface temperature due to alternate contact with vapor and liquid was calculated by the proposed model, and the trend of dryout duration was estimated from the critical heat flux data.

Heat Transfer and Critical Heat Flux in Transient Boiling, (I): An Experimental Study in Saturated Pool Boiling

Heat transfer and critical heat flux in saturated pool boiling were experimentally studied under transient power condition. The heating elements were flat plates of nickel submerged facing vertical...

MEASUREMENT OF HEAT TRANSFER COEFFICIENTS FOR AXIAL AIR FLOW THROUGH ECCENTRIC ANNULUS AND SEVEN-ROD CLUSTER.

The heat transfer characteristics of non-concentric annuli with various eccentricities and also of a seven-rod cluster were experimentally determined by means of mass transfer technique. A coating of naphthalene was applied to the surface of the test rod and changes in its thickness measured. The mass transfer coefficients have been represented in terms of Colburns j-factor, with which both the average and local values were analyzed. The measured average heat transfer j-factors were found to be in part equal to those for smooth round ducts, but the circumferential variations of the local factors for the eccentric annulus did not agree with the theoretical prediction proposed by Dwyer & Yu. The existence of secondary flow in the seven-rod cluster is also discussed.