Accession Number : AD0461028

Title :   PRESSURE DROP WITH SURFACE BOILING IN SMALLDIAMETER TUBES.

Descriptive Note : Technical rept.,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF MECHANICAL ENGINEERING

Personal Author(s) : Dormer, Thomas, Jr. ; Bergles, Arthur E.

Report Date : 01 SEP 1964

Pagination or Media Count : 85

Abstract : Pressure drop for water flowing in small-diameter tubes under isothermal, nonboiling, and surfaceboiling conditions was investigated. Experimental results for local pressure gradient and heat-transfer coefficients are presented. Heattransfer results for non-boiling and surface boiling are in agreement with previous investigations. Isothermal friction factors compare favorably with conventional smooth-tube data. Nonboiling friction factors were well correlated with a wall-to-bulk fluid viscosity ratio. It is concluded that boiling pressure gradients cannot be correlated on the basis of local conditions alone. The axial build up of nonequilibrium vapor in the tube produces an increase in pressure gradient even when all other local parameters are constant. The heattransfer - pressure-gradient analogy was investigated in the boiling region. For the chosen boiling-to-nonboiling ratios, the analogy was found to be valid only under limited conditions. Overall pressure-drop data are presented for numerous geometries and a range of flow conditions. Diameters of 0.062 to 0.180 in. and L/D's of 25 to 200 were considered. Exit pressures ranged from 30 to 80 psia and velocities ranged from 5 to 50 ft/sec. The majority of the data was taken for an inlet temperature of 80F. (Author)

Descriptors :   (*PIPES, PRESSURE), (*BOILING, HEAT TRANSFER), SURFACES, INSTRUMENTATION, SURFACE TEMPERATURE, MANOMETERS, CYLINDRICAL BODIES, EXPERIMENTAL DATA.

Distribution Statement : APPROVED FOR PUBLIC RELEASE