Effect of system pressure on film-boiling heat transfer, minimum heat flux, and minimum temperature

Journal Article · Thu Nov 01 04:00:00 EST 1984 · Nucl. Sci. Eng.; (United States)

OSTI ID:6214098

Sakurai, A; Hata, K; Shiotsu, M

Film-boiling heat transfer on a horizontal test heater in a pool of saturated and subcooled water was investigated at pressures ranging from 20 kPa to 2 MPa. Platinum rods of 0.7, 1.2, 2, 3, and 5 mm in diameter were used as the test heater. A semiempirical equation and a modified Bromley equation were given, both of which could express the saturated film-boiling heat transfer coefficients within + or - 5% error. The heat transfer coefficients for a certain range of heater diameters under saturated and subcooled conditions were expressed within + or - 10% error by the two-phase boundary-layer film-boiling model with the boundary condition of equal liquid and vapor interfacial velocities. Pressure dependence of the minimum film-boiling temperature for pressure <1.1 Mpa was clearly different from that for pressure > 1.1 MPa. Minimum temperature in the lower pressure region seems to be determined by the hydrodynamic Taylor instability and that in the higher pressure region by the heterogeneous spontaneous nucleation limit. However, minimum temperature and heat flux of saturated film boiling in the former region did not agree with those of conventional equations based on the Taylor instability. Empirical equations of interfacial wave length, departing bubble diameter, and frequency near the minimum film-boiling temperature for the lower pressure region were given. Minimum temperature and heat flux equations were presented based on these empirical equations.

• Research Organization: Kyoto Univ., Kyoto
• OSTI ID: 6214098
• Journal Information: Nucl. Sci. Eng.; (United States), Journal Name: Nucl. Sci. Eng.; (United States) Vol. 88:3; ISSN NSENA
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420400* -- Engineering-- Heat Transfer &amp; Fluid Flow
APPLIANCES
BOILING
BOUNDARY CONDITIONS
BUBBLES
COOLING
ENERGY TRANSFER
EQUATIONS
FILM BOILING
FLOW RATE
FLUID FLOW
FLUID MECHANICS
FREQUENCY DEPENDENCE
HEAT FLUX
HEAT TRANSFER
HEATERS
HYDRODYNAMICS
MECHANICS
NUCLEATION
PHASE TRANSFORMATIONS
PRESSURE EFFECTS
RODS
SATURATION
SUBCOOLING
TEMPERATURE EFFECTS
TWO-PHASE FLOW
WATER HEATERS
WAVELENGTHS