Heat transfer to droplets impinging upon superheated surfaces

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:7249681

Ksu, K K

Transient surface temperature traces were obtained for a block when impinged upon by a water droplet under different experimental conditions. The temperature measurement relied on successful electro-plating over a surface thermal probe. Instantaneous heat flux from the metal block to the impacting droplet was derived through inverse conduction calculation. Four relevant parameters (degree of wall superheat, degree of droplet subcooling, impinging velocity and droplet size) were experimentally tested to study their effects on the droplet quenching process. The experimental data indicates the following: (1) for a dynamic impingement, the occurrence of liquid contact with a solid beyond Leidenfrost temperature was experimentally confirmed. (2) Heat transfer between droplet and wall surface were significantly affected by the degrees of wall superheat and droplet subcooling. The effects of impinging velocity and droplet size were obscure in the test ranges. (3) Boiling curves were established for this special droplet quenching process. It consisted of two regions: a nucleate-boiling-like region and a transition region. In the nucleate-boiling-like region, the heat transfer rate varied with wall superheat only and was close to Miyasaka et al.'s subcooled pool boiling data. In the transition region, heat transfer depended on both wall superheat and droplet subcooling.

• Research Organization: Lehigh Univ., Bethlehem, PA (USA)
• OSTI ID: 7249681
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420400* -- Engineering-- Heat Transfer & Fluid Flow
BOILING
DROPLETS
ELEMENTS
ENERGY TRANSFER
HEAT TRANSFER
HEATING
HYDROGEN COMPOUNDS
METALS
NUCLEATE BOILING
OXYGEN COMPOUNDS
PARTICLES
PHASE TRANSFORMATIONS
SUPERHEATING
SURFACES
TRANSITION BOILING
WATER