Jet impingement boiling from a circular free-surface jet during quenching: Part 1 - Single-phase jet

This paper reports results from an experimental study of boiling heat transfer during quenching of a cylindrical copper disk by a subcooled, circular free-surface water jet. The disk was heated to approximately 650 degreesC, and as quenching occurred, transient temperature measurements were taken at discrete locations near the surface and applied as boundary conditions in a conduction model to deduce transient heat flux distributions at the surface. Results are presented in the form of heat flux distributions and boiling curves for radial locations varying from the stagnation point to ten nozzle diameters for jet velocities between 2.0 and 4.0 m/s (11,300 less than or equal to Re(d)less than or equal to 22,600). Data for nucleate boiling in the stagnation region and spatial distributions of maximum heat flux are presented and are in good agreement with correlations developed from steady-state experiments. Spatial distributions of minimum film boiling temperatures and heat fluxes are also reported and reveal a fundamental dependence on jet deflection and streamwise location. A companion paper (Hall et al., 2001) describes single-phase and boiling heat transfer measurements from a two-phase (water-air), free-surface, circular jet produced by injecting air bubbles into the jet upstream of the nozzle exit.