Spatial and temporal variation of the surface temperature and heat flux for saturated pool nucleate boiling at lower heat fluxes
The spatial and temporal variations of local surface temperature and heat flux for saturated pool nucleate boiling are investigated parametrically using a numerical model. The numerical model consisted of solving the three-dimensional transient heat conduction equation within the heater subjected to nucleate boiling over its upper surface. The surface topography model to distribute the cavities over the boiling surface used a Monte Carlo scheme. All cavities were assumed to be conical in shape. The cavity radii are obtained using an exponential probability density function with a known mean value. Local surface temperatures showed significant spatial and temporal variations, depending upon the surface topography and the heater material and thickness. However, the surface-averaged temperature showed practically no temporal variation. The temporal variations in local temperatures caused the surface-averaged heat flux to vary significantly. The temporal variations in the surface-averaged heat flux were similar for smooth and rough and thick and thin copper and nickel plates. Results indicated that the use of a classical energy balance equation to evaluate the surface heat flux must consider the spatial variation of the temperature. Results also showed that any thermocouple embedded beneath the surface of the heater does not follow the temporal variations at the surface.
- Research Organization:
- Los Alamos National Lab., NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 10102480
- Report Number(s):
- LA-UR-93-3298; CONF-940625-1; ON: DE94000897; IN: N--6-93-R139; TRN: 94:007202
- Resource Relation:
- Conference: 6. AIAA/ASME thermophysics and heat transfer conference,Colorado Springs, CO (United States),20-23 Jun 1994; Other Information: PBD: [1993]
- Country of Publication:
- United States
- Language:
- English
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