Subcooled Boiling Near a Heated Wall

Technical Report · Fri Oct 27 04:00:00 EDT 2000

DOI:https://doi.org/10.2172/821308· OSTI ID:821308

Trabold, T A; Maneri, C C; Vassallo, P F; Considine, D M

Experimental measurements of void fraction, bubble frequency, and velocity are obtained in subcooled R-134a flowing over a heated flat plate near an unheated wall and compared to analytical predictions. The measurements were obtained for a fixed system pressure and mass flow rate (P = 2.4 MPa and w = 106 kg/hr) at various inlet liquid temperatures. During the experiments, electrical power was applied at a constant rate to one side of the test section. The local void fraction data, acquired with a hot-film anemometer probe, showed the existence of a significant peak near the heated wall and a smaller secondary peak near the unheated wall for the larger inlet subcoolings. Local vapor velocity data, taken with the hot-film probe and a laser Doppler velocimeter, showed broad maxima near the centerline between the heated and unheated plates. Significant temperature gradients near the heated wall were observed for large inlet subcooling. Bubble size data, inferred from measurements of void fraction, bubble frequency and vapor velocity, when combined with the measured bubble chord length distributions illustrate the transition from pure three dimensional spherical to two-dimensional planar bubble flow, the latter being initiated when the bubbles fill the gap between the plates. These various two-phase flow measurements were used for development of a multidimensional, four-field calculational method; comparisons of the data to the calculations show reasonable agreement.

• Research Organization: Lockheed Martin Corporation, Schenectady, NY 12301 (US)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: AC12-00SN39357
• OSTI ID: 821308
• Report Number(s): LM-00K084
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
ANEMOMETERS
BUBBLES
FLOW RATE
LASERS
PLATES
PROBES
SUBCOOLED BOILING
SUBCOOLING
TEMPERATURE GRADIENTS
TWO-PHASE FLOW
VELOCITY
VOID FRACTION