Convective boiling in vertical channels with different offset strip fin geometries
- Univ. of California, Berkeley (USA)
Newly obtained local heat transfer data are presented for flow boiling of liquids in two partially heated vertical channels with different offset strip fin geometries operating at low to moderate wall superheat levels. Experiments were conducted in special test sections that permitted direct visual observation of the boiling process while simultaneously measuring the heat transfer coefficient along the channel. Data for which nucleate boiling appeared to be completely suppressed were analyzed together with similar results for other offset fin geometries to assess the effects of channel geometry variations on the two-phase heat transfer coefficient during annular film-flow evaporation. For all geometries, the data for annular film-film evaporation were found to correlate well in terms of modified versions of the F and Martinelli parameters used by Bennett and Chen (1980) to correlate similar data for round tubes. For fin matrices of similar size and configuration, the forced convective component of the two-phase heat transfer coefficient was found to be well represented by a single F-parameter correlation curve. however, F-factor correlations for matrices having significant differences in fin and channel dimensions were found to differ substantially. An approximate superposition method for including the contribution of nucleate boiling to the two-phase heat transfer coefficient at low to moderate wall superheat levels is also proposed.
- OSTI ID:
- 5386442
- Journal Information:
- Journal of Heat Transfer (Transcations of the ASME (American Society of Mechanical Engineers), Series C); (United States), Vol. 111:1; ISSN 0022-1481
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
HEAT EXCHANGERS
FINS
AIR CONDITIONING
BOILING
CHEMICAL PREPARATION
CONVECTION
DATA
EVAPORATION
FILM FLOW
REFRIGERATION
TWO-PHASE FLOW
COOLING
ENERGY TRANSFER
FLUID FLOW
HEAT TRANSFER
INFORMATION
MASS TRANSFER
PHASE TRANSFORMATIONS
SYNTHESIS
420400* - Engineering- Heat Transfer & Fluid Flow
320106 - Energy Conservation
Consumption
& Utilization- Building Equipment- (1987-)