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Heat Transfer Handbook part 70

Heat Transfer Handbook part 70. The Heat Transfer Handbook provides succinct hard data, formulas, and specifications for the critical aspects of heat transfer, offering a reliable, hands-on resource for solving day-to-day issues across a variety of applications. | 684 BOILING Vapor quality Figure 9.16 Simulation of Kattan-Thome-Favrat model for pure n-butane at 60 C showing flow pattern map and heat transfer coefficients. Fully stratified flow for m 20kg m2 s at all x values with a monotonic decrease in atp with increasing x Stratified-wavy flow for m 60kg m2 s at all x values shown that give a moderate peak in atp versus x Intermittent flow for m 200 kg m2 s with x 0.4 that shows a moderate rise in atp versus x FLOW BOILING IN HORIZONTAL TUBES 685 Annular flow for m 200kg m2 s with 0.4 x 0.93 that results in an ever-steeper rise in atp versus x as the annular film thins out before tee nnset of dryout occurs at x 0.93 Annular flow with partial dryout modeled as stratifled-wavy flow for m 200kg m2 s with x 0.93 where a sharp decline in atp versus x after the peak occurs Although not illustrated atp goes to its natural limit of avapor at x 0. On the other hand lor ill liuuifl flow hhe covvcctive boihgg heat traerfco efiofl 010111 acb for liquid film flow does not go to the tubular u . Hence acb should be obtained with the Dittus-Boelter or Gnielinski correlation when x 0. Including more recent data for evaporation ff ammonra fom mast s elocieer as tow as 16.3 kg m2 s and results for evaporation of refrigerant-oil mixtures their flow boiling model is applicable over the following parameter ranges S.S2 p t 8.9 bar 0.0085 pr 0.225 S6.3 m 500kg m2 s 0.0S x S.0 440 q 7S 600W m2 S7.03 M S52.9 but up to about 300 for refrigerant-oil mixtures 74 ReL 20 399 and S300 ReG 376 804 S.85 PrL 5.47 but up to S34 for refrigerant-oil mixtures 0.000S6 14. 0.035N s m2 i.e. 0.S6 to 35 cP Tube metals copper carbon steel and stainless steel For annuaar owws toe cccuraco of thin nww method is rimrrac to toesc of toe ahah S982 Jung et al. S989 and Gungor-Winterton S986 S987 correlations however the latter methods do not provide a method to determine when annular flow conditions exist. For stratifled-wavy flows the Kattan-Thome-Favrat model has been .