Falling water film evaporation on newly-designed enhanced tube bundles

Experimental studies are presented on falling film evaporation of water on 6-row horizontal enhanced tube bundles in a vacuum condition. Turbo-CAB (19 fpi and 26 fpi), Korodense, and smooth tubes were tested in a range of film Reynolds number from about 10 to 110 and in the condition of only convective evaporation, without nucleate boiling. The flow modes and heat flux will affect the transition Reynolds numbers. Tubes with enhanced inner surface provide better heat transfer performance. Hotter heating water may lead to better heat transfer performance mainly due to higher heat fluxes. Correlations were also derived to predict the heat transfer coefficients and the enhancement ratio.

[1]  M. M. Awad,et al.  ENHANCEMENT OF EVAPORATION OF FALLING LIQUID FILM ON HORIZONTAL TUBE BUNDLE , 2008 .

[2]  Zhen-hua Liu,et al.  Falling film evaporation heat transfer of water/salt mixtures from roll-worked enhanced tubes and tube bundle , 2002 .

[3]  Je-Chin Han,et al.  Heat Transfer Through Falling Film Evaporation and Boiling on Horizontal Tubes , 1990 .

[4]  V. Sernas,et al.  EVAPORATION HEAT TRANSFER COEFFICIENTS FOR THIN SEA WATER FILMS ON HORIZONTAL TUBES , 1975 .

[5]  J. Thome,et al.  Experimental study on the onset of local dryout in an evaporating falling film on horizontal plain tubes , 2007 .

[6]  E. N. Sieder,et al.  Heat Transfer and Pressure Drop of Liquids in Tubes , 1936 .

[7]  John R. Thome,et al.  Falling Films on Arrays of Horizontal Tubes with R-134a, Part II: Flow Visualization, Onset of Dryout, and Heat Transfer Predictions , 2007 .

[8]  K. A. Tagavi,et al.  The Role of Surface Tension in Film Condensation in Extended Surface Passages , 1999 .

[9]  Shengqiang Shen,et al.  Experimental study of falling film evaporation heat transfer outside horizontal tubes , 2008 .

[10]  Anthony M. Jacobi,et al.  Falling-film evaporation on horizontal tubes—a critical review , 2005 .

[11]  Masayuki Tsutsui,et al.  Experimental investigation of falling film evaporation on horizontal tubes , 1996 .

[12]  Anthony M. Jacobi,et al.  The intertube falling film: Part 1 - Flow characteristics, mode transitions, and hysteresis , 1996 .

[13]  V. L. Podberezny,et al.  Evaporation heat transfer in liquid films flowing down horizontal smooth and longitudinally profiled tubes , 1996 .

[14]  Anthony M. Jacobi,et al.  The intertube falling film: Part 2-Mode effects on sensible heat transfer to a falling liquid film , 1996 .