Optimal nozzle spray cone angle for triangular-pitch shell-and-tube interior spray evaporator

Abstract The present study proposed a triangular-pitch shell-and-tube spray evaporator featuring an interior spray technique. In the proposed approach, the nozzle tubes are positioned within the tube bundle in such a way that the surface of each heater tube is sprayed simultaneously by two cooling sprays. As a result, the dry-out phenomenon is prevented, and thus the heat transfer performance is improved. An analytical expression is derived for the optimal spray cone angle for the proposed evaporator. It is shown that the optimal spray cone angle increases with an increasing diameter of the heater tubes, but decreases with an increasing distance between the heater tubes and nozzle tubes. The analytical expression for the optimal spray cone angle was validated by experimental spray tests using spray cone angles of 0°, 30°, 40°, 45° and 60°, respectively. It is shown that a good agreement exists between the experimental results for the optimal spray cone angle and the theoretical results. Furthermore, the experimental results confirm that the shell-side heat transfer coefficient obtained using the interior spray technique is significantly higher than that achieved in a conventional flooded-type evaporator over a wide range of surface heat fluxes.

[1]  T. Cader,et al.  Effect of Spray Angle in Spray Cooling Thermal Management of Electronics , 2004 .

[2]  M. Cooper.  SATURATION NUCLEATE POOL BOILING - A SIMPLE CORRELATION , 1984 .

[3]  M. Pate,et al.  The effects of nozzle height and orifice size on spray evaporation heat transfer performance for a low-finned, triangular-pitch tube bundle with R-134a , 1995 .

[4]  Arthur H. Lefebvre,et al.  Fuel Distributions from Pressure-Swirl Atomizers , 1985 .

[5]  Tong-Bou Chang,et al.  Effects of spray axis incident angle on heat transfer performance of rhombus-pitch shell-and-tube interior spray evaporator , 2012 .

[6]  L. Chow,et al.  HIGH HEAT FLUX SPRAY COOLING , 1997 .

[7]  J. P. Holman,et al.  Experimental methods for engineers , 1971 .

[8]  S. M. You,et al.  Boiling heat transfer phenomena from microporous and porous surfaces in saturated FC-72 , 1997 .

[9]  Ruey-Hung Chen,et al.  BUBBLE BEHAVIOR AND HEAT TRANSFER MECHANISM IN FC-72 POOL BOILING , 2001 .

[10]  Jenq-Shing Chiou,et al.  Heat Transfer Enhancement in a Spray Evaporator , 2005 .

[11]  G. Lorenzini,et al.  Experimental study of water droplet boiling on hot, non-porous surfaces , 1999 .

[12]  S. Yao,et al.  Analysis on film boiling heat transfer of impacting sprays , 1989 .

[13]  Louis C. Chow,et al.  Effect of surface material properties and surface characteristics in evaporative spray cooling , 1990 .

[14]  L. Chow,et al.  Surface Roughness and Its Effects on the Heat Transfer Mechanism in Spray Cooling , 1992 .

[15]  F. A. Wierum,et al.  Liquid spray cooling of a heated surface , 1981 .

[16]  S. Yao,et al.  Mechanisms of film boiling heat transfer of normally impacting spray , 1987 .

[17]  I. Mudawar,et al.  Optimizing and Predicting CHF in Spray Cooling of a Square Surface , 1996 .

[18]  Louis C. Chow,et al.  Effect of spray characteristics on spray cooling with liquid nitrogen , 1994 .

[19]  J. Chiou,et al.  Spray evaporation heat transfer of R-141b on a horizontal tube bundle , 1999 .

[20]  Louis C. Chow,et al.  Effects of Heater Orientation and Confinement on Liquid Nitrogen Pool Boiling , 2000 .

[21]  Marc E. Brown,et al.  Patent pending , 1995 .

[22]  Louis C. Chow,et al.  Bubble Behavior and Nucleate Boiling Heat Transfer in Saturated FC-72 Spray Cooling , 2002 .

[23]  A study of diamond laminated surfaces in evaporative spray cooling , 1992 .

[24]  S. Hsieh,et al.  Spray cooling characteristics of water and R-134a. Part II: transient cooling , 2004 .

[25]  J. Sunderland,et al.  Heat Transfer from a Spray-Cooled Isothermal Cylinder , 1968 .

[26]  Tong-Bou Chang,et al.  Heat Transfer Enhancement of Square-Pitch Shell-and-Tube Spray Evaporator Using Interior Spray Nozzles , 2011 .