Convective boiling heat transfer in a single micro-channel

The current industrial need for compact high heat density cooling devices has conveyed an increasing interest on convective boiling in micro-channels. Although there is general agreement that these systems may be able to dissipate potentially very high heat fluxes, their heat transfer characteristics are still unclear and require investigation. The present study aims at providing further insight on two-phase single micro-channel heat transfer, through a sensitivity analysis on the effect of the different operational parameters, fluid properties, and channel size on thermal performance. The current database includes results for three different refrigerants, R-134a, R-236fa and R-245fa, two channel diameters, 510 and 790µm, and a multitude of heat fluxes and mass velocities, for a total of over 1800 data points. Two-phase flow instability, which represents one of the factors that has prevented a well-established understanding of the micro-scale phenomenon, has been also investigated, with results showing the potential error it may induce on the estimation of the heat transfer coefficients. Finally, a one-dimensional analysis based on the effect of interfacial shear on the temporal evolution of film thickness is proposed for a heat transfer model for slug flow, which has been shown to be the dominant flow mode at low and intermediate vapor qualities in micro-channel evaporators.

[1]  Björn Palm,et al.  Flow boiling visualization in a vertical circular minichannel at high vapor quality , 2006 .

[2]  Shizuo Saitoh,et al.  Effect of tube diameter on boiling heat transfer of R-134a in horizontal small-diameter tubes , 2005 .

[3]  Tianshou Zhao,et al.  Co-current air–water two-phase flow patterns in vertical triangular microchannels , 2001 .

[4]  Wei Zhang,et al.  Transient flow pattern based microscale boiling heat transfer mechanisms , 2005 .

[5]  M. W. Wambsganss,et al.  Small circular- and rectangular-channel boiling with two refrigerants , 1996 .

[6]  Kunihito Matsumura,et al.  Saturated flow boiling of water in a vertical small diameter tube , 2003 .

[7]  I. Mudawar,et al.  Measurement and correlation of critical heat flux in two-phase micro-channel heat sinks , 2004 .

[8]  Albert Mosyak,et al.  Explosive boiling of water in parallel micro-channels , 2005 .

[9]  D. Kenning,et al.  Saturated Flow Boiling of Water in a Narrow Channel: Experimental Investigation of Local Phenomena , 2001 .

[10]  Satish G. Kandlikar,et al.  Heat Transfer Mechanisms During Flow Boiling in Microchannels , 2004 .

[11]  S. Garimella,et al.  Prediction of the onset of nucleate boiling in microchannel flow , 2005 .

[12]  Stuart W. Churchill,et al.  Correlating equations for laminar and turbulent free convection from a horizontal cylinder , 1975 .

[13]  G. Celata.  Special Issue dedicated to the ECI International Conference on Heat Transfer and Fluid Flow in Microscale: Castelvecchio Pascoli (Barga, Lucca), 25–30 September 2005 , 2006 .

[14]  T. Karayiannis,et al.  Examination of heat transfer correlations and a model for flow boiling of R134a in small diameter tubes , 2007 .

[15]  Mikio Suo,et al.  Two phase flow in capillary tubes , 1964 .

[16]  Min Chen,et al.  Experimental Study of Flow Boiling Heat Transfer in Mini-Tube , 2005 .

[17]  Jinliang Xu,et al.  Heat Transfer in Confined Forced-Flow Boiling , 2007 .

[18]  Neima Brauner,et al.  Identification of the range of ‘small diameters’ conduits, regarding two-phase flow pattern transitions , 1992 .

[19]  A. E. Bergles,et al.  On the Nature of Critical Heat Flux in Microchannels , 2003 .

[20]  S. Lin,et al.  Two-Phase evaporation of a refrigerant in a 1mm diameter tube , 2001 .

[21]  P. Griffith,et al.  A STUDY OF SYSTEM-INDUCED INSTABILITIES IN FORCED-CONVECTION FLOWS WITH SUBCOOLED BOILING. Technical Report No. 5382-35 , 1965 .

[22]  P. Kew,et al.  Correlations for the prediction of boiling heat transfer in small-diameter channels , 1997 .

[23]  G. M. Lazarek,et al.  Evaporative heat transfer, pressure drop and critical heat flux in a small vertical tube with R-113 , 1982 .

[24]  G. P. Peterson,et al.  Boiling nucleation and two-phase flow patterns in forced liquid flow in microchannels , 2005 .

[25]  John R. Thome,et al.  Heat Transfer Model for Evaporation in Microchannels, Part I: Presentation of the Model , 2004 .

[26]  Masahiro Kawaji,et al.  The effect of channel diameter on adiabatic two-phase flow characteristics in microchannels ☆ , 2004 .

[27]  Tim Ameel,et al.  Two-Phase Flow in Microchannels , 1997, Microelectromechanical Systems (MEMS).

[28]  John R. Thome,et al.  Heat Transfer Model for Evaporation of Elongated Bubble Flows in Microchannels , 2002 .

[29]  Fan-Gang Tseng,et al.  Bubble dynamics in microchannels. Part I: single microchannel , 2004 .

[30]  I. Mudawar,et al.  Two-phase flow in high-heat-flux micro-channel heat sink for refrigeration cooling applications: Part II—heat transfer characteristics , 2005 .

[31]  Jinliang Xu,et al.  On the Prediction of Heat Transfer in Micro-Scale Flow Boiling , 2007 .

[32]  Lounes Tadrist,et al.  Experimental study of unsteady convective boiling in heated minichannels , 2003 .

[33]  Tsing-Fa Lin,et al.  Evaporation heat transfer and pressure drop of refrigerant R-134a in a small pipe , 1998 .

[34]  W. Zhang,et al.  Correlation for flow boiling heat transfer in mini-channels , 2004 .

[35]  Said I. Abdel-Khalik,et al.  Gas–liquid two-phase flow in microchannels Part I: two-phase flow patterns , 1999 .

[36]  Chih-Ming Ho,et al.  Transport of bubbles in square microchannels , 2002 .

[37]  S. Lin,et al.  Two-phase heat transfer to a refrigerant in a 1 mm diameter tube , 2001 .

[38]  Jostein Pettersen,et al.  Flow vaporization of CO2 in microchannel tubes , 2004 .

[39]  D. Fletcher,et al.  Flow boiling heat transfer of Freon R11 and HCFC123 in narrow passages , 2000 .

[40]  B. Hamber.  Publications , 1998, Weed Technology.

[41]  S. Kandlikar,et al.  An Extension of the Flow Boiling Correlation to Transition, Laminar, and Deep Laminar Flows in Minichannels and Microchannels , 2004, Proceeding of Compact Heat Exchangers and Enhancement Technology for the Process Industries - 2003.

[42]  Jürgen Schmidt,et al.  Experimental investigation of transient boiling heat transfer in microchannels , 2007 .

[43]  S. Kandlikar.  Nucleation characteristics and stability considerations during flow boiling in microchannels , 2006 .

[44]  A. Bontemps,et al.  Vertical flow boiling of refrigerant R134a in small channels , 2005 .

[45]  John R. Thome,et al.  Characterization of diabatic two-phase flows in microchannels: Flow parameter results for R-134a in a 0.5 mm channel , 2006 .

[46]  Sohail Murad,et al.  A molecular dynamics simulation of droplet evaporation , 2003 .