Numerical simulation of sub-cooled boiling flow with fouling deposited inside channels

In this article, a numerical simulation has been performed to investigate the sub-cooled boiling flow in axisymmetric channels using the two-phase particle model. The equivalent diameter of the channel is 4.38 mm with 365.7 cm in length. The fouling deposited layer is filled with subsequent two-thirds of the flow channel. The internal surface of the channel is covered by a fouling deposit layer with a thickness ranging from 0.225 mm to 1.55 mm. Uniform heat flux of 29267.6 W/m2 is applied on the heated wall. Validation of the CFD model is carried out through comparison with open published experimental data and a close agreement is achieved. A new parameter, Security factor, is introduced and defined in the current study. Numerical results show that the developed two-phase particle model could well predict the water-steam two-phase change flow. The Nusselt number in the fouling region without fouling deposited could be 50 times higher than that with fouling layer. The heat transfer performance of the channel with thickness of 0.225 mm fouling deposit layer is 5 times larger than that with thickness of 1.55 mm fouling deposit layer. It is also found that the inlet velocity has significant impact on the boiling and total pressure drops along the channel.

[1]  K. Urbaniec,et al.  Validation of the method for determination of the thermal resistance of fouling in shell and tube heat exchangers , 2013 .

[2]  G. Hewitt,et al.  Flow boiling of water in a vertical tube at sub-atmospheric pressures , 2007 .

[3]  M. S. Abd-Elhady,et al.  Minimum gas speed in heat exchangers to avoid particulate fouling , 2004 .

[4]  Soojin Jun,et al.  A 2D dynamic model for fouling performance of plate heat exchangers , 2006 .

[5]  Yanhua Yang,et al.  Numerical simulation of film boiling on a sphere with a volume of fluid interface tracking method , 2008 .

[6]  Sepehr Sanaye,et al.  Simulation of heat exchanger network (HEN) and planning the optimum cleaning schedule , 2007 .

[7]  Krzysztof Urbaniec,et al.  Optimal cleaning schedule for heat exchangers in a heat exchanger network , 2005 .

[8]  H. K. Varma,et al.  Boiling heat transfer in small horizontal tube bundles at low cross-flow velocities , 1995 .

[9]  R. Pastuszko.  Boiling heat transfer enhancement in subsurface horizontal and vertical tunnels , 2008 .

[10]  Abdelkader Mouheb,et al.  A dynamic model for milk fouling in a plate heat exchanger , 2009 .

[11]  Quamrul H. Mazumder,et al.  CFD Analysis of Single and Multiphase Flow Characteristics in Elbow , 2012 .

[12]  W. Rohsenow,et al.  Nucleate pool-boiling heat transfer. I: review of parametric effects of boiling surface , 2004 .

[13]  Lei Wang,et al.  Modeling of low-pressure subcooled boiling flow of water via the homogeneous MUSIG approach , 2009 .

[14]  Vassilios S. Vassiliadis,et al.  Identifying optimal cleaning cycles for heat exchangers subject to fouling and ageing , 2012 .

[15]  Eckhard Krepper,et al.  CFD for subcooled flow boiling: Simulation of DEBORA experiments , 2011 .

[16]  J. T. Rogers,et al.  The Thermal Hydraulics of Tube Support Fouling in Nuclear Steam Generators , 2004 .

[17]  Shalendra Kumar,et al.  Boiling heat transfer from a vertical row of horizontal tubes , 2002 .

[18]  Nikolay Ivanov Kolev.  How accurately can we predict nucleate boiling , 1995 .

[19]  S. Kandlikar,et al.  Development of a Flow Boiling Map for Subcooled and Saturated Flow Boiling of Different Fluids Inside Circular Tubes , 1991 .

[20]  T. Hibiki,et al.  Some characteristics of air-water two-phase flow in small diameter vertical tubes , 1996 .

[21]  Zhen Yang,et al.  Numerical and experimental investigation of two phase flow during boiling in a coiled tube , 2008 .

[22]  Gretar Tryggvason,et al.  Direct Numerical Simulations of Flows with Phase Change , 1996 .

[23]  Peter J. Fryer,et al.  Engineering and chemical factors associated with fouling and cleaning in milk processing , 1997 .

[24]  J. Taborek,et al.  Flow Boiling Heat Transfer in Vertical Tubes Correlated by an Asymptotic Model , 1992 .

[25]  B. Shannak,et al.  Frictional pressure drop of gas liquid two-phase flow in pipes , 2008 .

[26]  H. Lee,et al.  Pressure drop correlations for two-phase flow within horizontal rectangular channels with small heights , 2001 .