Journal of agriculture & life science (농업생명과학연구)

Institute of Agriculture & Life Science, Gyeongsang National University (경상대학교 농업생명과학연구원)
권호 표지

Numerical Predictions of Heat Transfer in the Fluidized Bed Heat Exchanger

  • Ahn, Soo-Whan (Mechanical and System Engineering, Gyeongsang National Univ.)
  • Received : 2010.03.26
  • Accepted : 2010.08.16
  • Published : 2010.08.31
⟨ Previous Next ⟩

Abstract

The numerical analysis by using CFX 11.0 commercial code was done for proper design of the heat exchanger. The present experimental studies were also conducted to investigate the effects of circulating solid particles on the characteristics of fluid flow, heat transfer and cleaning effect in the fluidized bed vertical shell and tube type heat exchanger with counterflow, at which a variety of solid particles such as glass ($3mm{\Phi}$), aluminum ($2{\sim}3mm{\Phi}$), steel ($2{\sim}2.5mm{\Phi}$), copper ($2.5mm{\Phi}$) and sand ($2{\sim}4mm{\Phi}$) were used in the fluidized bed with a smooth tube. Seven different solid particles have the same volume, and the effects of various parameters such as water flow rates, particle diameter, materials and geometry were investigated. The present experimental and numerical results showed that the flow velocity range for collision of particles to the tube wall was higher with heavier density solid particles, and the increase in heat transfer was in the order of sand, copper, steel, aluminum, and glass. This behavior might be attributed to the parameters such as surface roughness or particle heat capacity.

Keywords

Acknowledgement

Supported by : Gyeongsang National University

References

  1. Bird, R. B., W. E. Stewart, and E. Lightfoot. 1960. Transport Phenomena. John Wiley and Sons Inc. NewJersey, USA.
  2. Brea, F. M. and W. Hamilton. 1971. Heat transfer in liquid fluidized beds with a concentric heater. Trans. of the Inst. of Chem. Eng. 49: 196-203.
  3. Garic-Grulovic, R. V., Z. B. Grbavcic, and Z. L. Arsenijevic. 2004. Heat transfer and flow pattern in vertical liquid-solid flow. Powder Technology. 145: 163-171. https://doi.org/10.1016/j.powtec.2004.07.006
  4. Haid, M., V. Martin, and H. Muller-Steinhagen. 1994. Heat transfer to liquid- solid fluidized beds. Chem. Eng. and Proc.33: 211-225. https://doi.org/10.1016/0255-2701(94)01003-X
  5. Kim, C. K., S. W. Ahn, and B. G. Lee. 1994. Turbulence structures of flow in concentric annuli with rough outer wall, Trans. KSME. 18: 2443-2453.
  6. Kim, N. H. and Lee, Y. P. 2001. Hydrodynamic and heat transfer characteristics of glass bead-water flow in a vertical tube. Desalination. 133: 233-243. https://doi.org/10.1016/S0011-9164(01)00104-7
  7. Klaren, D. G. 1975. Development of a vertical flash evaporator. Ph. D. Thesis. Delft University of Technology.
  8. Klaren, D. G. 2000. Self cleaning heat exchangers, in: H. Muller-Steinhagen (Ed.). Handbook heat exchanger fouling: mitigation and cleaning technologies. Rugby Inst. of Chem. Eng. 186-199.
  9. Kline S. J. and F. A. McClintock. 1953. Describing uncertainties in single sample experiments. Mech. Eng. Am. Soc. Mech. Eng. 75: 3-8.
  10. Kwauk, M. 1992. Fluidization: Idealized and Bubbleless, with Applications. Beijing, Science Press.
  11. Lian, W. G., S. Zhang, J. X. Zhu, Y. Jin, Z. Q. Yu, and Z. W. Wang. 1997. Flow characteristics of the liquid-solid circulating fluidized bed. Powder Technology. 90: 95-102. https://doi.org/10.1016/S0032-5910(96)03198-1
  12. Menter, F. R. 1993. Zonal two equation ${\kappa}-{\omega}$ turbulence models for aerodynamic flows. AIAA Paper. 98-0522.
  13. Rautenbach, R. and T. Katz. 1996. Survey of long time behavior and costs of industrial fluidized bed heat exchangers. Desalination. 108: 335-344.
  14. Richardson, J. F., M. N. Romani, and K. J. Shakiri. 1976. Heat transfer from immersed surfaces in liquid fluidized beds. Chem. Eng. Sci. 31: 619-624. https://doi.org/10.1016/0009-2509(76)87002-9
  15. Wilcox, D. 1986. Turbulence Modeling for CFD. DCW Industries Inc. La Canada, CA.
  16. Ziegler, E. N., and W. T. Brazelton. 1964. Mechanisms of heat transfer to a fixed surface in a fluidized bed. Ind. Eng. Chem. Fundamentals. 3: 324-328. https://doi.org/10.1021/i160012a008