The Effects of Inlet Turbulence on the Development of Fluid Flow and Heat Transfer in a Helically Coiled Pipe

Abstract In this paper, the effects of inlet turbulence level on the development of three-dimensional turbulent flow and heat transfer in the entrance region of a helically coiled pipe are investigated by means of a fully elliptic numerical study. The k – e standard two-equation turbulence model is used to simulate turbulent flow and heat transfer, which are assumed to develop from the inlet to the outlet simultaneously. Constant wall temperature and uniform inlet conditions are applied. The governing equations are solved by a Control-Volume Finite Element Method with an unstructured nonuniform grid system. Numerical results presented in this paper cover a Reynolds number range of 10 4 –10 5 , a Prandtl number range of 0.02–100, and an inlet turbulence intensity range of 2–40%. The development of the main velocity field, the secondary velocity field, the temperature field, bulk turbulent kinetic energy, the average friction factor, and average Nusselt numbers are discussed. It is found that bulk turbulent kinetic energy far from the entrance is not affected by the inlet turbulence level. Significant effects of the inlet turbulence level on the development of the friction factor and Nusselt number occur within a short axial distance from the entrance only.

[1]  V. A. Mikaila,et al.  Local heat transfer in coiled tubes at high heat fluxes. I, Experimental unit, technique and results of preliminary experiments , 1990 .

[2]  Cheng-Xian Lin,et al.  Developing Turbulent Convective Heat Transfer in Helical Pipes , 1996, Heat Transfer: Volume 2 — Heat Transfer in Turbulent Flows; Fundamentals of Convection Heat Transfer; Fundamentals of Natural Convection in Laminar and Turbulent Flows; Natural Circulation.

[3]  J. Humphrey,et al.  Experimental Observations of Flow Instability in a Helical Coil (Data Bank Contribution) , 1993 .

[4]  B. K. Rao.  Turbulent heat transfer to power-law fluids in helical passages , 1994 .

[5]  B. Launder,et al.  Mathematical Models of turbulence , 1972 .

[6]  B. K. Rao.  Turbulent Heat Transfer to Viscoelastic Fluids in Helical Passages , 1993 .

[7]  D. Spalding,et al.  A calculation procedure for heat, mass and momentum transfer in three-dimensional parabolic flows , 1972 .

[8]  S. Das.  Water flow through helical coils in turbulent condition , 1993 .

[9]  J. P. V. Doormaal,et al.  ENHANCEMENTS OF THE SIMPLE METHOD FOR PREDICTING INCOMPRESSIBLE FLUID FLOWS , 1984 .

[10]  G. Raithby,et al.  A multigrid method based on the additive correction strategy , 1986 .

[11]  D. B. Spalding,et al.  Heat transfer—soviet research , 1969 .

[12]  Wataru Nakayama,et al.  Study of forced convective heat transfer in curved pipes (2nd report, turbulent region) , 1967 .

[13]  Y. R. Mayhew,et al.  Heat transfer and pressure loss in helically coiled tubes with turbulent flow , 1964 .

[14]  Nakayama Wataru,et al.  Study on forced convective heat transfer in curved pipes: (1st report, laminar region) , 1965 .

[15]  B. Launder,et al.  The numerical computation of turbulent flows , 1990 .

[16]  M. A. Ebadian,et al.  Turbulent forced convection in a helicoidal pipe with substantial pitch , 1996 .

[17]  Shijie Liu.  Laminar flow and heat transfer in helical pipes with finite pitch , 1992 .

[18]  H. Itō,et al.  Friction Factors for Turbulent Flow in Curved Pipes , 1959 .

[19]  D. B. Spalding,et al.  Prediction of laminar flow and heat transfer in helically coiled pipes , 1974, Journal of Fluid Mechanics.

[20]  B. R. Baliga,et al.  A CONTROL VOLUME FINITE-ELEMENT METHOD FOR TWO-DIMENSIONAL FLUID FLOW AND HEAT TRANSFER , 1983 .

[21]  Dudley Brian Spalding,et al.  Prediction of turbulent flow in curved pipes , 1975, Journal of Fluid Mechanics.