한국전산유체공학회지 (Journal of computational fluids engineering)

한국전산유체공학회 (Korean Society of Computational Fluids Engineering)
권호 표지

균일입구유속 조건의 나선관 입구영역의 층류 유동

LAMINAR FLOW IN THE ENTRANCE REGION OF HELICAL TUBES FOR UNIFORM INLET VELOCITY CONDITIONS

  • 발행 : 2008.03.31
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초록

A numerical study for laminar flow in the entrance region of helical tubes for uniform inlet velocity conditions is carried out by means of the finite volume method to investigate the effects of Reynolds number, pitch and curvature ratio on the flow development. This results cover a curvature ratio range of 1/10$\sim$1/320, a pitch range of 0.0$\sim$3.2, and a Reynolds number range of 125$\sim$2000. It has been found that the curvature ratio does significantly effect on the angle of flow development, but the pitch and Reynolds number do not. The characteristic angle $\phi_c(=\phi/\sqrt{\delta})$, or the non-dimensional length $\overline{l}(=l\sqrt{\delta}cos(atan\lambda)/d)$ can be used to represent the flow development for uniform inlet velocity conditions. In uniform inlet velocity conditions, the growth of boundary layer delays the flow development attributed to centrifugal force, and in which conditions the amplitude of flow oscillations is smaller than that in parabolic inlet velocity conditions. If the pitch increases or if the curvature ratio or Reynolds number decreases, the minimum friction factor and the fully developed average friction factor normalized with the friction factor of a straight tube and the flow oscillations decrease.

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참고문헌

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