Numerical Flow Analysis of The Variation of Central Axial Velocity Along The Pipe Inlet

Yıl 2018, Sayı: 2, 323 - 333, 19.08.2018

Hasan Duz

Öz

Due to no slip flow condition at the wall, the
fluid enter the pipe with a smooth velocity start to develop along the flow to
comply the zero velocity at the wall and maximum at the pipe center. After a
certain distance where the development completed, the velocity profile becomes
fully developed and no longer changes observed along the pipe flow. The region
flow where the velocity profile developes is called developing flow or inlet
flow and the region flow where the fully developed profile govern are called
fully devloped flow. Computation of the flow properties in the fully developed
region can be enabled with various empirical theories, but the complex flow
styructure in pipe inlet region still has not been solved exactly. However It
is quite important to know the flow behavior at the pipe inlet to compute the
right pumping power especially in the fluid heating and cooling short pipe flow
processes. the study performed, the steady pipe flows with Newtonian fluid were
simulated numerically at low Reynolds numbers (ranged 1000 and 25000 ) covering
the three flow regimes (laminer, transition and turbulence). High turbulence
level and smooth velocity profile were assigned to the flow at pipe inlet.
Turbulence flows were solved according to the time mean flow assumption. On the
numerical results obtained, the variation of axial central velocity along the
flow was examined for different relative roughnesses. Consequently, a numerical
correlation which define the axial velocity and fit the numerical values well
is proposed.

Anahtar Kelimeler

Entrance length, Pipe flow, Developing flow

Kaynakça

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