Numerical Modeling of Transient Turbulent Gas Flow in a Pipe Following a Rupture


Department of Mechanical Engineering,Sharif University of Technology


The transient
ow of a compressible gas generated in a pipeline after an accidental rupture
is studied numerically. The numerical simulation is performed by solving the conservation equations of an
axisymmetric, transient, viscous, subsonic
ow in a circular pipe including the breakpoint. The numerical
technique is a combined nite element- nite volume method applied on the unstructured grid. A modified
 ???? " model with a two-layer equation for the near wall region and compressibility correction is used to
predict the turbulent viscosity. The results show that, for example, after a time period of 0.16 seconds,
the pressure at a distance of 61.5 m upstream of the breakpoint reduces about 8%, while this value for
the downstream pressure located at the same distance from the rupture is about 14% at the same time.
Also, the mass
ow rate released from the rupture point will reach 2.4 times its initial value and become
constant when the sonic condition occurs at this point after 0.16 seconds. Also, the average pressure of
the rupture reduced to 60% of its initial value and remained constant at the same time and under the
same condition. The results are compared with available experimental and numerical studies for steady
compressible pipe