turbulence pulsating is proximal or equal to natural fre-
quency of tube, fierce vibration will take place.
2.4. Fluid-Elastic Whirling
This is characterized by tubes vibrating in an orbital or
“whirling” manner, once sufficient energy is available
for resonance to occur. This motion is produced when
the shell side flows across the tubes causes both lift and
drag movement of tubes at their natural frequencies. It
can lead to a “runaway” condition if the energy supplied
to tubes cannot be absorbed by the system damping and,
thereby, lead to failure of tubes due to flow-induced vi-
bration. Such a failure is likely to occur if the cross flow
velocity is greater than a critical velocity.
2.5. Acoustic Resonance
Acoustic resonance occurs only on the condition that
shell-side fluid is gas. When gas flows across tube bun-
dle, acoustic standing waves, which is perpendicular to
both tubes and flow direction, may come into being and
be reflected repeatedly by inner wall of heat exchanger.
Meanwhile, as gas flows across tube bundle, Karman’s
vortex street comes into being behind tubes. And when
frequency of vortex street accords with the frequency of
acoustic standing waves, the couple will come and all the
kinetic energy of flow media will be transmuted to acous-
tic pressure waves, thereby vibration and strong noise will
appear in heat exchanger.
3. Problem Definition & Objective
Flow-induced vibration analysis of a shell and tube heat
exchanger is an integral element of its thermal design. A
proper design is one that is absolutely safe against failure
of tubes due to flow induced vibration. Most sophisti-
cated thermal design software packages carry out vibra-
tion analysis as a routine ingredient of thermal design.
This is essential since it is during thermal design that the
geometry of a heat exchanger is finalized and it is this
same geometry, along with flow, physical and property
parameters, determines whether the given heat exchanger
is safe against failure of tubes due to flow-induced vibra-
tions. Flow-induced vibration is a very complex subject
and involves the interplay of several parameters, many of
which are not very well established. Although many cases
of failure of tubes due to flow-induced vibration has been
reported in the past several years, and an understanding of
the factors responsible for these failures leave much to be
desired. The literature depicts several interesting studies
on specific facets of the vibration problem; however, very
few investigations have considered the specific problems
associated with shell and tube heat exchangers.
Hence in order to provide a simple solution to above
stated problem, in this work Flow-induced Vibration
Analysis of a STHE is performed to optimize the design
Parameter. It is found that the FVA of STHE helps in
achieving optimization in design of STHE by prevention
of tube failure caused due to flow induced vibration. 5. Flow-Induced Vibration Analysis [FVA]
Table 2 shows the Flow-Induced Vibration Analysis
Results of STHE by using HTRI software.
6. Results & Discussion
From Figure 2, it is observed that the bundle shell acous-
tic frequency decreases from inlet to exit, hence the na-
ture of the plot is parabolic. Acoustic resonance is due to
gas column oscillation and is excited by phased vortex
shedding. The oscillation creates an acoustic vibration of
a standing wave type. The generated sound wave will not
affect the tube bundle unless the acoustic resonant fre- 管壳式换热器优化设计英文文献和翻译(3):http://www.751com.cn/fanyi/lunwen_2548.html