Page 21 - 2019

Ph.D.
(Engineering & Technology)
NUMERICAL SIMULATION OF FLUID FLOW IN
TUBES WITH INSERTS

Ph.D. Scholar : Patel Shailesh Kantilal
Research Supervisor : Dr. Kedar A. Pathak, Co. Guide : Dr. L. N. Patel

Regi. No.: 11146051010
Abstract :
Effective utilization, saving, and revival of heat are critical engineering problems for the
process industry. The fiscal design and operation of process plants are often governed by
the efficient usage of heat. The simplest type of heat exchanger and widely used in
industry i.e. double pipe heat exchanger (DPHE) is chosen for numerical investigation
with various inserts. Inserts or artificial roughness on the heat transferring surface in the
form of wires, integral ribs or twisted tape inserts of various shapes and in different
arrangements has been used in tubes and annular ducts to enhance the heat transfer
coefficient. In case of solid roughness elements, the heat transfer enhancement is
associated with significant increase in pressure drop also. Perforated elements have
been shown to reduce hot zones develop in the wake of the solid roughness elements
effects associated with the solid ribs.
The research objective of the present work is to carry out numerical investigation of heat
transfer and friction for the flow of fluid in tubes with perforated inserts. The effect of the
relative roughness pitch and the perforation of the insert has been studied. The
Perforated inserts generate the swirl flow and near wall turbulence will increase heat
transfer coefficient with less pressure loss. Numerical investigation carried out to study
the swirl flow behavior and the laminar convective heat transfer numerically in a circular
tube with inserts i.e. groove and helical perforated baffle on inner pipe of DPHE. The fluid
flow and thermal fields are simulated computationally in an effort to characterize their
structure. The local wall shear stress and heat flux or temperature distributions are
predicted along with the average friction factors and Nusselt numbers for different flow
Reynolds numbers, artificial roughness i.e. insert geometry, and wall thermal boundary
conditions.
In circumstances when the well recognized classical methods for function determination
cannot provide the required degree of accurateness or become inapplicable, the inverse
heat transfer problem (IHTP) technique can be used. The Conjugate Gradient Method
using adjoint problem for functional estimation is one of the various techniques by which
the function estimation is accomplished iteratively. The IHTP is the technique which is
able to estimate variables inside the complex system by knowing just surface

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