Page 21 - 2018

Ph.D.
(Engineering & Technology)
OPTIMIZATION OF HEAT RECOVERY IN
THERMAL POWER PLANT USING CFD

Ph.D. Scholar : Patel Dilipkumar Shankarlal
Research Supervisor : Dr. Kedar A. Pathak

Regi. No.: 11146051008
Abstract :
Thermal power plant is one of the major contributors in using fossil fuel for the
production of electricity. The other key industrial energy users devote significant
proportions of their fossil fuel consumption to steam production. Since industrial
systems are very diverse, but often have major steam systems in common, it makes a
useful target for energy efficiency measures. The amount of heat released from the
combustion of fossil fuel is transferred to the working medium in the plant through the
heat exchangers at various stages in the plant cycle. Hence a focal point for heat
exchanger research is the optimum heat recovery which ultimately improves the
performance of heat exchanger and producing more cost effective thermal systems.

Regardless of being several flow arrangements, the hot and cold fluids in any heat
exchanger are normally separated by solid material like a pipe wall where heat exchange
takes place. Therefore, the heat transfer rate is equivalently be obtained by estimating the
heat flux through the solid/ fluid boundaries. The accurate estimation of heat transfer
rate at the thermal boundary in the heat exchanger leads to the optimum design of the
equipment under the limitations of shape, size and material. Classical methods for the
heat exchanger calculation become inappropriate as constant physical properties were
used. In such situations inverse analysis for solving heat transfer problems to obtain
accurate prediction of thermophysical quantities is one of the efficient methods.

The iterative technique for function estimation by means of Conjugate Gradient Method
with adjoint problem is proposed to estimate the unknown time varying functional form
of the boundary heat flux. The boundary conditions are customized to resemble to the
real life problem of interest. The numerical solution to the two-dimensional heat
conduction problem and convection problem is obtained using inverse heat transfer
concept. In this optimization problem a squared residue functional is minimized with the
conjugate gradient method. A sensitivity problem is solved to determine the step size in
the direction of descent, and an adjoint problem is solved to determine the gradient of the
functional. Tikhonov regularization approach is second-hand to promote smoothness to
the solution of problem.

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