Optimal Design of Tube Banks in Crossflow Using Entropy Generation Minimization Method

Abstract

An entropy generation minimization method is applied as a unique measure to study the thermodynamic losses caused by heat transfer and pressure drop for a fluid in cross flow with tube banks. The use of entropy generation minimization allows the combined effect of heat transfer and pressure drop to be assessed through simultaneous interaction with the tube bank. A general dimensionless expression for the entropy generation rate is obtained by considering a control volume around a tube bank and applying conservation equations for mass and energy with entropy balance. Analytical/empirical correlations for heat transfer coefficients and friction factors are used, where the characteristic length is used as the diameter of the tubes and reference velocity used in Reynolds number and pressure drop is based on the minimum free area available for the fluid flow. Both inline and staggered arrangements are studied and their relative performance is compared for the same thermal and hydraulic conditions. A parametric study is also performed to show the effects of different design variables on the overall performance of tube banks. It is shown that all relevant design parameters for tube banks, including geometric parameters and flow conditions, can be simultaneously optimized.

Optimization of heat exchangers of refrigeration machines by entropy generation minimization method

“…Такая оптимизация возможна только с применением термодинамического анализа методом минимизации производства энтропии. Работы [12][13][14] принадлежат группе исследователей лаборатории микроэлектро-ники Университета Ватерлоо (Канада). В работах рассмотрена оптимизация компактных оребренных микроканальных охладителей методом минимиза-ции производства энтропии.…”

Modern Fluid Dynamics

“…Minimization of entropy generation as a design tool to determine best device geometry and operation, especially for heat exchangers, has been established for macro-scale configurations (see Bejan 1996Bejan , 2002Sahin 1998Sahin , 2000Mahmud & Fraser 2003;Mansour et al 2006;Khan et al 2007;Ko & Wu 2009; among others). However, fluid flow in microchannels exhibits dominant features often non-existing or less influential in macrochannels, e.g., wall-slip velocities for some gases, entrance effects because of the short conduit length, significant surface roughness in relation to microchannel height (or hydraulic diameter), etc.…”

Computational Fluid Dynamics and Heat Transfer Analysis for a Novel Heat Exchanger

“…The question here is, can the tubes in shell be oriented such that the heat transfer between the two fluids is enhanced, while the pressure drop across the heat exchanger is still reasonable. Tube arrangement optimization in shell-tube heat exchangers has been studied extensively by employing various methods [7][8][9][10][11][12][13]. These investigators have shown that the spacing, orientation, and the arrangement of tubes in the shell have profound influence on the thermal performance.…”