Laminar forced convection flow past an in-line elliptical cylinder array with inclination

Flow past a cylinder array with various configurations has

wide range of practical engineering applications, such as in heat

exchangers, boilers, condensers, and energy storage systems. The

thermal performance of these systems is important in meeting the

efficiency standards with low cost and environmental impact. On

The physical model consists of flow around an in-line five elliptical

cylinder array. The inclination of the elliptical

cylinders increases with the number of the cylinder in the row: the

first cylinder has 0o inclination while the last has 90o inclination. The

fluid y p flow and heat transfer are solved as a transient problem to

the other hand, flow past a cylinder array has been attracting the

attention of many academic researchers because it contains

interesting fluid dynamics phenomena such as flow instability,

free-shear layer, flow separations, and vortex shedding, and many

others. the Reynolds number is the most important parameter that

affects the heat exchange between the cylinders and flow.

Obviously, increasing the Reynolds number increases the Nusselt

capture an expected vortex shedding street phenomenon. The

working fluid is air, Pr=0.71. Since the cylinders are tightly packed, it

is assumed that no flow or heat transfer is taking place in cross

direction along the lateral boundaries. The length of the cylinders are

typically long for heat exchangers, and therefore, the flow field and

heat transfer are considered to be two-dimensional, consisting of a

single row. Therefore, researchers are concentrating their efforts

on the heat transfer enhancement from the cylinders through the

modification of the flow pattern. Destroying the hydrodynamics

boundary layer and creating several separation and reattachment

points at the cylinders’ surface are the objectives of the flow

modification technique. In this regards, researchers examined

a and b, respectively. The inclination angle of the cylinders is θ, and

Fig. 1 depicts an elliptical cylinder with the important geometrical

parameters. various techniques, such as using an array of delta-winglet vortex

generator for in-line tubes, and this technique provided an overall

heat transfer enhancement of about 32%, but with a similar

pressure drop penalty.