A. M. BAGABIR ET AL.

Open Access JAMP

4% - 38% depending on Reynolds number. It is found

that the staggered inclined ribs produce similar thermal

profile as inline orientation but with higher friction factor.

The staggered orientation lowers the thermal perfor-

mance of 45˚ V-shape and reduces the friction factor. On

the contrary, the staggered 90˚ transverse rib reveals

thermal enhancement factor similar to inclined and

V-shaped ribs for Reynolds number equal or higher than

2 × 104. For Reynolds number of 104, the inline 45˚ rib

reveals the optimum thermal enhancement factor.

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Nomenclature

D: Hydraulic diameter of channel width (m)

e: Rib width (m)

f: Friction factor for a ribbed channel

f0: Friction factor for a smooth channel

h: Rib height (m) or heat transfer coefficient

H: Channel height ( m)

k: Thermal conductivity (W/mK)

Nu: Nusselt nu mber of a ribbed channel

Nu0: Nusselt number of a smooth channel

p: static pressure (pa) or rib pitch spacing (m)

Pr: Prandtl number

q: Heat flux (W/m2)

Re: Reynol ds number

TB: Bulk tem pe rature of flow (K)

TS: Surface temperature (K)

Tw: Wall temperature (K)

TEF: Thermal enhancement factor

u: Velocity (m/s)

Um: Bulk velocity (m/s)

W: Channel wi dth (m)

ρ

: Density (kg/m3)