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Analysis of mass transfer performance of micromixer device with varying confluence angle using CFD

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The computational fluid dynamics (CFD) study on micromixers in this paper illustrates the effect of confluence angle on mixing performance at different Reynolds numbers and flow rate ratios. The mixing performance parameters such as mixing quality and effectiveness increases with the increase in Reynolds number for all the micromixer geometries. For any value of Reynolds number, the angle of confluence is found to have a significant effect on flow behavior in the mixing channel and thus on mass transfer. The formation of vortices and the interlacing of fluid streams are identified as the favorable phenomena due to which mass transfer or mixing of fluid streams is enhanced. The mixing effectiveness is mostly observed to be high in case of unequal flow rates in the two feed/inlet channels. The optimum value of confluence angle depends of flow rate ratio. When flow rate ratio is high, T-shaped micromixer (θ = 180°) provides better performance while for other ratios, micromixers with relatively large angles of confluence are found more suitable.

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A :


c :

Concentration/mass fraction (kg/kg)

d :

Diameter (m)

D AB :

Diffusion coefficient (m2/s)

Eu :

Euler number

f :

Friction factor

l :

Channel length (m)

l m :

Mixing length (m)

L :

Total length of channels (m)

\(\Delta p\) :

Pressure drop (Pa)

Q :

Volumetric flow rate (m3/s)

R :

Flow rate ratio

Re :

Reynolds number

\(x\) :

Distance from mixing channel inlet

\(\sigma^{2}\) :

Variance of concentration

\(\alpha\) :

Mixing quality

ρ :

Density (kg/m3)

u av :

Average velocity (m/s)

u :

x-Component of velocity (m/s)

v :

y-Component of velocity (m/s)

w :

z-Component of velocity (m/s)

μ :

Viscosity (kg/m·s)

v :

Kinematic viscosity (m2/s)


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The support provided by NED University of Engineering and Technology, Karachi, Pakistan, is acknowledged.

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Correspondence to M. Shakaib.

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Fatima, U., Shakaib, M. & Memon, I. Analysis of mass transfer performance of micromixer device with varying confluence angle using CFD. Chem. Pap. 74, 1267–1279 (2020).

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