On The Uncertainty Of The Measurements Of
Friction Factor In Trapezoidal Microchannels, A Statistical Analysis
Author(s)
G. Bizzarri
Abstract
On the uncertainty of the measurements of
friction factor in trapezoidal microchannels,
a statistical analysis
G. Bizzarri
Dipartimento di Architettura, Università di Ferrara, Italy
Abstract
A large body of literature exists on fluid flow in microchannels, and several
studies are specifically concerned with evaluation of the friction factor. Given
the shape of the cross section, the value of the friction factor can be estimated
from laminar pipe flow theory. However, a number of laboratory investigations
found the experimental value of the friction factor to differ significantly from
that predicted by the classical theory. To explain this discrepancy, several
approaches are possible. In this paper, a stochastic approach is adopted to study
laminar flow in trapezoidal microchannels. The friction factor is evaluated as a
function of random variables: geometrical parameters characterizing the cross
section, pipe hydraulic diameter, flow rate, and pressure drop over a given
length; an effective (true) value of the friction factor is calculated assuming that
the former variables fluctuate in space and time in accordance with sinusoidal
functions. The effective friction factor is then compared with its apparent value
computed from the mean (measured) quantities; a numerical example is also
provided. Results show that, even though the difference between the effective
and apparent value is often negligible, the statistical theory can nevertheless
provide a possible explanation of the deviations between the experimental values
of the friction factor reported in literature and those predicted from the
conventional theory.
Keywords: friction factor, trapezoidal microchannels, statistical analysis.
1 Introduction
The knowledge of the flow behaviour at the microscale is an important issue in
many engineering applications. In particular, to get a reliable prediction of
friction factor is helpful in the design of microfluidic devices. This is for the
Keywords
friction factor, trapezoidal microchannels, statistical analysis.
Related Book
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