The Challenge to Measure Single-phase Convective Heat Transfer Coefficients in Microchannels

Abstract

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Compressible Fanno flows in micro-channels: An enhanced quasi-2D numerical model for turbulent flows

“…The experimental study of compressible micro-flows poses a number of problems [18] primarily due to the difficulty in having a strict control over the channel dimension and wall relative roughness at such small scales. Moreover, still due to the scale of the problem, measurements are particularly error prone.…”

Review of Optical Thermometry Techniques for Flows at the Microscale towards Their Applicability to Gas Microflows

“…Most of these applications require a control of the heat transfer and temperature distributions inside the gas flow. In addition, the determination of convective heat transfer coefficients for flows in microchannels is directly related to the knowledge of temperature distribution in these channels [20]. The knowledge and mastering of temperature distributions at an experimental level is not only of engineering applications interest, but it is also of fundamental importance for validating the theoretical models which are commonly used to predict fluid flow and heat transfer at the microscale [21][22][23].…”

“…With the arrival of microfluidics, the first experimental approach towards the measurement of temperature distributions at the microscale was to scale down the existing macroscale measurement techniques [20]. However, many of these techniques were not viable at microscale, mainly due to their high intrusiveness leading to flow perturbations.…”

Research methods in the study of heat transfer coefficient during flow in minichannels

“…However the method is not devoid of restrictions regarding the measurements in small diameter channels. In many practical cases the experimental measurements of basic thermal parameters in minichannels are troublesome or even impossible [6]. In particular, the problem is related to the temperature or heat flux measurement difficulties inside small diameter channels, especially of complex geometries.…”