Laminar-to-turbulent flow transition in microchannels

Some experimental results on heat transfer and pressure drop through microchannels evidenced that the conventional theory, validated for large-size channels, has to be revised for channels having a hydraulic diameter smaller than I mm. Also, the transition from the laminar to the turbulent regime usually takes place at Reynolds numbers lower than those expected. This is considered a confirmation of the disagreement with the classical theory. This paper shows how many experimental results on the laminar-to-turbulent transition in microchannels can be explained by using the "Obot-Jones model," obtained by means of the conventional theory for large-size channels.