Effect of entrance condition on frictional losses and transition to turbulence

Satish Kandlikar
Levi Campbell

Proceedings at the international mechanical engineering conference and exposition, November 17-21, 2002. The complete proceedings can be found at www.asme.org . Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.


In studying the fluid flow and heat transfer in microchannels, various claims have been made regarding transition at Reynolds numbers significantly below 2300. As a first step in identifying the reasons for such early transition, the effect of entrance geometry on the pressure drop and transition to turbulence is studied experimentally in a conventional channel of 1.9 cm inner diameter. Four types of entrance conditions have been studied with flow of oil in a closed loop. The experimental results show the effect of entrance conditions on local friction factor, hydrodynamic developing length, and transition Reynolds number. The study will be extended to microchannels in the future.