LAMINAR FRICTION FACTOR IN MICROSCALE DUCTS OF IRREGULAR CROSS-SECTION

An analysis was performed to develop a method by which the friction fa ctor could be determined for microscale channels of the type utilized in micro heat pipes. Using a combination of analytical techniques and numerical integration methods, an expression governing laminar, fully developed fluid flow occurring in very small ducts of irregular cross section was developed and solved. By changing the functions that descr ibe the boundaries, the friction factor and Reynolds number product wa s readily obtained for a number of different types of cross sections. Using this method, the friction factor and Reynolds number product occ urring in a micro heat pipe where the cross section varies from the ev aporator to the condenser was solved without the need to reformulate t he problem to determine the analytical solution, or reestablish the gr id mesh to find numerical results for a given location along the axial direction.