Friction loss factors of hydraulically smooth pipes have been calculated by using several different turbulent models.Through comparison of calculated results with Nikuradse's test results

it was found that the result from Spalart-Allmaras turbulent model tallies with Nikuradse's test result much better than other turbulent models

the maximal error of calculated results under five different Reynolds numbers all was 1.65%.At the same time

the study also indicates that the flow resistance in a pipeline is mainly determined by the velocity distribution near the wall surface regardless the liquid flow to be laminar or turbulent flow in a round pipe.