In this paper

an experiment is conducted to investigate the effects of oscillation on transient and time average heat transfer characteristics for fully developed turbulent flow in a uniformly heated helical coiled tube. The phase lag of transient coefficient of local heat transfer relative to the phase feature of flow rate oscillations is also studied. The experimental range of parameters is as follows: Re=25000～125000

oscillations frequency f=0.05～0.003

which corresponds to the thermal hydrodynamic oscillations encountered in a helical coiled tube boiling channel. A correlation for predicting the time-averaged heat transfer coefficient of single-phase turbulent flow under unsteady or oscillatory condition is proposed. The secondary flow mechanisms and the effects of interaction between the flow rate oscillation and secondary flow are analyzed on the basis of experimented data. Some new phenomena are observed and explained.