Abstract: The experimental investigation on liguid cooling mechanism was carried out with water through an even-heated adiabatic straight pipe.The flow pattern,the heat transfer coefficient along full-flow-path,and the correlation between them,have been studied.In order to imitate the actual working conditions of the cooling passage of turbine vane,the heat transfer flux,the coolant inlet parameters,and the pipe angle are changeable.Some empirical formulas for come-to-saturated point Z B and come-annular point Z N have been derived and several useful conclusions have been drawn for engineering application.