Abstract: The flow and heat transfer of n-decane under supercritical pressure were studied ex-perimentally using an electrically heated tube according to the conditions in a regenerative cooling scramjet.The fuel was heated in a 1.5 mm inner diameter tube of 1Cr18Ni9Ti,and the total length of the tube was 1300mm.The fuel mass fluxes were 0.93g/s,1.24g/s and 1.86g/s in the three runs respectively.Seventeen type K and 0.3mm outer diameter thermocouples were spot welded directly to the outer surface of the tube to measure outer wall temperatures.The pressure of n-decane was varied from 4.0 to 4.3MPa,and the fuel temperature was varied from 335 to 870K in the experiments.The Reynolds number ranged from about 800 to 70000 and Prandtl number ranged from about 0 to 1 5 .Blank tube heating experiments were used to calibrate the tube thermal loss rate at different temperatures.At the positions within 0~0.2m and 1.2~1.3m along tube,inner wall heat flux was smaller due to additional thermal loss by the joint metal blocks near the inlet and outlet.Especially within 1 .2~1 .3m which was near the outlet,the tube temperatures were much higher than those within 0~0.2m near the inlet,so the inner wall heat flux drops steeply down.In the tests the data within 0.2~1.2m along tube were chosen for stud-y.The heat transfer correlations of n-decane in laminar,transition and turbulent flow regions were determined using the method of least squares curve fitting.The calculated outer wall tem-peratures were compared with experimental values,which confirmed the validity of the presented correlations .