Abstract: The transient heat transfer characteristics of a shrouded rotating disk were investigated experimentally as the mass flow rate was changed.The disk diameter was 400 mm and its maximum rotating speed was up to 300 r/min.The disk was heated at rim to simulate the heat conduction from turbine blades.One side of disk was cooled by air and another side was adiabatic.The temperatures of cooling side and heating side were measured synchronously at different time interval.The variation of averaged Nusselt number with non dimensionalized time was obtained.It was found that the averaged Nusselt number enlarged with the increase of inlet mass flow rate,but reached its steady state value rapidly after the change of mass flow rate.