Effects of Free Stream Turbulence and Unsteady Wake on Convective Heat Transfer Around a Radially Rotating Cylinder

摘要

Experiments were conducted to investigate the effects of free stream turbulence and unsteady wake on convective heat transfer of axial air flow on a radially rotating cylinder. In the experiment, one used wake generator for simulating turbine stator, and rotating circular cylinder for turbine blade. Furthermore, one utilized cold air-hot cylinder in the experiment instead of hot air-cold blade in a real engine. The bakelite test cylinder was pasted with a heater made of 0.03 mm thin film of stainless steel. The maximum air stream velocity was 20 m/s with the corresponding Reynolds number (Re=U_mD/v) of 1.2 X 10~5 that was high enough to simulate the real turbine blade of Re ≈10~5. When the blade rotates, additional centrifugal and Coriolis forces appear in the heated fluid near the blade. With the effect of rotation and high turbulence intensity, the cylinder surface temperature was measured and analyzed for determining the heat transfer coefficient.