Experimental Investigation of the Heat Transfer in a Rib-Roughened Leading-Edge Cooling Channel

To investigate how different rib heights influence the heat transfer in a leading edge cooling channel, a plexiglas model was built. The model was heated using foil-heaters and the temperature was measured with thermocouples and an infrared camera. Wall static pressures were measured to get the pressure drop. The rib heights and Reynolds number were varied while the pitch between the ribs was constant. A smooth pipe was also investigated to get a reference for calculation of the enhancement factor. The investigation outcome was: • the effect of rib height on the heat transfer in the noncircular pipe becomes weaker with increased Reynolds number. • increasing the rib height by 40% cause an increase of pressure drop by a factor of 2. • the test without ribs, “smooth pipe”, resulted in a correlation for Nusselt number, Nu = 0.0232× Re^0.8 for developed turbulent flows. The tests described above helped to optimize the internal geometry of the blade leading edge and, to some extent, to expand the available heat transfer database.