High Rotation Number Effect on Heat Transfer in a Triangular Channel With 45 deg, Inverted 45 deg, and 90 deg Ribs

Heat transfer and pressure drop have been experimentally investigated in an equilateral triangular channel $(Dh=1.83cm)$⁠, which can be used to simulate the internal cooling passage near the leading edge of a gas turbine blade. Three different rib configurations (45 deg, inverted 45 deg, and 90 deg) were tested at four different Reynolds numbers (10,000–40,000), each with five different rotational speeds (0–400 rpm). The rib pitch-to-height $(P/e)$ ratio is 8 and the height-to-hydraulic diameter $(e/Dh)$ ratio is 0.087 for every rib configuration. The rotation number and buoyancy parameter achieved in this study were 0–0.58 and 0–2.3, respectively. Both the rotation number and buoyancy parameter have been correlated with predict the rotational heat transfer in the ribbed equilateral triangular channel. For the stationary condition, staggered 45 deg angled ribs show the highest heat transfer enhancement. However, staggered 45 deg angled ribs and 90 deg ribs have the higher comparable heat transfer enhancement at rotating condition near the blade leading edge region.