Thermo-structural investigation of gas turbine blade provided with helicoidal passages

Abstract

By having helicoidal shape for the cooling passage, it is possible to provide more surface area for cooling per unit passage length. In addition to this, by providing turbulators within the helicoidal passages, it is possible to augment an increase in heat transfer from the blade surface to the cooling fluid. Since FSI is the objective of this analysis, the blade loading corresponding to the static pressure as well as temperature field on the blades surfaces are obtained using CFD run. The output results are then used as structural boundary condition to solve FSI, using finite element method. The present work brings out thermal and structural distortion of the HP stage gas turbine blade. A parametric approach is used for varying the cooling passage geometry to optimize the cooling process. It can be concluded from FSI analysis that circular helicoidal cooling passage (4 mm Φ) of pitch 6 mm with turbulators of size e/D = 0.08 with rib thickness 0.75mm effect in improved cooling properties and in turn reduce structural deformation.