AERO STRUCTURE INTERACTION FOR MECHANICAL INTEGRATION OF LACED LP COMPRESSOR BLADES IN A GAS ENGINE ROTOR

Aero-structure interaction during turbomachinery blade design has become an important area of research due to its critical applications in aero engines and land based gas turbines. Studies reveal that a certain mistuning leads to stress build up through mode localization under operating conditions. This paper deals with comparative case studies of aero-structure interaction for free standing and various laced LP blade configurations of a gas turbine. The lacing wire provides better structural integrity as it is more aerodynamic and feasible when compared to cases of free standing blades without lacing wires. Hence calling for the optimum positioning checks at (1)/(th)(4), (1)/(2) , (3)/(th)(4) and combined positioning at (1)/(4)th and (3)/(th)(4) along the length of LP mpressor blades. The lacing wire of both circular and elliptical cross sections are considered for comparative study for better aerodynamic performance. Assuming 100% fixity at blade root, the study involves critical parametric evaluations involved in achieving mechanical integrity in airfoil design and blade platform design. Mechanical integrity involves stress checks, frequency margins, Campbell Diagram, gross yield stress, Stress Stiffening and Spin Softening of blades and so on, for design and off-design conditions for a given stage efficiency of 93% in an ideal LP compressor of a gas turbine engine.