INFLUENCE OF THE BLADE SHROUD GAP TO THE NATURAL FREQUENCY OF THE INTERLOCKED TURBINE BLADE

An optimized structure of the integrated shroud for the circularly interlocked turbine blade is highly advantageous to increase system stiffness and decrease dynamic stress. But the working condition of the interlocked structure could affect the blade's natural frequencies greatly. The shroud gap is one of the most important design parameters for the circularly interlocked blades. To ensure a credible frequency and stress for the blade, it is necessary to choose an appropriate shroud gap to make all the adjacent shrouds pin together effectively at the rated turbine speed via the untwist effect. This paper is devoted to study the natural frequency and the coupling situation of the interlocked blades with varying shroud gap width. The commercial FEA software ABAQUS is employed to perform the simulation and the modeling results are compared with the measurement results.