Numerical Simulation on the Last-Stage Low-Pressure Turbine with and without Lacing Wire

Yone, Thearith (2023) Numerical Simulation on the Last-Stage Low-Pressure Turbine with and without Lacing Wire. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Steam turbine engines are essential devices in power generation and other industrial applications, converting steam’s thermal energy into mechanical work efficiently. With ongoing research and technological advancements, steam turbine engines continue to evolve, contributing to the global quest for cleaner and more sustainable energy solutions by operating on the principle of converting the kinetic energy of steam into mechanical energy, which is produced by heating water to its boiling point, generating high-pressure steam that flows into the turbine. The wide range of speed, loading, and backpressure are three notable causes that ordinarily appear throughout the steam turbine works. Depending on these influences, the steam turbine’s last LP stage easily achieves failure because of the vibrations that make the blade operate in an unstable manner. The variation of mass flow rate may be a crucial factor in causing the rotor blade to rotate under inconstant conditions. To reduce the failure of the turbine where the lac�ing wire mounts between adjoining rotor blades. The last stage of the LP turbine works in complex flow with various mass flow rates for high, medium, and low conditions, which are observed in steady-state flow phenomena and rotor-stator interaction. The primary objective of this study is to investigate the characteristics of the performance parameters in the last stage LP steam turbine, which explores the Computational Fluid Dynamics (3D CFD) and structure Finite Element Analysis (FEA) for the stator-rotor interaction with the varying load mass flow rate (80%, 100%, and 120%) of two models for the rotor blade that rotates with and without lacing wire. Three-dimensional numerical simulations of compressible steady flow were implemented using ANSYS Fluent 19.2. The frame motion approach with mesh interface periodicity and the k-omega SST turbulence model are applied to simulate compressible steady-state stator-rotor interaction. To study the stresses along the blade, a Finite Element Analysis (FEA) method is carried out by AN�SYS Mechanical 19.2: The coupling approach is used to allow the flow data to be imported from the CFD model to the FEA model. Under three distinct loads, the outcomes of the numerical simulation for the two models are contrasted. The torque is maximum during high load conditions and design conditions, while the last stage blade’s efficiency is lowest under low load conditions (80%), according to the energy conversion efficiency. Moreover, the maximum stress on the blade with lacing wire is higher than the model without lacing, but the blade deformation for the model with lacing wire is smaller than the model without lacing wire.

Item Type: Thesis (Masters)
Uncontrolled Keywords: 3D CFD, FEA, Last stage LP steam turbine, Lacing wire, stator-rotor interaction.
Subjects: T Technology > TJ Mechanical engineering and machinery > TJ164 Power plants--Design and construction
T Technology > TJ Mechanical engineering and machinery > TJ266 Turbines. Turbomachines (General)
Divisions: Faculty of Industrial Technology and Systems Engineering (INDSYS) > Mechanical Engineering > 21101-(S2) Master Thesis
Depositing User: Thearith Yone
Date Deposited: 11 Aug 2023 01:12
Last Modified: 11 Aug 2023 01:12

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