Dynamic Analysis Of Turbine Blades In Contact
Sukhwal, Nitin
Dynamic Analysis Of Turbine Blades In Contact by Nitin Sukhwal - IIT Jodhpur Department of Mechanical Engineering 2020 - xviii,55p. HB
Turbojets and turbofans are air breathing jet engines that are widely used in aircraft propulsion. Each fan blade carries a load equivalent of nine double-decker buses and swallows the volume of a squash court every second. Cruise missiles, supersonic figh-ters, and hovercraft are some examples of high speed transportation and combating machines, which are driven by turbomachines. The major problem associated with tur-bomachines is its failures in-service results in high costs for repair, safety risks and losses of non-operational income. Thus, the reliability of these blades is very important for the successful operation of the turbo-machine. The frequently identified cause of blade failure is vibration in turbine blades. Resonance is a severe problem, which causes turbine blade failure, and this condition occurs when natural frequency of the rotating body is equal to the rotational speed of the body. Since resonant condition cannot be avoided always, a possible way to avoid the risk of blade failure is by incorporating some kind of friction damping created due to the loading between contacting surfaces at the tip of the blades. This mechanism re-sults in physically limiting the vibrational amplitude on the blade tip. This is achieved by leaving a small gap between the shrouds of adjacent blades. The main objective of this study is to perform the dynamic analysis of the turbine blades in contact. This has nonlinear response problem has been analyzed by varying the gap between the shrouded tip of turbine blades. For this study, a turbine disc-blade assembly model has been developed in SOLIDWORKS® followed by performing modal analysis in AN-SYS® workbench, and the blade response is evaluated in time domain using Newmark-beta method. The response calculations have been performed for different values of spring and damping constants to identify their effect on the blade response. From these response curves, the relation between vibration amplitude and gap between the shrouds has been identified.
Turbine Blades
MTech Theses
Department of Mechanical Engineering
621.431 5 / Su46D
Dynamic Analysis Of Turbine Blades In Contact by Nitin Sukhwal - IIT Jodhpur Department of Mechanical Engineering 2020 - xviii,55p. HB
Turbojets and turbofans are air breathing jet engines that are widely used in aircraft propulsion. Each fan blade carries a load equivalent of nine double-decker buses and swallows the volume of a squash court every second. Cruise missiles, supersonic figh-ters, and hovercraft are some examples of high speed transportation and combating machines, which are driven by turbomachines. The major problem associated with tur-bomachines is its failures in-service results in high costs for repair, safety risks and losses of non-operational income. Thus, the reliability of these blades is very important for the successful operation of the turbo-machine. The frequently identified cause of blade failure is vibration in turbine blades. Resonance is a severe problem, which causes turbine blade failure, and this condition occurs when natural frequency of the rotating body is equal to the rotational speed of the body. Since resonant condition cannot be avoided always, a possible way to avoid the risk of blade failure is by incorporating some kind of friction damping created due to the loading between contacting surfaces at the tip of the blades. This mechanism re-sults in physically limiting the vibrational amplitude on the blade tip. This is achieved by leaving a small gap between the shrouds of adjacent blades. The main objective of this study is to perform the dynamic analysis of the turbine blades in contact. This has nonlinear response problem has been analyzed by varying the gap between the shrouded tip of turbine blades. For this study, a turbine disc-blade assembly model has been developed in SOLIDWORKS® followed by performing modal analysis in AN-SYS® workbench, and the blade response is evaluated in time domain using Newmark-beta method. The response calculations have been performed for different values of spring and damping constants to identify their effect on the blade response. From these response curves, the relation between vibration amplitude and gap between the shrouds has been identified.
Turbine Blades
MTech Theses
Department of Mechanical Engineering
621.431 5 / Su46D