Numerical Investigation of Non-synchronous Blade Vibration in a Transonic

Numerical Investigation of Non-synchronous Blade Vibration in a Transonic Compressor Front Stage

A Snapshot of Your Day

Compressor rotor blade vibrations are commonly categorized as either synchronous or non-synchronous occurrences. Forced response in rotor blades occurs due to circumferential flow disturbances, such as those created by wakes and potential fields. As these excitations remain constant from the stationary frame of reference, their frequencies align with integer multiples of the vane passing frequency, resulting in synchronous coupling with the rotor speed. The mechanisms responsible for synchronous vibrations are generally well understood.

Flutter is a non-synchronous aeroelastic phenomenon, often described as a self-excited excitation sustained and amplified through a feedback mechanism between the fluid and blade vibration. On the other hand, Non-Synchronous Vibration (NSV) encompasses a subset of non-linear aerodynamic mechanisms that lock-in with the structure when the frequency of pressure fluctuations matches the structural natural frequency. Unlike Flutter, the onset of these NSV mechanisms and the frequency of the unsteady aerodynamic fluctuations are independent of the blade vibration. The fluctuations lock-in to the structure might establish if the displacement amplitude exceeds a specific threshold.

Non-synchronous vibration can result in significant vibration amplitudes and sudden blade failure, thereby limiting the operational envelope of the compressor. Various mechanisms, originating from different aerodynamic features such as tip gap vortices, leading edge separation, vortex shedding, and shock-boundary layer interactions, can lead to the onset of non-synchronous vibrations. In recent years, there has been a strong focus on NSV research aimed at understanding the primary drivers and developing preventive measures.

This project aims to investigate NSV mechanisms in an axial transonic compressor. The student will conduct Unsteady Reynolds-averaged Navier–Stokes simulations using a full-annulus model at both on-design and off-design operating conditions. A comprehensive assessment of the flow field and unsteady pressure data will be used to ascertain the potential to predict the onset and flow characteristics of non-synchronous flow phenomena with the proposed methods.

How You’ll Make an Impact

● Conduct a comprehensive literature review on the current state-of-the-art regarding the effects of non-synchronous vibration (NSV) in transonic axial compressors.
● Perform detailed CFD simulations to analyze the NSV mechanisms.
● Conduct a thorough analysis of the simulation data to identify and interpret key trends and findings.
● Prepare a comprehensive report and deliver a presentation to facilitate discussion and examination of the results.

What You Bring

● M.Sc. student with mechanical engineering, aerospace engineering, engineering physics or similar.
● Experience and interests in using CFD tools, e.g., CFX, STAR-CCM+, Turbostream, TRACE, or others
● Programming skills with Matlab and/or Python.
● Experience with solid mechanics, structural dynamics and FEM is an advantage.
● Ability to work independently, but not afraid of asking questions to move forward in your work
● Is structured and communicates well.
● Can find own ways and solutions to challenges and problems.

About the Team

Our Gas Services division offers Low-emission power generation through service and decarbonization. Zero or low emission power generation and all gas turbines under one roof, steam turbines and generators. Decarbonization opportunities through service offerings, modernization, and digitalization of the fleet.
We can offer you employment benefits such as: reduction of working hours, advance vacation, health care allowance and an eventual possibility to a flexible working place.

Who is Siemens Energy?

At Siemens Energy, we are more than just an energy technology company. We meet the growing energy demand across 90+ countries while ensuring our climate is protected. With more than 99,000 dedicated employees, we not only generate electricity for over 16% of the global community, but we’re also using our technology to help protect people and the environment.

Our global team is committed to making sustainable, reliable, and affordable energy a reality by pushing the boundaries of what is possible. We uphold a 150-year legacy of innovation that encourages our search for people who will support our focus on decarbonization, new technologies, and energy transformation.

Find out how you can make a difference at Siemens Energy: https://www.siemens-energy.com/employeevideo

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Application
Don’t hesitate – apply via https://jobs.siemens-energy.com/en_US/jobs , id nr 264821 no later than 2024-11-01.

Ongoing selection is applied, the role might be filled before last application date.
For questions about the role, please contact the recruiting manager Henrik Pilvinge on henrik.pilvinge@siemens-energy.com.
For questions about the recruitment process please contact the responsible recruiter Ermina Imamovic on ermina.imamovic.ext@siemens-energy.com

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