Rotor Thermal Gradient Control for Transversal Oscillation Stability
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Solution Overview
Problem
Rotor systems in turbomachines experience thermal gradients due to the Morton effect, leading to unbalanced thermal deformation and transversal oscillations, which can cause instability and potential failure, as existing solutions only address oscillations after they occur, failing to prevent their origin.
Innovation Solution
A method and device that measure transversal oscillations, estimate thermal gradients, and compute actuation parameters to emit signals that apply corrective forces to stabilize the rotor, using sensors, actuators, and a control unit with processing and storage modules to manage thermal gradients and prevent instability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing oscillation correction systems are used, then rotor oscillations can be corrected after they occur, but the system cannot prevent the origin of unwanted oscillations and only works ex-post
Solution Approach 1:
The system performs preliminary action by estimating the thermal gradient from vibration signals and computing actuation parameters before the thermal deformation fully develops. The actuator applies corrective forces proactively based on predicted thermal behavior, preventing oscillations rather than merely correcting them after occurrence.
Solution Approach 2:
The system implements feedback by continuously monitoring rotor vibration signals, estimating thermal gradients from these signals, and adjusting actuator forces accordingly. The control unit uses the measured vibration data to compute actuation parameters that counteract the developing thermal deformation, creating a closed-loop control system.
2Device complexity
If thermal gradients are allowed to develop naturally, then the rotor operates without active intervention, but thermal deformation causes unbalance and rotor oscillations leading to instability
Solution Approach 1:
The actuator serves as an intermediary element that applies corrective forces to the rotor to counteract thermal deformation. The control unit acts as a mediator between the vibration sensors and the actuator, processing vibration signals to estimate thermal gradients and computing appropriate actuation commands to maintain rotor stability.
3Reliability
If proactive thermal gradient compensation is implemented, then rotor stability is maintained, but additional control systems and actuators are required
Solution Approach 1:
The control unit performs multiple functions: it acquires vibration signals from sensors, estimates thermal gradients from these signals, computes actuation parameters, and generates control commands for the actuator. This multi-functional approach consolidates control system complexity into a single processing unit rather than requiring separate dedicated systems for each function.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively prevents thermal-induced oscillations from affecting rotor performance, providing proactive stabilization against thermal deformation and unbalance.
Implementation Method 1
acquiring a first signal representing a value of transversal oscillations of a rotor
Implementation Method 2
a thermal-fluidodynamic interaction known as the Morton effect. Indeed, because of unavoidable rotor residual unbalance, the rotor does not revolve around a fixed axis of rotation but, on the contrary, has a small precession movement. Such a precession movement causes that one part of the rotor is always exposed to a minimum clearance with respect to the opposite side. Due to the different clearance, the same part is exposed to higher fluid velocity with respect to the other side. As a result, due to fluid viscous dissipation, one part of the rotor heats more than the opposite part, which subject the rotor itself to a thermal gradient
Implementation Method 3
An actuator configured to apply a transversal force to the rotor
Data Source
AI summary
A method for stabilizing transversal oscillations of a rotor including the steps of acquiring a first signal representing a value of transversal oscillations of a rotor; estimating a value of a thermal gradient from the first signal; computing a value of an actuation parameter from the value of thermal gradient; emitting an actuation signal representing the value of the actuation parameter.