Turboengine Rotor Service Life Determination via Pyrometer
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Solution Overview
Problem
Existing methods for determining the remaining service life of rotors in thermally loaded turboengines, such as steam turbines, are complex, inflexible, and unreliable due to indirect temperature measurement methods, which fail to accurately account for high temperature gradients and cyclic heat stresses, especially during rapid transient processes.
Innovation Solution
A method involving direct contactless temperature measurement using a pyrometer to derive thermal stress on the rotor, allowing for precise calculation of remaining service life, with the pyrometer positioned on the casing opposite the rotor's inlet region to measure thermal radiation and synchronize with rotor rotation for consistent readings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If indirect temperature measurement methods (thermoelements in casing) are used, then the measurement setup is simpler, but the temperature measurement precision is insufficient and leads to large errors in stress calculation
Solution Approach 1:
The patent replaces contact-based mechanical temperature measurement systems (thermoelements requiring physical access to rotor) with optical measurement methods (pyrometer) that can non-contactly measure temperature from a distance, eliminating the need for complex mechanical access systems while achieving direct and accurate temperature measurement at the rotor inlet region
Solution Approach 2:
The patent introduces an intermediary measurement approach by measuring temperature at the rotor inlet region (where steam directly contacts the rotor) rather than attempting to measure at the rotor surface directly, allowing indirect but accurate determination of rotor temperature through the inlet region temperature field
2Reliability
If material samples are taken from rotor disks for fatigue testing, then the remaining service life can be determined, but the method becomes highly complicated and inflexible
Solution Approach 1:
The patent enables the rotor to essentially monitor its own service life by continuously measuring its operational parameters (temperature, stress) during normal operation, eliminating the need for external sample removal and laboratory testing, thus achieving reliable service life determination without complex intervention procedures
Solution Approach 2:
The patent establishes continuous monitoring of rotor temperature and stress during operation, allowing ongoing service life assessment without interrupting the turbine operation for sample removal, thereby maintaining continuous useful action and avoiding the complexity of periodic shutdown procedures
3Reliability
If hardness measurements are performed at periodic intervals, then service life can be estimated, but access to the stationary machine is required making it complicated
Solution Approach 1:
The patent replaces mechanical access requirements (needing to physically reach the rotor for hardness measurement) with non-contact optical measurement methods that can assess rotor conditions remotely during operation, making the measurement process simple and eliminating the complexity of machine shutdown and physical access procedures
4Measurement precision
If temperature is measured at various points of the inner casing, then temperature data is obtained, but the transfer function approach fails to accurately account for high temperature gradients during rapid transient processes
Solution Approach 1:
The patent shifts the measurement location from the inner casing (indirect dimension) to the rotor inlet region (direct dimension), where temperature can be measured at the source of the thermal load, enabling accurate capture of high temperature gradients during rapid transient processes without relying on slow responding transfer functions
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
This approach provides a flexible, reliable, and simplified method for determining rotor service life, reducing mechanical stress errors and enabling optimized operation by directly measuring critical temperatures, thus extending rotor lifespan and improving operational efficiency.
Implementation Method 1
A contactlessly operating temperature recorder, which records the temperature at the predetermined point, of the rotor is arranged on the casing
Data Source
AI summary
A method for determining the remaining service life of a rotor of a thermally loaded turboengine in which a temperature on the rotor is determined. Thermal stress on the rotor is calculated from the determined temperature, and the remaining service life of the rotor is calculated from the derived thermal stress. The temperature is measured directly at a predetermined point of the rotor, and the thermal stress on the rotor is derived from the measured temperature.