Turbine Casing Assembly Using Measured Deformation Prediction
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Solution Overview
Problem
The assembly of turbines is hindered by the deformation of casing halves due to their weight and the difficulty in maintaining a precise gap between the stationary and rotary bodies, leading to inefficiencies and inaccuracies in the assembly process.
Innovation Solution
A computer-implemented method using a finite element model corrected with actual measurement data to simulate and predict the deformation of turbine components, allowing for precise positioning adjustments without a temporary assembly process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a temporary assembly process is performed to measure deformation before final assembly, then assembly accuracy is improved, but assembly time and labor cost increase significantly
Solution Approach 1:
The invention performs preliminary measurement of the casing's three-dimensional configuration and preliminary calculation of deformation amounts using finite element analysis before the actual assembly process. This allows the stationary body to be positioned in advance with predicted deformation compensation, eliminating the need for time-consuming temporary assembly while maintaining high assembly accuracy.
Solution Approach 2:
The invention creates a virtual model (finite element model) that replicates the casing's physical properties and deformation characteristics. By measuring the actual casing and creating a corresponding digital twin, the system can simulate and predict deformation behavior without requiring physical temporary assembly, thus saving time while preserving measurement accuracy.
2Strength
If thermal shrinking is used to fasten bolts for temporary assembly, then fastening force is improved, but cooling time and process complexity increase
Solution Approach 1:
The invention replaces the thermal shrinking process with a calculation-based approach. Instead of physically heating and cooling bolts to generate fastening force, the system calculates the deformation amounts that would occur during thermal shrinking and uses these calculations to pre-position components, thereby eliminating the time-consuming thermal process while achieving the same positioning accuracy.
Solution Approach 2:
The invention performs preliminary calculation of the deformation amounts that would result from thermal shrinking fastening. By computing these deformation values in advance using finite element analysis, the system can compensate for them in the initial positioning, eliminating the need to actually perform the thermal shrinking process during assembly.
3Ease of manufacture
If actual measurement data from previous assemblies is used for evaluation, then process simplicity is improved, but accuracy is reduced due to individual variations in configuration and material
Solution Approach 1:
The invention measures and analyzes the specific local characteristics of the actual casing being assembled, including its unique three-dimensional configuration and material properties. By creating a customized finite element model based on the actual measured data of each specific casing, the system accounts for individual variations while maintaining process efficiency, achieving both accuracy and simplicity.
Solution Approach 2:
The invention changes the approach from using fixed historical measurement data to dynamically adjusting parameters based on actual measured characteristics of each casing. By inputting real measurement data into the finite element model and recalculating deformation amounts for each specific case, the system adapts to individual variations in configuration and material, thereby improving accuracy without significantly increasing complexity.
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
Enables high-accuracy turbine assembly in a reduced time frame by accurately estimating and adjusting for the deformation of evaluated portions, thereby omitting labor-intensive temporary assembly steps.
Implementation Method 1
the casing of a turbine is divided into upper and lower half parts... they slightly bend due to their own weight
Implementation Method 2
thermal shrinking is performed as in the case of the final assembly. The thermal shrinking is a fastening method in which a nut is threadedly engaged with a bolt expanded through heating and in which the fastening force is increased by utilizing contraction of the bolt
Data Source
Figure 1~2
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Figure 5~6
AI summary
In assembling a turbine 1 including: a casing 10 consisting of an upper half part 11b, 12b and a lower half part 11a, 12a fastened together by bolts 14; a stationary body 20 accommodated in the casing 10 and supported by the lower half part 11a, 12a; and a rotary body 30 supported by a plurality of bearings 33 so as to be situated on the inner side of the stationary body 20, there are executed: a procedure of reading a finite element model of the three-dimensional configuration of the turbine; a reading procedure of reading actual measurement information on the three-dimensional configuration of the upper half part 11b, 12b and the lower half part 11a, 12a of the casing 10 in the open state; a model correction procedure of reflecting actual measurement information of an evaluated portion that is a specific part of the casing 10 in the finite element model and generating a correction model obtained through correction of the finite element model; a deformation amount estimation procedure of estimating the movement amount of the evaluated portion generated when the upper half part 11b, 12b and the lower half part 11a, 12a of the casing 10 are fastened together by the bolts 14 through simulation using the correction model; and an output procedure of outputting an estimated value of the movement amount to an output device 48. Fig. 13