Turbine Casing Shape Modeling for Precise Rotor Clearance Assembly
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Solution Overview
Problem
The existing methods for assembling steam turbines require multiple temporary assemblies, which are labor-intensive and inefficient, and struggle to maintain the relative position of stationary and rotating bodies within precise allowable ranges.
Innovation Solution
A method involving the creation of reference and corrected shape models for turbine casing components, using measured and self-weighted shape data to simulate the assembly state, allowing for accurate calculation and adjustment of intervals between stationary and rotating bodies, thereby reducing the need for temporary assemblies and improving assembly efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple temporary assemblies are performed to measure distances between the virtual rotor and diaphragm, then the relative position measurement can be obtained, but the assembly process becomes labor-intensive and inefficient
Solution Approach 1:
The patent creates a virtual rotor model (copy of the actual rotor) and uses it to calculate the distance to the diaphragm. This virtual model allows multiple measurements and calculations to be performed without physical reassembly, eliminating the need for multiple temporary assemblies while maintaining measurement precision.
Solution Approach 2:
The patent performs preliminary calculations of the distance between the virtual rotor and diaphragm before actual assembly. By pre-calculating the required adjustments and positioning, the assembly process is streamlined, reducing the need for iterative temporary assemblies and improving overall assembly efficiency.
2Measurement precision
If the upper half outer casing and upper half inner casing are removed for measurement, then accurate distance measurement can be performed, but the assembly process becomes more complex and time-consuming
Solution Approach 1:
Instead of physically removing casings for measurement, the patent uses a virtual rotor model to calculate distances. This approach maintains measurement accuracy while avoiding the complexity of disassembly and reassembly operations.
Solution Approach 2:
The patent replaces physical measurement operations (which require disassembly) with computational calculations using a virtual model. This substitution eliminates the need to physically remove and reattach casings, reducing assembly process complexity while maintaining measurement accuracy.
3Manufacturing precision
If traditional temporary assembly methods are used to adjust the relative position, then the allowable range can be met, but labor consumption increases and efficiency decreases
Solution Approach 1:
The patent performs preliminary calculations to determine the exact positioning adjustments needed before assembly begins. By pre-determining the correct positions and adjustments, the actual assembly requires minimal iterative work, maintaining high precision while significantly improving productivity.
Solution Approach 2:
The virtual rotor model enables precise calculation of relative positions without requiring multiple physical trial assemblies. This computational approach achieves the same positioning accuracy as traditional methods but with far less labor and time.
Data Source
AI summary
In an assembly method for a turbine, measured shape data is acquired by measuring a shape for each of a plurality of casing components in a state in which the plurality of casing components are not fastened to each other. self-weighted state shape data, which is shape data when self-weight is applied, is created for each of the plurality of casing components. A reference shape model is corrected based on a difference between the measured shape data of a target measurement part and the self-weighted state shape data of the target measurement part. By using the corrected shape model, fastened state shape data, which is shape data in a state in which the plurality of casing components are fastened to each other, is estimated for each of the plurality of casing components.