Steam Turbine Seal Ring Covering Caulking Groove Mixing Loss
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Solution Overview
Problem
In steam turbines, the leakage flow of steam from the seal device merges with the main flow at a large inclination angle, causing increased mixing loss and performance deterioration due to the caulking groove's effect on the leakage flow.
Innovation Solution
A rotary machine design with a seal member that covers the caulking recessed portion and provides a flat surface for the leakage flow to merge smoothly with the main flow, reducing mixing loss by positioning the caulking recessed portion upstream and using a seal member with specific fin configurations to minimize interference and thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a caulking groove is provided upstream of the stator blade to fix the stator blade to the casing, then the stator blade is securely fixed to the casing, but the leakage flow of steam is affected by the caulking groove to become a vertical vortex flow, increasing mixing loss when merging with the main flow
Solution Approach 1:
The invention extracts the harmful effect of the caulking groove from the steam flow path by providing a seal member that covers the caulking groove. The seal member is disposed between the tip portion of the rotor blade and the inner peripheral surface of the casing, effectively blocking the steam from entering the caulking groove and forming vortex flow, thus removing the source of mixing loss while preserving the fixing function
Solution Approach 2:
The seal member acts as an intermediary element between the steam flow and the caulking groove. It prevents direct interaction between the leakage steam and the caulking groove structure, allowing the steam to flow smoothly without being disrupted by the groove, thereby eliminating vortex formation and reducing mixing loss
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
The design improves performance by reducing mixing loss in the merge portion, allowing the leakage flow to merge smoothly with the main flow, thereby enhancing the efficiency of the steam turbine.
Implementation Method 1
A plurality of seal fins are provided in the tip portion of the rotor blade or an inner surface of the casing to form the labyrinth seal. Since gaps are formed between the plurality of seal fins and the inner surface of the casing or the tip portion of the rotor blade to generate pressure loss, a leakage flow of the steam in the axial direction is suppressed by the pressure loss.
Implementation Method 2
Since gaps are formed between the plurality of seal fins and the inner surface of the casing or the tip portion of the rotor blade to generate pressure loss, a leakage flow of the steam in the axial direction is suppressed by the pressure loss.
Data Source
AI summary
In a rotary machine and a seal member, a casing, a rotor, a stator blade, a rotor blade, and a seal device disposed between the casing and a tip portion of the rotor blade are provided, in which a blade attachment groove is provided in the inner peripheral portion of the casing, and a caulking groove is provided adjacent to the blade attachment groove, in which a base end portion of the stator blade is mounted in the blade attachment groove and a caulking member is locked to the caulking groove and a blade root portion of the stator blade, so that the stator blade is fixed to the inner peripheral portion of the casing, and in which a seal ring as a seal device is mounted in the inner peripheral portion of the casing, and the seal ring covers at least a part of the caulking groove.