Turbomachine Inner Outer Casing Seal Assembly
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Solution Overview
Problem
The existing turbomachines face challenges in sealing between annular inner and outer casings due to different expansion rates caused by varying gas stream temperatures, leading to leakage issues that traditional leaf-type seals struggle to address effectively.
Innovation Solution
An annular seal assembly is designed with forward and aft seal passages, featuring seal members with recessed and connecting portions that allow for radial and axial expansions, misalignments, and contractions, ensuring effective sealing by floating within the seal passages and accommodating intersegment gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional leaf-type seals are used between annular inner and outer casings, then sealing is provided, but leakage occurs due to different expansion rates caused by varying gas stream temperatures
Solution Approach 1:
The seal assembly is designed to float within the seal passages, allowing it to dynamically adjust its position and configuration in response to thermal expansion differences between the inner and outer casings. This dynamic adaptation maintains sealing contact despite relative movement, preventing fluid leakage while accommodating temperature-induced dimensional changes.
Solution Approach 2:
The seal members are configured with recessed and connecting portions that change their effective sealing parameters (position, orientation, contact pressure) in response to thermal expansion. This parameter adjustment allows the seal to maintain effectiveness under varying temperature conditions and expansion rates.
2Adaptability or versatility
If the annular inner casing is exposed to higher temperature gas streams, then turbine nozzle and shroud support is achieved, but different expansion rates relative to the outer casing occur
Solution Approach 1:
The seal assembly is segmented into multiple seal members with recessed and connecting portions, allowing each segment to independently accommodate thermal expansion. This segmentation enables the seal to handle differential expansion between the high-temperature inner casing and the outer casing while maintaining overall sealing integrity.
Solution Approach 2:
The floating seal assembly acts as an intermediary element between the inner and outer casings, mediating the effects of differential thermal expansion. It absorbs and accommodates the relative movement caused by different expansion rates while maintaining the sealing function.
3Adaptability or versatility
If leaf-type seals are arranged in an arcuate end-to-end relationship, then intersegment gaps are created to accommodate axial expansions, but sealing areas are compromised
Solution Approach 1:
The seal members feature nested recessed and connecting portions that interlock while maintaining continuous sealing contact. This nesting arrangement allows axial expansion accommodation through the connecting portions while the recessed portions maintain sealing area continuity, eliminating the gaps problem of traditional end-to-end arrangements.
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 solution effectively reduces fluid leakage between the inner and outer casings, maintaining sealing effectiveness despite thermal expansion differences and misalignments, enhancing the operational efficiency of turbomachines.
Implementation Method 1
seal members with recessed and connecting portions that allow for radial and axial expansions, misalignments, and contractions, ensuring effective sealing by floating within the seal passages
Implementation Method 2
Exposure to gas streams at different temperatures leads to different expansion rates for each of the annular inner and outer casings
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A turbomachine includes an inner casing component (20) having a first end that extends to a second end and a seal member (58). An outer casing component (30) is coupled to the inner casing component (20). The annular outer casing component (30) includes a first end portion (71) that extends to a second end portion (72) and a seal element (78) that aligns with the seal member (58) of the annular inner casing component (20) to form a seal passage (86). A seal (36) is arranged in the seal passage (86). The seal (36) includes a first end section (94) that extends to a second end section (95) through an intermediate zone (96). The first end section (94) includes a recessed portion (99) and the second end section (95) includes a connecting portion (100). The connecting portion (100) is configured and disposed to nest within the recessed portion (99) to form a substantially continuous seal. A corresponding method of sealing a turbomachine innner to outer casin interface.