Steam Turbine Casing Height Adjustment for Blade Clearance
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Solution Overview
Problem
Existing steam turbine designs face challenges in maintaining a suitable clearance between the turbine blade and the casing due to thermal expansion, leading to relative movement and changes in clearance, which existing solutions fail to adequately address.
Innovation Solution
A rotary machine with a height adjustment mechanism featuring inclined surfaces on the support legs and bases, along with an actuator, allows for precise adjustment of the casing's position relative to the rotary shaft, maintaining appropriate clearance and preventing interference between the turbine blade and the casing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the steam turbine operates at high temperature, then power generation efficiency is improved, but thermal expansion causes relative movement between the rotary shaft and casing, leading to clearance changes
Solution Approach 1:
The invention makes the support leg base movable relative to the support leg by providing an inclined surface and actuator mechanism. This dynamic adjustment capability allows the casing position to be changed in response to thermal expansion during operation, thereby maintaining appropriate clearance between the turbine blade and casing while operating at high temperature for power generation
Solution Approach 2:
The invention changes the position parameter of the casing by moving the support leg base along the inclined surface. The actuator adjusts the distance between the support leg base and support leg, which directly changes the height position of the casing relative to the rotary shaft, compensating for thermal expansion effects and maintaining optimal clearance
2Reliability
If the casing and support legs are made from different materials to withstand thermal conditions, then operational reliability is improved, but differential thermal expansion causes relative displacement and clearance changes
Solution Approach 1:
The movable support leg base design allows the system to dynamically compensate for differential thermal expansion between different materials. The actuator mechanism adjusts the relative position between support leg and base, counteracting the relative displacement caused by different thermal expansion rates of casing and support leg materials
Solution Approach 2:
The invention employs clearance detection means to monitor the clearance between turbine blade and casing, and actuator control means to adjust the support leg base position based on detected clearance values. This feedback control system maintains appropriate clearance despite differential thermal expansion from using different materials for casing and support legs
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 mechanism effectively adjusts the casing's height to maintain suitable clearance, preventing inappropriate changes and ensuring smooth operation by allowing for independent displacement of support legs and synchronized movement, thus enhancing operational efficiency.
Implementation Method 1
an inclined surface of a support leg formed on the support leg, an inclined surface of a support leg base formed on the support leg base while facing the inclined surface of the support leg, and an actuator configured to move the support leg and the support leg base relative to each other
Implementation Method 2
the steam turbine itself becomes hot during operation, and its components undergo thermal expansion. This displaces the rotary shaft upward from the position where the rotary shaft is located before when the turbine is in operation due to thermal expansion of a bearing and the like supporting the rotary shaft, and also displaces the casing upward
Data Source
AI summary
A rotary machine includes: a rotary shaft supported by a bearing provided on a bearing base; and a casing housing the rotary shaft at least in part. The casing includes at least one support leg configured to support the casing on a base plate of a support structure member, and a support leg of the at least one support leg is supported on a support leg base provided on the base plate. The rotary machine further includes a height adjustment mechanism configured to adjust height of the casing, and the height adjustment mechanism includes an inclined surface of a support leg formed on the support leg, an inclined surface of a support leg base formed on the support leg base while facing the inclined surface of the support leg, and an actuator configured to move the support leg and the support leg base relative to each other.