Split Compressor Casing With Compliant Joint for Thermal Expansion
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Solution Overview
Problem
Multi-stage centrifugal compressors experience reduced efficiency and operational flexibility due to differential thermal expansion of components caused by heat generation during compression, leading to potential damage and restricted operational times.
Innovation Solution
Incorporation of a compliant element in the joint interface between the inner and outer casings to allow for movement along the rotational axis in response to thermal expansion, accommodating differential thermal expansion without damaging the components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compressor operates for extended periods or with frequent start-ups, then productivity and operational flexibility improve, but differential thermal expansion increases causing component damage and reducing reliability
Solution Approach 1:
The casing is divided into inner and outer segments that can move independently relative to each other. The inner casing is separated from the outer casing through compliant elements, allowing each segment to accommodate thermal expansion independently while maintaining overall structural integrity.
Solution Approach 2:
The compliant elements change their mechanical properties (flexibility) in response to temperature changes. As temperature increases during operation, the compliant elements become more flexible, allowing the inner casing to expand axially without generating damaging thermal stresses.
2Manufacturing precision
If rigid joint interfaces are used between casings, then manufacturing precision and structural integrity improve, but thermal stress and distortion increase during operation
Solution Approach 1:
Compliant elements function as flexible mechanical features within the joint interface that allow controlled movement and deformation. These elements accommodate thermal expansion while maintaining the joint connection, preventing the buildup of thermal stresses that would occur with completely rigid interfaces.
Solution Approach 2:
The joint interface transitions from a static rigid connection to a dynamic system where the compliant elements can deform and move in response to thermal conditions. This dynamic capability allows the joint to adapt to changing thermal states without compromising structural integrity.
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
Enhances component life, reduces maintenance, and allows for more flexible operational start-ups and shut-downs by mitigating thermal stress and distortion.
Implementation Method 1
a compliant element formed as part of one of the first joint interface and the second joint interface and arranged to allow for movement of the second joint interface along the rotational axis in response to thermal expansion of the inner casing
Data Source
AI summary
A machine includes a rotor supported for rotation about a rotational axis, an outer casing having an inner bore, and an inner casing disposed within the inner bore and surrounding a portion of the rotor, the inner casing including a first joint interface. A head member is disposed within the inner bore and includes a first joint interface that engages a second joint interface to form a joint therebetween. A compliant element is formed as part of the first joint interface and arranged to allow for movement of the second joint interface along the rotational axis in response to the thermal expansion of the inner casing.