Integral Scroll Casing for Rotary Machine Thermal Stress Relief
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Solution Overview
Problem
Conventional rotary machine scroll structures divided into two pieces increase size, weight, and material costs, and suffer from fluid leaks and pressure losses due to bolt fastening and limited aerodynamic channel shapes.
Innovation Solution
An integrally formed scroll structure with a single-piece casing that allows for a more compact design, reduced pressure loss, and enhanced fluid handling, supported by radial expansion and contraction fittings to prevent misalignment and thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the scroll structure is divided into two pieces (upper casing and lower casing) and fastened using bolts, then the assembly and disassembly operation is facilitated, but the scroll structure increases in size and weight, and working fluid may leak from the joint surface
Solution Approach 1:
The patent merges the upper casing and lower casing into a single integrally formed scroll structure. This eliminates the need for separate pieces and bolt fastening, thereby reducing the weight and size of the scroll structure while preventing working fluid leakage from joint surfaces. The integral formation maintains the operational advantage of easy assembly and disassembly by simplifying the overall structure.
2Ease of operation
If the scroll structure is divided into two pieces with connecting flanges, then the assembly operation is facilitated, but the scroll structure increases in size and the weight and material cost of the turbine increase
Solution Approach 1:
The patent combines the upper and lower casings into one integral scroll structure, eliminating the need for connecting flanges and separate pieces. This merging reduces the overall volume and size of the scroll structure, thereby reducing the weight and material costs of the turbine while maintaining ease of assembly operation through simplified construction.
3Ease of operation
If the upper casing and lower casing are fastened using bolts, then the assembly and disassembly is enabled, but the shape of the channel in the scroll structure is limited and aerodynamic performance is compromised
Solution Approach 1:
The patent integrates the channel shape design into the single-piece scroll structure, allowing for optimized aerodynamic forms without the constraints imposed by bolt fastening requirements. The integral formation enables smoother, more efficient channel geometries that reduce working fluid pressure loss and improve turbine performance while maintaining operational accessibility.
4Ease of operation
If the scroll structure uses a joint surface between upper and lower casings, then assembly is enabled, but working fluid leaks from the joint surface and external fluid is inhaled from outside
Solution Approach 1:
The patent eliminates the joint surface by forming the scroll structure as a single integral piece. This merging of the upper and lower casings into one continuous structure completely prevents working fluid leakage from joint surfaces and blocks the path for external fluid inhalation, thereby significantly improving the reliability and sealing performance of the scroll structure.
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 improves the reliability and performance of rotary machines by preventing fluid leaks, reducing size and pressure loss, and allowing for more efficient aerodynamic channel designs, while supporting the casing to prevent thermal deformation and misalignment.
Implementation Method 1
a fitting portion which supports the casing so as to allow the casing to expand and contract in a radial direction
Implementation Method 2
an outer peripheral surface of the scroll structure is sprayed with cooling fluid to decrease the temperature of the scroll structure
Implementation Method 3
the scroll structure has a heat shield effect with respect to a peripheral stationary member... the scroll structure shields radiant and heat transfer from the working fluid
Data Source
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AI summary
To provide a scroll structure of a rotary machine and a rotary machine in which it is possible to achieve an improvement in reliability and functionality of a rotary machine such as a turbine and to achieve a reduction in size of the rotary machine and the scroll structure. Provided are a casing (21) that entirely covers an area surrounding an annular channel extending in a circular shape about a rotational axis in a rotating portion of a rotary machine and a cylindrical channel extending from the annular channel at the rotational axis side and extending towards the rotating portion; and a fitting portion (23A) that supports the casing (21) with respect to a support portion accommodating the casing (21) so as to enable expansion and contraction in a radial direction centered on the rotational axis.