Turbine Housing Centering Device for Thermal Expansion
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Solution Overview
Problem
Conventional heat centering methods for turbine housings in turbo systems result in uneven thermal expansion, leading to larger clearances between the turbine wheel and casing, which negatively impact turbine efficiency during transient operation conditions.
Innovation Solution
A ring-shaped centering device with a ratio of outer to inner diameter ≤2, featuring centering elements that allow radial thermal expansion and engage with complementary elements on the bearing housing, ensuring consistent contact and minimizing clearances between the turbine wheel and housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional heat centering methods are used with a heat shield or nozzle ring, then the turbine housing can be centered with respect to the radial turbine, but equally fast heat transfer from exhaust gas to the heat centering element cannot be assured, leading to larger clearances being required
Solution Approach 1:
The heat centering element is divided into multiple independent heat centering elements (at least two) arranged around the exhaust gas flow path. Each element independently receives heat from the exhaust gas and expands radially to center the turbine housing. This segmentation ensures that heat transfer occurs at multiple discrete locations, improving uniformity and reliability compared to a single large heat shield.
Solution Approach 2:
Multiple heat centering elements are strategically positioned at specific locations around the exhaust gas flow to create localized heat transfer zones. This allows heat to be applied at multiple critical points simultaneously, ensuring more uniform thermal expansion and centering action throughout the turbine housing assembly.
2Reliability
If larger clearances are provided between turbine wheel and turbine casing to accommodate transient operation conditions, then reliable operation is ensured, but turbine efficiency deteriorates
Solution Approach 1:
The system dynamically changes the clearance parameter between turbine wheel and casing by utilizing thermal expansion of multiple heat centering elements. During transient operation, the elements expand radially in response to exhaust gas heat, automatically reducing clearances to optimal values without requiring oversized initial clearances, thereby maintaining both reliability and efficiency.
3Manufacturing precision
If a ring-shaped centering device with small D1/D2 ratio is used, then radial thermal expansion is improved and centering precision is enhanced, but the device complexity increases due to multiple centering elements
Solution Approach 1:
Each heat centering element serves multiple functions: it acts as a thermal conduit to receive heat from exhaust gas, serves as a mechanical expansion element to center the housing, and provides structural support. This multi-functionality reduces the need for separate components, offsetting the complexity increase from having multiple elements.
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 centering device improves turbine housing alignment at both transient and stationary operations, reducing clearances and enhancing turbine efficiency by allowing radial thermal expansion and maintaining continuous heat transfer from exhaust gas.
Implementation Method 1
The two or more centering elements are configured for allowing a radial thermal expansion of the ring-shaped body during engagement of the two or more centering elements with the respective complementary centering elements
Implementation Method 2
transmitting heat from exhaust gas to a centering device according to embodiments described herein
Data Source
AI summary
A centering device (10) for centering a turbine housing (40) with respect to a central axis (33) of a radial turbine of a turbo system is described. The centering device (10) includes a ring-shaped body (11) having an outer diameter D1 and an inner diameter D2, wherein a ratio of D1/D2 is ≤2. Additionally, the centering device (10) includes two or more centering elements (16) provided on a side surface (12) of the ring-shaped body (11) for engaging with respective complementary centering elements (21) provided on a bearing housing (20). The two or more centering elements (16) are configured for allowing a radial thermal expansion of the ring-shaped body (11) during engagement of the two or more centering elements (16) with the respective complementary centering elements (21). Further, a turbo system, including such a centering device as well as a method of centering a turbine housing are described.