Compressor Wheel Thermal Insulating Coating for Creep Prevention
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Solution Overview
Problem
Turbocharger compressor wheels experience increased temperature and centrifugal stress at higher rotational speeds, leading to creep damage and reduced fastening force due to high centrifugal forces in high-temperature environments, which can result in efficiency loss and damage.
Innovation Solution
A compressor wheel with a thermal insulating coating layer covering at least a part of its back surface, made of aluminum or aluminum alloy, to reduce heat input from friction-generated heat, thereby suppressing temperature increase and preventing creep damage and fastening force reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the rotational speed of the compressor wheel increases to meet engine downsizing and high output power demands, then the output power is improved, but the temperature of the compressor wheel increases and centrifugal stress increases, leading to creep damage
Solution Approach 1:
A thermal insulating coating layer is applied to the back surface of the compressor wheel to act as an intermediary between the heat source (friction heat from high-speed rotation) and the compressor wheel body. This coating layer reduces heat input to the wheel, suppressing temperature increase and preventing creep damage while allowing the wheel to rotate at higher speeds for improved output power.
2Power
If the rotational speed of the compressor wheel increases, then the output power is improved, but the temperature increase causes the compressor wheel to contract in the axial direction, reducing fastening force
Solution Approach 1:
The thermal insulating coating layer serves as a mediator that reduces heat transfer to the compressor wheel body during high-speed rotation. By suppressing temperature increase, the coating prevents thermal contraction in the axial direction, thereby maintaining fastening force between the compressor wheel and rotational shaft even at high rotational speeds required for improved output power.
3Weight of moving object
If aluminum alloy is used as the compressor wheel material to achieve high strength, high stiffness, and light weight, then the weight is reduced and energy loss is decreased, but the material is susceptible to creep damage in high temperature environments
Solution Approach 1:
The thermal insulating coating layer acts as a protective intermediary between the aluminum alloy compressor wheel and the high-temperature environment generated during high-speed rotation. By reducing heat input to the aluminum alloy material, the coating enables the lightweight, high-strength benefits of aluminum alloy to be maintained while preventing creep damage that would otherwise occur in high-temperature conditions.
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 thermal insulating coating layer effectively reduces heat input, preventing damage and maintaining fastening force, thus enhancing the durability and efficiency of the compressor wheel.
Implementation Method 1
a thermal insulating coating layer disposed so as to cover at least a part of a back surface of the compressor wheel body
Implementation Method 2
heat generated by friction between the compressor wheel and the air around a back surface of the compressor wheel during high-speed rotation
Implementation Method 3
when the rotational speed of the compressor wheel increases, the centrifugal stress of the compressor wheel increases
Implementation Method 4
If high centrifugal force is continuously applied to the compressor wheel in a high temperature environment, the compressor wheel may contract in the axial direction of the rotational shaft due to creep deformation
Data Source
Figure 1
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Figure 3
AI summary
A compressor wheel includes a compressor wheel body, and a thermal insulating coating layer disposed so as to cover at least a part of a back surface of the compressor wheel body.