Turbomachine Rotor Blade Socket for High-Speed Bonded Joints
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Solution Overview
Problem
Existing turbomachine rotors face limitations in operating at higher rotational speeds due to the failure of firmly bonded connections between moving blades and hub or shroud elements at increased speeds, which restricts performance enhancement.
Innovation Solution
Incorporating an integral base on the moving blades, connected firmly to either the shroud or hub element, with a transition radius between 0.5% and 2.5% of the rotor's outer diameter, to reduce stresses and enhance the bonded connection, allowing for higher rotational speeds through methods like milling and soldering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the moving blades are firmly bonded to the hub element or shroud element, then the structural integrity is improved, but the rotor cannot operate at higher rotational speeds due to connection failure
Solution Approach 1:
The moving blade is divided into three distinct parts: a base portion, a transition region, and a blade leaf. This segmentation allows each part to be optimized independently - the base for bonding strength, the transition region for stress distribution, and the leaf for aerodynamic function. The base is further segmented into a bonding surface and a support surface, enabling specialized design for each functional requirement.
Solution Approach 2:
Different regions of the moving blade are given different geometric properties and material characteristics. The base has a large bonding surface area for strong attachment, the transition region has a specific radius (0.5%-2.5% of rotor outer diameter) to optimize stress distribution, and the blade leaf has aerodynamic shaping. This local optimization allows the connection to withstand higher rotational speeds while maintaining overall blade functionality.
2Ease of manufacture
If the moving blades and hub element form a monolithic assembly, then manufacturing is simplified, but the bonded connection fails at high rotational speeds
Solution Approach 1:
The base of the moving blade is pre-formed with an optimized geometry including a specific transition radius (0.5%-2.5% of rotor outer diameter) and a dedicated bonding surface area that is at least 1.5 times the support surface area. This preliminary design of the bonding interface ensures that when the blade is subsequently bonded to the hub or shroud element, the connection can withstand high rotational speeds without failure, while still allowing for efficient manufacturing processes like milling and soldering.
3Strength
If the transition radius between moving blade leaf and base is increased, then the bonded connection strength is improved, but the manufacturing complexity increases
Solution Approach 1:
The transition radius in the transition region is optimized to a specific range (0.5%-2.5% of the rotor's outer diameter, preferably 1.0%-2.0%). This parameter optimization provides the best balance between connection strength and manufacturing feasibility. The base area ratio (bonding surface to support surface) is also optimized to at least 1.5:1, ensuring adequate bonding area without excessive material usage or manufacturing complexity.
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
This design enables turbomachine rotors to operate at higher speeds, thereby increasing performance by reducing stress and strengthening the bonded connection, allowing for higher rotational speeds and improved efficiency.
Implementation Method 1
the moving blades and the shroud element or according to the second alternative the moving blades and the hub element are connected to one another at the bases of the moving blades by soldering
Data Source
AI summary
A turbomachine rotor having a radially inner hub element, a radially outer cover element, and rotor blades which extend between the hub element and the cover element and have rotor blade airfoils. The rotor blades are an integral component of the hub element and are bonded to the cover element according to a first alternative or are an integral component of the cover element and are bonded to the hub element according to a second alternative. The rotor blades have an integral socket adjacently to the cover element according to the first alternative or adjacently to the hub element according to the second alternative, and the rotor blades are bonded to the cover element according to the first alternative or to the hub element according to the second alternative via the socket.