Internal Epicyclic Gearbox for Multistage Expander Speed Control
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Solution Overview
Problem
Current axial multistage expanders require high rotational speeds for efficient operation, leading to increased component stress and costs, and often necessitate external gearboxes that reduce overall efficiency and increase complexity, while also limiting turbomachinery operability and maintenance.
Innovation Solution
An axial multistage expander design with an internal gearbox, specifically an epicyclic gearbox, allows for different rotational speeds among stages, eliminating the need for external gearboxes and enabling direct connection to driven machines, thereby reducing complexity and costs while improving efficiency and operability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high rotational speed is used for axial multistage expander stages, then efficiency is improved, but component stress and costs increase
Solution Approach 1:
The expander is divided into multiple stages with independent rotational speed control. Each stage can operate at its optimal speed, allowing the first stage to run at high speed for efficiency while subsequent stages operate at lower speeds, reducing component stress and costs.
Solution Approach 2:
The system employs variable rotational speeds for different stages rather than a fixed uniform speed. The gearbox enables dynamic speed adjustment where the first stage rotates at a different speed than subsequent stages, optimizing both efficiency and component stress management.
2Speed
If external gearbox is used to match rotational speeds, then speed matching is achieved, but overall efficiency is reduced and complexity increases
Solution Approach 1:
The gearbox is integrated inside the expander housing rather than being an external separate unit. This merging of the gearbox with the expander reduces overall system complexity, eliminates external mechanical connections, and improves sealing while maintaining the speed matching function.
Solution Approach 2:
The gearbox is nested within the expander structure, with gear mechanisms positioned inside the housing. This nested arrangement allows the speed reduction mechanism to be contained within the existing expander footprint, reducing external complexity and improving compactness.
3Speed
If external gearbox is used, then speed matching is achieved, but maintenance difficulty increases
Solution Approach 1:
By integrating the gearbox inside the expander housing, the patent eliminates the need for separate external gearbox maintenance. The unified structure allows for easier access to both the expander and gearbox components through a single maintenance approach, reducing the complexity of repair operations.
4Device complexity
If uniform rotational speed is used for all stages, then simplicity is maintained, but aerodynamic performance and manufacturability are compromised
Solution Approach 1:
The expander stages are segmented with independent speed control, allowing each stage to operate at its aerodynamically optimal rotational speed. This segmentation enables precise control of airflow patterns and maintains manufacturability by allowing tailored design parameters for each stage.
Solution Approach 2:
Different stages are assigned different rotational speeds based on their specific aerodynamic requirements. The first stage operates at a different speed than subsequent stages, with each stage's speed optimized for its local aerodynamic performance and manufacturing considerations.
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 internal gearbox configuration allows for optimized rotational speed management across stages, enhancing the expander's efficiency, reducing costs, and simplifying the system, while maintaining manufacturability and aerodynamic performance.
Implementation Method 1
The rotoric airfoils extract the energy from the gas and convert it into rotational energy through the rotor 20 and shaft 22
Implementation Method 2
This expansion process results in a temperature drop in addition to recovery of the pressure energy
Data Source
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AI summary
A geared axial multistage expander system and assembly method including a casing (42) and a plurality of stages (R1 to R6). A stage includes a stator part (44) connected to the casing and having plural statoric airfoils (55) and a rotor part (50) configured to rotate relative to the stator part and having plural rotoric airfoils (54). The axial multistage expander (40) also includes a support mechanism (48) connected to the casing and configured to rotatably support the rotor part. Rotoric airfoils of at least one stage of the plurality of stages are configured to rotate with a speed different from rotoric airfoils of the other stages. An epicyclic gearbox (52) is connected between the at least one stage and the turbine shaft (50). The stator part, the rotor part and the support mechanism of the plurality of stages are provided inside the casing. The axial multistage expander may be used within a thermal energy storage (120) and gas storage (122) cycle (110).