Roller-Shaped Runner Diameter-to-Length Ratio Optimization
Solution Overview
Problem
Existing roller-shaped impellers in flow-through turbines face limitations in adaptability due to a fixed diameter-to-length ratio, leading to reduced service life and mechanical stress when trying to increase length, which is critical for new application requirements such as energy recovery in paper production.
Innovation Solution
A roller-shaped impeller design with a shaft and end/intermediate disks having radial slots for profiled blades, where the outer diameter to length ratio is optimized between 0.08 and 0.25, and blades are stiffened with increased thickness and weld seams strategically placed to reduce mechanical stress and enhance torsional rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the length of the cylindrical impeller is increased to meet new application requirements, then the adaptability to new areas of application is improved, but the axial deflection becomes critical and the service life is reduced
Solution Approach 1:
The invention changes the geometric parameters of the impeller by optimizing the diameter-to-length ratio to a specific range (0.08 ≤ D/L ≤ 0.25), which allows the impeller to achieve greater lengths while maintaining structural integrity and avoiding critical axial deflection, thus extending service life while improving adaptability
Solution Approach 2:
The invention introduces adjustable pitch angles for the profiled blades (α between 10° and 30°, β between 10° and 30°) that can be optimized based on specific application requirements, allowing the impeller to adapt to different operating conditions while maintaining mechanical stability through proper geometric configuration
2Adaptability or versatility
If the length of the cylindrical impeller is increased, then the adaptability to new areas of application is improved, but the connection between the shaft and the blade assembly cannot withstand the mechanical stresses
Solution Approach 1:
The invention optimizes the diameter-to-length ratio parameter to ensure that even at increased lengths, the mechanical stresses remain within acceptable limits for the connection between the shaft and blade assembly, preventing failure while enabling extended impeller lengths for new applications
Solution Approach 2:
The invention applies specific geometric optimizations locally at critical connection points, including the configuration of profiled blades with optimized pitch angles and the structural design of the blade assembly connection to the shaft, ensuring these local areas can withstand the mechanical stresses generated during operation
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 allows for longer impeller lengths with improved mechanical stability and reduced deflection, enabling safe operation and increased service life, particularly for applications like energy recovery in paper production.
Implementation Method 1
cross-flow turbines and their construction have been known in the art for some time... the cylindrical runner of a cross-flow turbine is first subjected to flow from the outside in. After the water has passed through the interior of the cylindrical runner, it exits from the inside out. In this way, the cylindrical runner is rotated
Implementation Method 2
the profiled blades of the cylindrical impeller are fixed in these slots, so that they form a ring of profiled blades within the impeller
Data Source
Figure 1
Figure 2
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AI summary
The present invention relates to a roller-shaped runner (20) of a cross-flow turbine (1) through which a flow can pass radially from outside to inside and then radially from inside to outside. The runner (20) has a shaft (22) with at least two end disks (40) arranged on the shaft (22) at the ends and a plurality of intermediate disks (30) that are secured to the shaft (22) between the end disks (40). The end disks (40) and the intermediate disks (30) define radial planes relative to the shaft (22). Furthermore, the end disks and intermediate disks (30) each have a plurality of radially outwardly arranged slots (32) in which is secured, in each case in one slot (32) of two end disks and multiple intermediate disks (30), a profiled blade (50) running parallel to the shaft (22), so that the shaft (22) is surrounded, at a radial distance, by a ring of profiled blades (50). The roller-shaped runner (20) has an outer diameter D and a length L, where 0.08<D/L<0.25.