Cryogenic Pump Inducer Blade Root Thickening
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In inducers used in cryogenic fluid pumps, increasing blade thickness to enhance bending strength leads to a narrower flow path, accelerating cavitation and reducing suction performance due to increased wedge surface angles.
Innovation Solution
A design where the blade thickness is increased in the root portion on the positive-pressure surface without altering the wedge surface angle on the negative-pressure surface, maintaining suction performance by adjusting the shape on the positive-pressure surface side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the blade thickness of the root portion is increased to increase bending strength, then the bending strength of the blade is improved, but the angle of the wedge surface increases which causes cavitation performance to decrease and suction performance to deteriorate
Solution Approach 1:
The patent applies local quality by differentiating the blade thickness distribution between the positive-pressure surface and negative-pressure surface. Specifically, the blade thickness is increased at the root portion on the positive-pressure surface while maintaining the original thickness profile on the negative-pressure surface. This localized modification allows the blade to gain bending strength without altering the wedge surface angle that governs cavitation performance, thereby resolving the contradiction between structural strength and hydraulic performance.
2Strength
If the angle of the wedge surface increases due to increased blade thickness, then the bending strength is improved, but the flow path width between blades is narrowed which accelerates clogging and reduces suction performance
Solution Approach 1:
The invention implements local quality by selectively increasing blade thickness only on the positive-pressure surface at the root portion, while keeping the negative-pressure surface geometry unchanged. This ensures that the flow path width between blades remains adequate for preventing clogging, while the localized thickening provides the necessary bending strength. The wedge surface angle on the negative-pressure surface is preserved, maintaining proper flow path dimensions.
Data Source
AI summary
An inducer includes a hub and a blade which radially protrudes from the hub and is helically provided. The inducer has a thick portion in which a first distance and a second distance coincides with each other in a region outside a position at which a height ratio of the blade is 0.5 while the first distance is shorter than the second distance in a region inside the position at which the height ratio of the blade is 0.5, in which the height ratio is a ratio of a distance from a connection portion between the hub and a root portion of the blade with respect to a height of the blade which is a distance from the connection portion between the hub and the root portion of the blade to a tip portion of the blade in the radial direction of the blade.