Variable Span Splitter Blade for Gas Turbine Compressor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Flow separation within the flow passage of a gas turbine engine compressor stage occurs due to adverse pressure gradients, leading to inefficient entropy-generating recirculation zones, which decrease the overall efficiency of the compressor.
Innovation Solution
The introduction of a variable spanwise clearance along the chord length of the splitter blade allows higher-energy flow from the pressure side to spill over into the low-energy suction side, delaying and minimizing recirculation zones, thereby re-energizing the flow and reducing entropy generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the blade count of the main blades is increased to prevent flow separation, then the efficiency of the compressor stage is improved, but the device complexity and weight increase
Solution Approach 1:
The splitter blade is segmented into two distinct portions: a first portion extending from the hub to a first radius, and a second portion extending from the hub to a second radius that is less than the first radius. This segmentation creates a variable span configuration where the blade clearance varies along the span, allowing optimization of flow control without increasing overall blade count
Solution Approach 2:
Different portions of the splitter blade are given different span lengths, creating local variations in blade characteristics. The first portion has a different radius than the second portion, allowing each section to be optimized for its specific flow conditions while maintaining overall system efficiency
2Productivity
If the splitter blade span is increased to reduce flow separation, then the efficiency is improved, but the weight and material usage increase
Solution Approach 1:
The splitter blade is divided into two span portions with different radii, allowing the blade to be present only where flow control is needed. The second portion extends to a smaller radius than the first portion, eliminating unnecessary blade material in regions where it would not provide benefit
Solution Approach 2:
Instead of extending the splitter blade through the entire span, the invention uses a partial span configuration where the second portion terminates at a smaller radius. This partial action provides sufficient flow control to prevent separation while minimizing the amount of blade material required
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 approach increases the efficiency of the compressor stage by reducing flow separation and entropy generation, enhancing structural reliability, and decreasing weight and material usage by optimizing the splitter blade's position and size.
Implementation Method 1
By making a spanwise cut along the chord length of the splitter blade (variable blade clearance from leading edge to trailing edge), additional secondary flow occurs within the flow passages as the higher pressure flow on the pressure side of the blade can now spill over into the low-pressure suction side of the blade
Implementation Method 2
flow separation still occurs within the flow passage due to an adverse pressure gradient: the flow is slowed down with increasing streamwise distance to the point of stopping, followed by flow reversal, separation and recirculation
Data Source
AI summary
The presently disclosed embodiments utilize flow from a higher-energy portion of flow within the impeller flow path and inject it into the lower-energy portion of the flow path to re-energize the flow, delaying the onset of, or minimizing, large (and inefficient, entropy-generating) re-circulation zones in the flow field. By making a spanwise cut along the chord length of the splitter blade (variable blade clearance from leading edge to trailing edge), additional secondary flow occurs within the flow passages as the higher pressure flow on the pressure side of the blade can now spill over into the low-pressure suction side of the blade.