Gas Turbine Compressor Stage Throttling Factor Optimization
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Solution Overview
Problem
Conventional compressor stages for gas turbines are limited by a throttling factor σ less than 5.16 minus 1.33 times the aspect ratio ARax, which restricts their efficiency and length, making it challenging to reduce fuel consumption while maintaining aerodynamic and mechanical loads.
Innovation Solution
Designing compressor stages with a throttle coefficient σ greater than -1.33 times the aspect ratio ARax, incorporating a rotor cascade and vane cascade with specific geometric and aerodynamic configurations, allowing for increased efficiency and reduced length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional compressor stages are designed with throttling factor σ ≤ 5.16 - 1.33·ARax, then aerodynamic stability is maintained, but compressor length and weight are excessive and efficiency is limited
Solution Approach 1:
The invention changes the fundamental design parameter relationship by allowing σ > 5.16 - 1.33·ARax, breaking the conventional design limit. This parameter change enables higher aerodynamic loading per stage, which directly increases compressor efficiency while reducing the number of stages and overall compressor length required to achieve the same pressure ratio.
Solution Approach 2:
The invention incorporates preliminary action through optimized pre-swirl vanes and carefully designed inlet guide vanes that condition the airflow before it enters the rotor blades. This preliminary flow conditioning allows the compressor stage to operate at higher throttling factors without sacrificing aerodynamic stability, enabling both improved efficiency and reduced length.
2Use of energy by moving object
If compressor stages are designed to reduce fuel consumption, then geometric size is reduced, but maintaining aerodynamic load capacity becomes challenging
Solution Approach 1:
By changing the acceptable range of the throttling factor parameter beyond conventional limits, the invention achieves higher aerodynamic load capacity in a smaller geometric configuration. This parameter change allows the compressor to process more air mass per unit volume, directly improving power density while reducing overall engine size and fuel consumption.
Solution Approach 2:
The invention employs composite aerodynamic designs combining different blade profiles, pre-swirl vane configurations, and flow control features within the same compressor stage. This composite approach optimizes the balance between aerodynamic loading and geometric size, enabling high power capacity in a compact form factor that reduces fuel consumption.
3Length of stationary object
If compressor stages operate at higher throttling factors, then compressor length is reduced, but aerodynamic stability may be compromised
Solution Approach 1:
The pre-swirl vanes and inlet guide vanes perform preliminary flow conditioning that prepares the airflow for high-throttling-factor operation. This preliminary action ensures smooth flow entry onto the rotor blades, preventing flow separation and stall even at elevated throttling factors, thereby maintaining aerodynamic stability in a compact compressor design.
Solution Approach 2:
The invention introduces intermediary flow control elements (pre-swirl vanes, inlet guide vanes) that mediate between the high-throttling-factor operating condition and the rotor blades. These intermediaries condition the flow to prevent direct adverse interactions that would cause instability, enabling high power density without sacrificing reliability.
Data Source
Figure 1~2
AI summary
The present invention relates to a compressor stage for a gas turbine, in particular of an aircraft engine, comprising a grid (3) and a guide grid (4), in particular adjacent downstream, wherein the throttle factor σ and the aspect ratio ARax defined by the quotient of mean channel height (h) and mean chord length (lax) satisfy the condition σ>-1.33⋅ARax+5.16.