Gas Turbine Compressor Stator Vane Angle Retrofit
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Solution Overview
Problem
Gas turbine engines experience sub-optimum operating characteristics and reduced power output when operating at hotter ambient conditions, as the aerodynamic inlet corrected speed decreases, causing front compressor stages to operate near stall and rear stages to operate near choke, leading to inefficient performance.
Innovation Solution
The method involves retrofitting the gas turbine engine by replacing selected stator bladerows with improved ones having a smaller stator vane angle, which increases the inlet swirl angle, resulting in enhanced pressure ratio and flow rate, achieved by modifying the stator vane assembly with a cylindrical surface and perforations to accommodate stator vanes with a reduced angle, optimizing compressor performance during hot day conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the gas turbine engine operates at hotter ambient conditions, then the engine continues to operate, but the aerodynamic inlet corrected speed decreases to design speed, causing front compressor stages to operate near stall and rear stages near choke, resulting in sub-optimum operating characteristics and reduced power output
Solution Approach 1:
The patent changes the geometric parameters of the stator vanes by reducing the stator vane angle from a first angle to a second, smaller angle. This parameter change modifies the inlet swirl angle and flow characteristics, allowing the compressor to maintain optimal operating characteristics at higher ambient temperatures, thereby resolving the contradiction between temperature and power output
2Temperature
If the gas turbine engine operates at hotter ambient conditions, then the engine continues to operate, but the aerodynamic inlet corrected speed decreases, causing front compressor stages to operate closer to the stall side, resulting in reduced compressor efficiency
Solution Approach 1:
By changing the stator vane angle parameter to a smaller second angle, the patent modifies the flow angles and inlet swirl to move the compressor operating point away from the stall side toward the peak efficiency region of the compressor map, thereby improving reliability and operability at high ambient temperatures
3Temperature
If the gas turbine engine operates at hotter ambient conditions, then the engine continues to operate, but the rear compressor stages are forced to operate closer to the choke side, resulting in reduced flow rate and pressure ratio
Solution Approach 1:
The reduction in stator vane angle to a second, smaller angle increases the inlet swirl angle, which modifies the flow characteristics through the compressor stages. This parameter change increases the flow rate and pressure ratio by optimizing the aerodynamic path, allowing the rear stages to operate further from the choke side even at high ambient temperatures
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 solution improves the overall compressor efficiency, flow rate, and surge margin by adjusting the stator vane angle, allowing the gas turbine engine to operate more effectively at higher ambient temperatures and lower corrected speeds, increasing power output and pressure ratio while maintaining robust operability.
Implementation Method 1
The first improved stator bladerow can have a second inlet swirl angle less than the first inlet swirl angle to produce an increased pressure ratio and increased flow rate
Data Source
AI summary
A method and device for retrofitting a gas turbine engine for improved hot day performance are disclosed. The method can include removing a first selected stator bladerow from the plurality of compressor stages, the first selected stator bladerow having a first inlet swirl angle and including a first plurality of fixed stator vanes. Each stator vane of the first plurality of fixed stator vanes can have a first stator vane angle. The method can also include providing a first improved stator bladerow to replace the first selected stator bladerow. The first improved stator bladerow can have a second plurality of fixed stator vanes, each having a second stator vane angle smaller than the first stator vane angle. The method can also include replacing the first selected stator bladerow with the first improved stator bladerow to produce an increased pressure ratio and flow rate compared to the first selected stator bladerow.