Critical Flow Nozzle Fuel Distribution for Gas Turbine Stability
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Solution Overview
Problem
Current fuel delivery systems for gas turbine engines are complex, expensive, and heavy, requiring intricate control systems, and fail to efficiently manage fuel flow to prevent undesirable rotating pressure waves during low flow conditions.
Innovation Solution
A fuel delivery system incorporating fixed and variable critical flow nozzles, where the fixed nozzle operates at choked flow with a fixed orifice throat and the variable nozzle adjusts its effective cross-sectional area based on fuel pressure using a spring-biased piston and needle, ensuring equal or unequal fuel distribution to combustor quadrants depending on operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current fuel delivery systems are used, then fuel can be delivered to the gas turbine engine, but the system becomes expensive, heavy, and complex requiring intricate control systems
Solution Approach 1:
The fuel delivery system uses self-regulating critical flow nozzles that automatically adjust fuel flow based on pressure differential without requiring external control systems. The nozzles self-regulate by their physical design, eliminating complex control mechanisms while maintaining reliable fuel delivery.
Solution Approach 2:
The patent replaces complex mechanical control systems with a physics-based flow regulation mechanism. The critical flow nozzles use pressure differential and fluid dynamics to automatically control fuel flow, substituting intricate mechanical control with a simpler physical principle.
2Object-affected harmful factors
If unequal fuel flow is provided to fuel nozzles during low flow operations, then some quadrants of the combustor can be at higher pressure than others preventing rotating pressure waves, but the system becomes complex requiring flow divider circuitry
Solution Approach 1:
The fuel delivery system is segmented into multiple independent critical flow nozzles, each capable of regulating its own flow. This segmentation allows unequal fuel distribution to different combustor quadrants without requiring complex centralized flow divider circuitry.
Solution Approach 2:
The system changes the flow regulation parameter from complex mechanical flow division to pressure differential-based flow control. By adjusting the pressure differential across each nozzle, the system achieves unequal fuel distribution to prevent rotating pressure waves without complex circuitry.
3Productivity
If a cavitating venturi is used at a fuel nozzle to adjust flow rate, then flow rate can be controlled, but the system remains complex and expensive
Solution Approach 1:
The patent uses critical flow nozzles that regulate flow rate by changing the pressure differential parameter across the nozzle. This approach controls flow rate efficiently while avoiding the complexity of cavitating venturis by using a simpler geometric design.
Solution Approach 2:
The invention extracts the flow control function from complex systems like cavitating venturis and implements it through simple critical flow nozzles. By taking out the essential flow regulation capability and implementing it through a simpler mechanism, the system achieves the same productivity with reduced complexity.
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 precise fuel flow management, preventing engine howling and hot spots, reducing engine wear, and eliminating the need for complex control systems by automatically adjusting fuel distribution based on pressure, thereby enhancing engine performance and longevity.
Implementation Method 1
a needle mounted on a spring biased piston, the needle positionable in the orifice throat to adjust the effective cross-sectional area of the orifice throat based upon a fuel pressure at the inlet
Implementation Method 2
adjust the effective cross-sectional area of the orifice throat based upon a fuel pressure at the inlet
Implementation Method 3
fixed critical flow nozzle has an orifice throat with a fixed effective cross-sectional area
Implementation Method 4
A cavitating venturi can be used at a fuel nozzle of the fuel delivery system to adjust the flow rate through the fuel delivery system
Implementation Method 5
a nozzle having a converging-diverging shape and including the orifice throat and a recovery section downstream of the orifice throat
Data Source
Figure 1
Figure 2~3B
Figure 4A~5B
AI summary
A fuel delivery system (10) for delivering fuel to a gas turbine engine includes a fixed critical flow nozzle (22), a variable critical flow nozzle (24), a first fuel nozzle (36) and a second fuel nozzle (38). The fixed critical flow nozzle (22) and the variable critical flow nozzle (24) are connected to a fuel source (14) in parallel. The fixed critical flow nozzle has an orifice throat (42) with a fixed effective cross-sectional area. The variable critical flow nozzle has an orifice throat (58) with a variable effective cross-sectional area. The first fuel nozzle (36) is connected to the fixed critical flow nozzle (22) for delivering fuel to the gas turbine engine, and the second fuel nozzle (38) is connected to the variable critical flow nozzle (24) for delivering fuel to the gas turbine engine.