Passive Split Flow Divider Valve for Turbine Fuel Distribution
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Solution Overview
Problem
Existing split fuel flow distribution systems for turbine engines face challenges in efficiently managing fuel flow between primary and secondary manifolds during low power and high power operating conditions, requiring different split ratios and purging strategies without increasing complexity or cost through passive means.
Innovation Solution
A passive split flow divider valve system utilizing a primary piston and secondary piston, with an ecology valve and transfer valve, allows for different fuel split ratios based on combustion fuel flow direction, enabling fuel supply to both manifolds during high power and only to the primary manifold during low power, while maintaining a consistent overall fuel flow rate and purging the secondary manifold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple flow divider valve is used to control fuel flow to primary and secondary manifolds, then the system structure is simple and cost is reduced, but the system cannot provide different split ratios for low power and high power operating conditions
Solution Approach 1:
The flow divider valve is segmented into two independent pistons (primary piston and secondary piston) that can move independently of each other. This segmentation allows each piston to control its respective manifold separately, enabling different split ratios for low power and high power operating conditions without requiring a completely different valve structure for each mode.
Solution Approach 2:
The valve system transitions from a static single-piston design to a dynamic two-piston system where the pistons can move independently based on operating conditions. The primary piston responds to primary manifold pressure while the secondary piston responds to secondary manifold pressure, allowing the system to adapt dynamically between different operating modes (low power vs. high power) without increasing overall system complexity.
2Reliability
If the secondary manifold is purged during low power operation, then flame out margin is improved and nozzle coking is prevented, but fuel flow to the engine is reduced
Solution Approach 1:
The fuel flow control is segmented into independent primary and secondary pathways controlled by separate pistons. During low power operation, the secondary piston can close the secondary manifold to purge it and prevent coking, while the primary piston maintains fuel flow to the primary manifold. This segmentation allows the system to maintain total fuel flow while selectively purging the secondary manifold.
Solution Approach 2:
Different quality of fuel flow is provided to different manifolds based on operating conditions. During low power operation, the primary manifold receives fuel flow while the secondary manifold is purged. The system locally optimizes the fuel flow quality for each manifold according to its specific operational needs, ensuring flame out margin while maintaining overall fuel flow.
3Adaptability or versatility
If computer driven control is used to enable different fuel flow modes, then operating flexibility is improved, but system complexity and cost increase
Solution Approach 1:
The flow divider valve system is designed to be self-regulating through the independent movement of primary and secondary pistons driven by manifold pressures. The system automatically adapts to different operating conditions (low power vs. high power) based on pressure differentials without requiring external computer control. This self-service approach maintains operating flexibility while minimizing control system complexity and cost.
Solution Approach 2:
The patent replaces computer-driven electronic control with a purely mechanical piston-based control system. The primary and secondary pistons respond automatically to pressure differentials in their respective manifolds, eliminating the need for sensors, actuators, and control algorithms. This mechanical substitution maintains operating mode flexibility while significantly reducing system complexity and cost.
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
The system achieves efficient fuel distribution with reduced complexity and cost, ensuring reliable operation by maintaining flame out margin and preventing nozzle coking during extended low power periods.
Implementation Method 1
As the fuel pressure from the fuel control system is reduced from the primary operating condition shown on the left of FIG. 6, the reduced fuel pressure allows the main split flow control piston to move upward under force of the main control spring
Implementation Method 2
The primary piston strokes with increasing fuel pressure to meter such flow to the primary manifold
Implementation Method 3
the ecology piston is held on an ecology valve seat by a secondary spring during the operating modes. However, once the shutdown mode is achieved by full stroke of the main split flow control piston, the ecology piston is lifted from its seat to drain the primary and secondary manifolds
Data Source
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AI summary
A passive flow splitting system for use in a turbine engine control system to provide split fuel flow to two fuel manifolds to supply primary and secondary fuel injectors for the particular combustion zones thereof utilizing intentionally different split ratios dependent on ascending or descending combustion fuel flow is provided. The system includes a passive fuel divider valve (FDV) that includes a primary piston and a secondary piston. The primary piston is moveable independently from the secondary piston during a portion of its stroke, and is hydro-locked to the secondary piston during another portion of its stroke. An ecology valve is also provided to purge the fuel from the primary and/or secondary manifolds during different modes of operation. A transfer valve is included to control the position of ecology piston of the ecology valve.