Fuel Divider Piston Dynamics for Gas Turbine Engine Flow Control
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Solution Overview
Problem
Conventional fuel divider systems for gas turbine engines bias up fuel flow to atomizer nozzles during start-up but also during low flow post-start-up conditions like flight idle, leading to uneven fuel distribution and potential engine distress, and allow premature ecology valve movement during start-up, disrupting scheduled fuel distribution.
Innovation Solution
A fuel divider system with a movable FD piston and a closed-loop hydromechanical design that biases fuel flow to atomizer nozzles during start-up and equalizes it with air blast nozzles during low flow conditions, preventing ecology valve movement during start-up to maintain optimal fuel distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fuel divider systems bias up fuel flow to atomizer nozzles during start-up, then optimal engine lightoff conditions are achieved, but uneven fuel distribution occurs during low flow post-start-up conditions like flight idle
Solution Approach 1:
The fuel divider system employs a movable piston that dynamically adjusts fuel flow distribution based on real-time fuel pressure conditions. During start-up, the piston positions to bias flow to atomizer nozzles for optimal lightoff. During low flow post-start-up conditions, the piston shifts to equalize flow between atomizer and air blast nozzles, preventing uneven spray patterns and heat-induced combustor distress.
Solution Approach 2:
The system changes the fuel flow distribution parameter by utilizing fuel pressure differentials to move the piston between distinct positions. The piston responds to changes in fuel pressure caused by varying fuel flow rates, automatically adjusting the flow split ratio between atomizer and air blast nozzles to match operational requirements.
2Productivity
If conventional fuel divider systems allow ecology valve movement during start-up, then fuel is reintroduced to the manifold, but scheduled fuel distribution is altered and ideal start flow conditions are compromised
Solution Approach 1:
The fuel divider piston acts as an intermediary control element between the fuel supply and the nozzles. During start-up, the piston remains in a position that maintains proper fuel distribution to atomizer and air blast nozzles, effectively mediating to prevent premature ecology valve operation and preserve ideal start flow conditions.
Solution Approach 2:
The system takes preliminary action by positioning the piston to counteract or prevent premature ecology valve movement during start-up. The piston's positioning creates fuel pressure conditions that inhibit premature valve operation, thereby protecting the start-up process from disruption before any harmful effect can occur.
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 ensures optimal fuel distribution during engine start-up and low flow conditions, preventing engine distress and maintaining scheduled fuel flow patterns by preventing ecology valve movement and using a closed-loop hydromechanical design to eliminate the need for external controllers.
Implementation Method 1
An FD control chamber is fluidly coupled to the flow passage network and fluidly communicates with the FD piston. At least one channel is provided through the FD piston and configured to cooperate with the flow passage network to port the FD control chamber to: (i) the fuel pressure at the secondary outlet when the FD piston is in the flow biasing position, and (ii) the fuel pressure within the inlet chamber when the FD piston is in the flow equalizing position.
Data Source
AI summary
A fuel divider system includes a housing assembly and a flow passage network having an inlet, a primary outlet, and a secondary outlet. A fuel divider piston is slidably disposed within the housing assembly and movable between a flow biasing position and a flow equalizing position. A control chamber is fluidly coupled to the flow passage network and fluidly communicates with the piston. An inlet chamber, at least partially defined by the piston and the housing assembly, is fluidly coupled to the inlet. At least one channel is provided through the piston and configured to cooperate with the flow passage network to port the FD control chamber to: (i) the fuel pressure at the secondary outlet when the FD piston is in the flow biasing position, and (ii) the fuel pressure within the inlet chamber when the FD piston is in the flow equalizing position.