Variable Drive Fuel Pump for Gas Turbine Engine
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fuel delivery systems for gas turbine engines face challenges in optimizing fuel pump sizing due to opposing sizing requirements for high engine power conditions and low engine shaft speed conditions, leading to inefficient fuel flow and undesirable design consequences.
Innovation Solution
A continuously variable drive assembly is introduced, connecting the gearbox of a gas turbine engine to the fuel pump, with a governor controlling the drive ratio to adjust fuel pump flow performance across various engine operating conditions. This system ensures the fuel pump is sized to meet demand in specific conditions, such as take-off mode, while optimizing performance in start and cruise modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a positive displacement pump is sized for high engine power conditions such as take-off, then fuel flow demand at high power is met, but fuel flow is insufficient at engine start and low shaft speed
Solution Approach 1:
The patent applies a continuously variable transmission (CVT) mechanism with variable pulleys that dynamically adjust the drive ratio between the gearbox and fuel pump. This allows the fuel pump speed to be varied continuously across different operating conditions, enabling a single pump size to deliver appropriate fuel flow for both high power take-off conditions and low power start conditions, thus resolving the contradiction between meeting high fuel flow demand and adapting to varying operating conditions.
2Quantity of substance
If fuel pumps are sized only for engine start conditions, then fuel flow at low shaft speed is sufficient, but excess fuel pumping capability occurs at high engine shaft speeds
Solution Approach 1:
The CVT mechanism dynamically adjusts the drive ratio to match fuel pump output to actual engine fuel flow demand. During engine start conditions, the variable pulleys increase the drive ratio to provide sufficient fuel flow. During high shaft speed cruise conditions, the pulleys reduce the drive ratio to prevent excess fuel pumping capability, thereby eliminating energy waste while maintaining adequate fuel supply during critical start operations.
3Quantity of substance
If larger or oversized fuel pump volumes are used, then fuel flow capacity is increased, but system integrity, weight, envelope and thermal management are negatively impacted
Solution Approach 1:
Instead of using a larger fixed-volume fuel pump to ensure sufficient fuel flow capacity across all conditions, the patent employs a CVT mechanism that dynamically adjusts the effective pump capacity through variable speed control. This allows a smaller, optimally-sized pump to deliver high fuel flow capacity when needed during take-off by increasing pump speed via the variable pulley system, rather than relying on physical pump size, thus reducing weight while maintaining required fuel flow capacity.
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 solution enables an optimized fuel pump package with minimal operational volume, size, and weight, while ensuring precise fuel flow management and improved thermal efficiency, facilitating easier engine re-start and enhanced overall power thermal management.
Implementation Method 1
a drive belt operatively connecting the driving pulley assembly to the driven pulley assembly
Implementation Method 2
a governor for controlling a drive ratio of the drive assembly to vary fuel pump flow performance over a range of engine operating conditions
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A fuel delivery system for a gas turbine engine (12) is disclosed which includes a continuously variable drive assembly (14) having a driving portion operatively associated with a gearbox (18) of the gas turbine and a driven portion operatively associated with a fuel pump (22) of the gas turbine, and a governor for controlling a drive ratio of the drive assembly (14) to vary fuel pump flow performance over a range of engine operating conditions.