Variable Speed Fuel Pump Controller for Turbomachine Light-Off
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Solution Overview
Problem
Existing fuel delivery systems for turbomachines face challenges in achieving light-off due to variations in fuel delivery rates caused by production tolerances, fuel types, and environmental conditions, requiring complex and costly arrangements of pressure sensors and metering valves to compensate for these differences.
Innovation Solution
A fuel delivery system with a variable speed motor-driven fuel pump and a controller that adjusts fuel flow rates from an initial low setting to a higher setting, using a solenoid and flow divider valve to ensure optimal fuel delivery to the combustor, allowing for gradual increase in fuel flow to achieve light-off without flooding the combustor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex pressure sensors and metering valves are used to compensate for fuel delivery variations, then light-off reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent removes complex pressure sensors and metering valves from the fuel delivery system, retaining only essential components. The controller directly commands fuel pump flow rates without intermediate sensing or metering devices, simplifying the system while maintaining light-off reliability through direct electronic control of the variable speed fuel pump.
Solution Approach 2:
The patent replaces mechanical pressure sensors and metering valves with an electronically controlled variable speed fuel pump. The controller uses electronic signals to directly adjust pump speed and fuel flow rate, substituting mechanical compensation mechanisms with electronic control that achieves the same reliability without the complexity of additional mechanical components.
2Reliability
If fuel delivery rate is increased to ensure light-off, then light-off achievement is improved, but fuel consumption increases
Solution Approach 1:
The patent uses a variable speed fuel pump that dynamically adjusts fuel delivery rate based on real-time engine conditions and startup progress. The controller modulates pump speed to deliver the precise fuel flow rate needed for light-off, avoiding excessive fuel delivery while ensuring reliable ignition. This dynamic control allows the system to use only the necessary amount of fuel rather than delivering a fixed high rate.
Solution Approach 2:
The patent changes the fuel delivery parameter from a fixed high flow rate to a variable flow rate controlled by pump speed. The controller adjusts the fuel pump's rotational speed to match the exact fuel quantity required for light-off under different operating conditions, optimizing fuel consumption while ensuring reliable light-off achievement.
3Device complexity
If fixed fuel delivery rate is used during startup, then system simplicity is maintained, but adaptability to different conditions deteriorates
Solution Approach 1:
The patent implements a variable speed fuel pump that can dynamically adjust its delivery rate during startup operations. This dynamic capability allows the system to adapt to different fuel types, temperatures, and altitude conditions without adding complex mechanical components. The controller modifies pump speed in real-time to optimize fuel delivery for each specific operating condition.
Solution Approach 2:
The variable speed fuel pump serves multiple functions: it delivers fuel at different rates for various startup conditions, compensates for environmental variations, and ensures reliable light-off across different fuel types. This single multi-functional component replaces what would otherwise require multiple specialized components, maintaining system simplicity while achieving broad adaptability.
Data Source
AI summary
An example method of fuel delivery to a turbomachine includes reaching a light-off speed of a turbomachine and delivering fuel to a combustor of the turbomachine at a first rate. The method also increases the rate of the delivery. The combustor achieves light-off at a fuel flow rate on or in-between the first rate and a second rate that is greater than the first rate. An example turbomachine fuel delivery assembly includes a fuel delivery component and a controller configured to adjust the fuel pump to increase a rate of fuel delivery from a fuel supply to a combustor of a turbomachine.