Turbine Fuel Injection Thermal Protection Screen
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Solution Overview
Problem
The intermittent operation of multipoint fuel injection systems in turbine engines leads to coking and reduced fuel spraying due to high temperatures from combustion chamber radiation, causing operational issues and potential plugging of injection orifices.
Innovation Solution
A thermal protection screen formed by a downstream annular separation wall with a larger diameter than the injection orifices, combined with an internal air cavity and air-passing orifices to control fuel flows and separate combustion zones, reducing temperature rise and improving atomization and evaporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the multipoint circuit operates intermittently to optimize fuel delivery for high speeds, then fuel spraying efficiency is improved, but the stagnant fuel inside the circuit is exposed to high temperatures from combustion chamber radiation, causing coking and orifice plugging
Solution Approach 1:
The patent introduces a thermal protection screen as an intermediary element positioned between the combustion chamber radiation and the multipoint circuit. This screen acts as a mediator that blocks harmful thermal radiation while allowing the multipoint circuit to maintain its intermittent operation mode for optimized fuel spraying at high speeds, thereby preventing coking without compromising spraying efficiency
Solution Approach 2:
The patent converts the harmful effect of thermal radiation into a beneficial protective function by positioning the thermal protection screen to utilize the radiation barrier effect. The screen transforms the potentially harmful high-temperature environment into a controlled thermal zone that protects the multipoint circuit components, allowing intermittent operation without coking while maintaining spraying performance
2Object-affected harmful factors
If the separation wall is extended downstream to improve combustion zone separation, then pilot and multipoint combustion zones are better separated, but the separation wall becomes more exposed to high temperatures, increasing thermal stress and potential damage
Solution Approach 1:
The patent introduces a thermal protection screen as an intermediary element that positions itself between the high-temperature combustion chamber environment and the separation wall. This screen mediates the thermal exposure, allowing the separation wall to maintain its downstream extension for effective combustion zone separation while being protected from excessive thermal stress and potential damage
Solution Approach 2:
The patent applies beforehand cushioning by pre-positioning the thermal protection screen upstream of the separation wall to shield it from high-temperature radiation before the heat can affect the wall. This protective barrier is installed in advance to cushion the separation wall against thermal shock and sustained high-temperature exposure, enabling extended downstream positioning for better combustion separation
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 effectively prevents coking, enhances fuel combustion, reduces polluting emissions, and maintains the integrity of the separation wall by cooling it and improving the separation between pilot and multipoint combustion zones.
Implementation Method 1
the separation wall forms a thermal protection screen for these orifices against the heat radiation coming from the combustion chamber
Implementation Method 2
a pilot injector is mounted, the pilot injector being centered on the axis of the venturi
Data Source
AI summary
A fuel injection device is provided. The device includes a pilot injector opening out into a venturi and an annular row of multipoint injection orifices opening out axially in a downstream direction and radially outside the venturi, the venturi being connected at its downstream end to a separation wall. The outer peripheral edge of the separation wall has a diameter greater than the diameter of the annular row of injection orifices, whereby the separation wall forms a thermal protection screen for these orifices against heat radiation coming from the chamber.