Bimodal Rocket Igniter Switching for Pressure Regimes
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Solution Overview
Problem
Current rocket engine igniters are limited to single operating points, either low or high pressure, making them ineffective in varying conditions, such as on the ground or in flight, and are either inefficient or excessively heavy and costly due to separate pressurized propellant tanks.
Innovation Solution
A bimodal igniter system that includes a first and second propellant supply, a high-pressure fluid, and buffer tanks with switching devices to adapt to low and high pressure regimes, using a high-pressure fluid to overcome counter-pressure and ensure ignition in both conditions without separate heavy tanks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a low-pressure igniter is used, then the igniter is lightweight and simple, but it cannot overcome counter-pressure in the combustion chamber on the ground or at low altitude
Solution Approach 1:
The igniter system dynamically switches between low-pressure and high-pressure modes based on operating conditions. A switching device directs the high-pressure fluid to the buffer tank when counter-pressure is detected, enabling the system to adapt its pressure output dynamically rather than operating at a fixed pressure level
Solution Approach 2:
A high-pressure fluid acts as an intermediary substance that is injected into the buffer tank to temporarily pressurize the propellant. This intermediary high-pressure fluid allows the system to overcome counter-pressure conditions without requiring permanently heavy high-pressure propellant storage tanks
2Reliability
If a high-pressure igniter with separate pressurized propellant tanks is used, then ignition reliability under counter-pressure is improved, but the system becomes heavy and expensive
Solution Approach 1:
The buffer tank serves multiple functions: it stores propellant for low-pressure operation, receives high-pressure fluid injection for high-pressure operation, and acts as a mixing chamber. This multi-functionality eliminates the need for separate high-pressure propellant storage tanks, significantly reducing system weight and cost
Solution Approach 2:
The system changes the pressure parameter of the propellant delivery by injecting high-pressure fluid into the buffer tank. This temporary parameter change allows the propellant to be delivered at high pressure only when needed to overcome counter-pressure, rather than maintaining high pressure continuously
3Device complexity
If a single operating point igniter is used, then the device complexity is reduced, but the igniter cannot adapt to varying operating conditions such as ground level or high altitude
Solution Approach 1:
The switching device enables dynamic adaptation between low-pressure and high-pressure modes based on the operating conditions. The system monitors the need for high-pressure operation and activates the high-pressure fluid injection accordingly, allowing a single igniter structure to adapt to varying pressure regimes without requiring multiple dedicated igniters
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
Enables reliable ignition in both low and high pressure environments with a single compact architecture, reducing the need for heavy pressurized tanks and ensuring consistent engine startup, while maintaining a stable combustion ratio for efficient operation.
Implementation Method 1
a high pressure fluid is used which is injected into the buffer tank following the propellant which was previously present there to pressurize the latter and push it into the combustion chamber of the fuel igniter
Implementation Method 2
fitted with a spark plug capable of igniting the small quantity of propellant supplied: the flames thus generated are then channeled in the form of a torch towards the combustion chamber engine combustion
Implementation Method 3
the propellants flow from their supply tanks where they are stored at low pressure, cross their respective buffer tank, and flow into the combustion chamber of the igniter where they mix
Data Source
Figure 1
Figure 2
AI summary
The present invention relates to a bimodal igniter and to a bimodal injection method for an igniter that are suitable for starting a rocket engine both in a low-pressure setting and in a high-pressure setting. According to the invention, said igniter includes a supply (21) of a first propellant (A), a supply (31) of a second propellant (B), a supply (41) of a high-pressure fluid (F), a first buffering vessel (22), a second buffering vessel (32), a first switching device (50), a second switching device (60), and a torch combustion chamber (10); an opening downstream from the first buffering vessel (22) and an opening downstream from the second buffering vessel (32) lead into the combustion chamber (10); the first switching device (50) and the second switching device (60) are configured to connect an opening upstream from the first buffering vessel (22) and an opening upstream from the second buffering vessel (32), respectively, to either the supply (21) of a first propellant (A) and to the supply (31) of a second propellant (B), respectively, or to the supply (41) of high-pressure fluid (F).