Inner Reactor Housing for Ammonium Dinitramide Thrusters
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Solution Overview
Problem
Existing ammonium dinitramide-based liquid monopropellant thrusters require high pre-heating power and time to reach operational temperature, leading to energy inefficiency and potential hard starts due to heat loss and ignition delays, especially in larger engines.
Innovation Solution
Incorporating an inner reactor housing that separates the heat bed and catalyst bed from the inner surface of the reactor, allowing for quicker pre-heating and reduced energy consumption by minimizing heat loss, and using a catalytic heat bed with internal structural elements to enhance heat transfer and reduce hard starts during pulsed mode firing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If pre-heating power is increased to reduce pre-heating time, then pre-heating speed is improved, but energy consumption increases
Solution Approach 1:
The reactor is divided into an inner reactor housing and an outer reactor housing, creating a segmented structure that allows for targeted thermal management. The inner housing contains the heat bed and catalyst bed, while the outer housing provides thermal insulation, enabling efficient heat retention in the critical zones without requiring excessive pre-heating power.
Solution Approach 2:
The patent converts the harmful heat loss to the surroundings into a beneficial thermal insulation system. The outer reactor housing acts as a thermal barrier that traps heat within the inner housing, turning what would be wasted energy into useful thermal energy that maintains operating temperature and reduces pre-heating requirements.
2Reliability
If pre-heating temperature is increased to prevent hard starts, then reliability is improved, but energy consumption increases
Solution Approach 1:
The reactor performs preliminary heating of the inner housing and critical components before full operation begins. The outer housing pre-heats the inner housing, and the heat bed pre-heats the catalyst bed, ensuring that all components reach appropriate temperatures before propellant injection, thereby preventing hard starts without requiring excessive continuous power.
Solution Approach 2:
The system uses its own operational heat to maintain pre-heating temperatures. During operation, the heat generated by the catalyst bed and combustion chamber continuously heats the monopropellant and maintains the heat bed temperature, creating a self-sustaining thermal system that reduces external power requirements.
3Force
If reactor size is increased for larger thrust, then thrust capability is improved, but heat loss increases
Solution Approach 1:
The reactor is segmented into an inner housing containing active components and an outer housing providing insulation. This segmentation allows larger reactors to maintain efficient heat retention by isolating the heat-generating zones from the larger external surface area, reducing proportional heat loss as size increases.
Solution Approach 2:
The outer reactor housing acts as an intermediary thermal barrier between the inner reactive zone and the external environment. This intermediary structure reduces direct heat loss from the combustion chamber and catalyst bed to the surroundings, allowing larger reactors to operate more efficiently.
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 reduces pre-heating time and energy consumption, minimizes hard starts, and improves the recovery time of the reactor, effectively addressing the inefficiencies and reliability issues in larger thrusters.
Implementation Method 1
an inner reactor housing (45), separating the heat bed and catalyst bed from contact with the inner surface of the hollow body (5), is included in the reactor
Implementation Method 2
a catalyst bed (30) of porous catalyst pellets (35)
Implementation Method 3
a heat bed (25) comprising heat bed material (26)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Reactor for the decomposition of ammonium dinitramide-based liquid monopropellants into hot combustible gases for combustion in a combustion chamber (50), and rocket engine or thruster comprising such reactor, which reactor comprises an inner reactor housing (45) accommodating a heat bed (25) and a catalyst bed (30), and separating the heat bed and catalyst bed from contact with the inner surface of the reactor housing (5).