Constant Volume Rocket Motor Using Reciprocating Thrust Valve
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional constant-pressure bipropellant thrusters suffer from inefficient combustion and potential for catastrophic failure during pulse-mode operation due to transient phenomena, propellant accumulation, and thermal instability, which degrades performance and safety in high-precision spacecraft applications.
Innovation Solution
A constant-volume rocket motor utilizing a Reciprocating Thrust Valve (RTV) with a canted-coil reciprocating seal, allowing controlled injection, mixing, ignition, and combustion in a sealed chamber, eliminating detonations and minimizing propellant loss and contamination, and enabling precise timing and scalability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If constant-pressure combustion is used in conventional thrusters, then the system structure is simpler, but combustion efficiency degrades and propellant loss increases during pulse-mode operation
Solution Approach 1:
The patent changes the fundamental combustion parameter from constant-pressure to constant-volume operation. By maintaining a sealed combustion chamber that prevents propellant escape during the combustion phase, the system achieves complete combustion and eliminates dribble loss while managing thermal loads through controlled expansion and cooling phases.
2Loss of substance
If propellant flow control valves are closely coupled to the injector to minimize dribble volume, then propellant loss is reduced, but thermal soak-back causes overheating of valves during pulse-mode operation
Solution Approach 1:
The patent segments the valve system into two distinct components: flow control valves that are decoupled from the combustion chamber and positioned remotely, and a separate reciprocating thrust valve that controls the sealed chamber. This segmentation allows the flow control valves to operate in a cool environment while the thrust valve manages the thermal environment of the combustion chamber, eliminating thermal soak-back effects.
3Measurement precision
If pulse-mode operation with short impulse bits is implemented for precision control, then spacecraft maneuver precision is improved, but transient phenomena cause performance degradation and potential catastrophic failure
Solution Approach 1:
The patent implements preliminary actions by pre-charging the combustion chamber with propellants before ignition, and by using a reciprocating thrust valve that is positioned and sealed in advance. This ensures that when the ignition occurs, all propellants are already in place for complete combustion, eliminating transient losses and preventing catastrophic failure during short pulse operations.
4Productivity
If constant-volume combustion is used with a sealed chamber, then combustion efficiency and thrust precision are improved, but the device complexity increases due to the reciprocating thrust valve mechanism
Solution Approach 1:
The reciprocating thrust valve is designed to be actuated by the combustion pressure itself rather than requiring an external actuation system. The high-pressure combustion gases automatically push the valve open, and the valve closes when pressure equalizes or reverses, making the valve self-actuating and eliminating the need for complex external actuators while maintaining the sealed chamber benefits.
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 RTV design achieves higher efficiency, reduced weight, and improved reliability by minimizing propellant dribble and thermal soak-back, enabling precise control and scalability from millinewton to kilonewton thrust ranges with reduced risk of contamination and failure.
Implementation Method 1
Fuel enters the combustion chamber at low pressure with the RTV closed. The valve opens after or during combustion when combustion chamber pressure is at or near maximum.
Implementation Method 2
Opening and closing of the combustion chamber exhaust outlet is controlled by an actuated reciprocating thrust valve (RTV)
Implementation Method 3
A constant-volume rocket motor utilizing a Reciprocating Thrust Valve (RTV) with a canted-coil reciprocating seal, allowing controlled injection, mixing, ignition, and combustion in a sealed chamber
Implementation Method 4
Fuel enters the combustion chamber at low pressure with the RTV closed. The valve opens after or during combustion when combustion chamber pressure is at or near maximum.
Data Source
AI summary
The present invention is a constant volume rocket motor that uses a non-detonating constant-volume, bipropellant combustion process in pulse-mode operation. Opening and closing of the combustion chamber exhaust outlet is controlled by an actuated reciprocating thrust valve (RTV). Fuel enters the combustion chamber at low pressure with the RTV closed. The valve opens after or during combustion when combustion chamber pressure is at or near maximum. The motor has applications in reaction control systems and attitude control systems in spacecraft.