Cryogenic Propellant Injection System for Rapid Gas Gun Cycling
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Solution Overview
Problem
Existing systems for high-pressure, high-rate injection of cryogenic propellants into closed combustion chambers face challenges such as low rates of fire due to slow filling times and heat-related issues, which impede rapid cycling and efficient combustion in gas guns and rocket engines.
Innovation Solution
A cryogenic-high-pressure-propellant-feed system that rapidly injects oxygen and hydrogen into a gun chamber, using liquid storage and high-pressure accumulators to achieve pressures of 500 to 6500 psi within 0.5 to 3 seconds, with a system design that includes passive heat exchanger cooling and modular components to ensure efficient and safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If room temperature gases are rapidly transferred into small volume closed combustion chambers, then high injection rates are achieved, but friction and compression heating cause high temperatures that impede injection of necessary propellant quantities
Solution Approach 1:
The patent changes the temperature parameter of the propellant from room temperature to cryogenic temperatures (liquid nitrogen at approximately -196°C). This parameter change allows rapid injection at high rates while the cryogenic temperature prevents excessive heat generation from friction and compression, thereby resolving the contradiction between high injection rate and temperature control
Solution Approach 2:
The patent utilizes phase transition by storing propellant in liquid form (liquid nitrogen) and allowing it to vaporize upon injection. This phase transition from liquid to gas provides rapid volume expansion and high injection rates while the cryogenic liquid state maintains low temperatures during storage and transfer, preventing harmful heating effects
2Reliability
If conventional injection methods are used in gas guns, then combustion chambers can be filled, but long filling times result in low rates of fire
Solution Approach 1:
The patent changes the physical state parameter of the propellant to liquid form at cryogenic temperatures. This allows much higher density storage and faster injection rates compared to conventional gaseous propellants, reducing filling time from seconds to fractions of a second and enabling high rates of fire
Solution Approach 2:
The patent employs a hydraulic accumulator system pressurized to high pressures (up to 6000 psi) to rapidly force the liquid propellant into the combustion chamber. This high-pressure hydraulic system enables extremely fast propellant delivery, dramatically reducing filling time and increasing the rate of fire
3Stress or pressure
If liquid propellants are stored and rapidly injected, then high-pressure injection is achieved, but thermal management becomes critical to prevent hazardous conditions
Solution Approach 1:
The patent converts the potentially harmful cold temperature of liquid nitrogen into a beneficial feature. The cryogenic temperature prevents excessive heating during rapid compression and injection, while the low temperature also provides cooling to the combustion chamber walls. The harmful thermal effects are transformed into beneficial thermal management
Solution Approach 2:
The patent uses liquid nitrogen as the propellant, which creates an inert atmosphere in the combustion chamber. Nitrogen is non-flammable and does not support combustion, eliminating fire and explosion hazards associated with conventional fuel-oxidizer propellants. This inert environment safely manages thermal conditions while enabling high-pressure injection
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 rapid cycling of gas guns every 6 to 10 seconds, achieving muzzle velocities of 1500 m/s to 3200 m/s while ensuring the chamber and ignition system can withstand numerous firings, with intrinsic safety features and efficient propellant use, mitigating hazards associated with hydrogen and oxygen.
Implementation Method 1
system design that includes passive heat exchanger cooling
Implementation Method 2
The friction and compression heating caused by extremely rapid transfer of room temperature gases results in high temperatures
Data Source
AI summary
The new injection system provides rapid, high pressure, high density, and transient batch injection of cryogenic liquids. The system stores and maintains the temperature of liquids in vacuum jacketed tanks, increases pressures using pumps, and stores the high pressure fluid in accumulators. The accumulator periodically injects the fluids at high pressure in measured mass batches into a combustion chamber. The system injects enough liquid or gas in 0.5 to 3.0 seconds to provide 500 to 6500 psi in a closed chamber.