Vortex Oxidizer Injection for Linear Throttling in Hybrid Rocket Engines
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Solution Overview
Problem
Traditional hybrid rocket engines face challenges with throttling due to Nitrous Oxide dissociation, pressure drops, and inefficient combustion stability, particularly in axial oxidizer injection systems, which result in low regression rates and unstable ignition, and the use of hypergolic fluids complicates safety and efficiency.
Innovation Solution
A hybrid rocket engine design featuring a vortex injector with a pre-swirl chamber transforming axial flow into centrifugal flow, a linear throttle valve for precise control, and a cylindrical injection chamber with tangential orifices, creating a self-sustaining vortex flow field that enhances regression rates and combustion stability by maintaining a linear flow rate and reducing pressure drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional axial oxidizer injection systems are used, then the engine structure is simple, but the regression rate is low and combustion stability is poor
Solution Approach 1:
The patent introduces a vortex flow field that transforms the traditional axial flow into a rotational vortex flow pattern. The oxidizer is injected tangentially to create a swirling flow that enhances mixing with fuel and improves heat transfer to the grain surface, thereby increasing regression rate while maintaining combustion stability
Solution Approach 2:
The injection system transitions from one-dimensional axial flow to three-dimensional vortex flow by injecting oxidizer tangentially at multiple angles. This dimensional change creates a more complex flow pattern that enhances combustion efficiency and regression rate without significantly increasing structural complexity
2Ease of operation
If traditional ball valves are used for throttling, then the valve structure is simple, but the flow rate control is exponential and not linear
Solution Approach 1:
The patent employs a linear throttle valve with a needle-style actuator that provides linear flow rate control. By changing the valve geometry from a ball valve configuration to a needle valve configuration, the flow rate becomes linearly proportional to the valve actuation position, enabling precise throttle control for orbital maneuvers
3Reliability
If globe valves are used for throttling, then flow control is achievable, but pressure drops and flow turbulence occur
Solution Approach 1:
The patent extracts the throttling function from traditional valve designs and integrates it directly into the oxidizer injection system. The linear throttle valve is positioned upstream of the vortex injector, allowing flow control without creating additional pressure drops or turbulence that would occur with separate globe valve installations
4Ease of operation
If pintle valves are used for throttling, then linear flow control is possible, but pressure drops occur during valve actuation
Solution Approach 1:
The linear throttle valve design prepares the oxidizer flow in advance by maintaining steady pressure through a streamlined needle actuator. The valve geometry is designed to minimize flow separation and turbulence during actuation, preventing pressure drops that would occur with traditional pintle valve designs
5Productivity
If axial oxidizer injection is used, then the injection system is simple, but boundary layers build up and heat transfer is reduced
Solution Approach 1:
The vortex injector creates a rotational flow pattern that prevents boundary layer buildup on the injection chamber walls. The tangential injection angles generate centrifugal forces that keep the oxidizer-fuel mixture away from the walls, maintaining thin boundary layers and enhancing heat transfer to the grain surface
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 design achieves a high regression rate and efficient combustion stability by maintaining a linear flow rate, reducing pressure drops, and eliminating hotspots, thereby increasing thrust and volumetric efficiency while allowing for fine throttle control and safe operation.
Implementation Method 1
a pre-swirl chamber that transforms axial flow of the injection fluid into a centrifugal flow and distributes the centrifugal flow of the injection fluid to the one or more injection orifices
Implementation Method 2
creating a self-sustaining vortex flow field that enhances regression rates and combustion stability by maintaining a linear flow rate and reducing pressure drops
Data Source
AI summary
A hybrid rocket engine with a vortex flow field injection system that produces a high-speed sustained vortex flow field is described. The hybrid rocket engine includes a generally cylindrical injection chamber with an inner circumference to comprise an outer edge of a solid propellant grain in the hybrid rocket engine. The engine also includes an injection system that has a throttle valve and an injector that injects injection fluid into the engine and produces a vortex flow-field for the injected fluid. The injector includes at least one primary feed line that distributes the injection fluid throughout a pre-swirl chamber and multiple orifices along an inner edge of the injection chamber. The pre-swirl chamber connects to the injection chamber and at least one of the primary feed lines and redirects a primary fluid flow of the injected fluid from a primary axial direction to a centrifugal direction.