Integrated Rocket Accelerator Nozzle Design
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Solution Overview
Problem
Existing propulsion systems for vehicles, such as aircraft, face inefficiencies in providing high thrust during the boost phase while minimizing vehicle base drag, particularly at low Mach numbers, due to suboptimal airbreathing flowpaths and constraints on rocket size and placement that affect scramjet engine performance.
Innovation Solution
An airframe-integrated hydrocarbon-fueled airbreathing engine combined with a hydrocarbon propellant rocket positioned to utilize the aft-body contour as a high area ratio self-compensating nozzle, allowing for larger rockets and reduced base drag without compromising high-speed performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If external rockets are used to provide high thrust during boost phase, then acceleration capability is improved, but vehicle base drag increases due to large aft facing areas
Solution Approach 1:
The patent merges the rocket propulsion system with the vehicle airframe by integrating the rocket nozzle with the vehicle's aft-body contour. The rocket exhaust flows through a nozzle that utilizes the vehicle's own body shape, combining two separate systems (rocket and airframe) into a unified structure that eliminates the need for separate external rocket mounts and reduces base drag.
Solution Approach 2:
The aft-body contour of the vehicle serves multiple functions: it acts as both the vehicle's structural body and as the rocket nozzle expansion section. This multi-functional design allows the same structure to provide both aerodynamic shaping and rocket exhaust flow path, eliminating the need for additional external rocket structures that would increase base drag.
2Object-generated harmful factors
If RBCC systems use small rockets at the throat to entrain airflow, then base drag is reduced, but thrust levels are constrained due to throat blockage and form drag
Solution Approach 1:
The patent transitions from using small rockets positioned at the throat (one-dimensional constraint) to utilizing the entire aft-body contour as a large-area nozzle (three-dimensional solution). By expanding the rocket exhaust flow path into the available volume behind the vehicle, the system achieves high thrust without throat blockage constraints.
Solution Approach 2:
The invention changes the key parameter of nozzle area from a small throat area to a large effective area utilizing the entire aft-body contour. This parameter change allows the rocket system to operate at high thrust levels without the throat blockage and form drag penalties that constrain traditional RBCC systems.
3Speed
If rockets are positioned to provide high thrust, then acceleration is improved, but scramjet engine performance is compromised by excessive throat blockage and form drag
Solution Approach 1:
The patent segments the propulsion system into distinct functional zones: the scramjet intake and combustion section for high-speed operation, and the aft-body integrated nozzle section for rocket acceleration. This segmentation allows each subsystem to operate optimally without interfering with the other, preventing throat blockage issues while maintaining scramjet performance.
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
This configuration achieves high thrust levels with moderate efficiency and low vehicle base drag, eliminating the need for external burning and reducing scramjet engine constraints, enabling efficient operation across a range of altitudes and Mach numbers.
Implementation Method 1
at least one hydrocarbon propellant rocket positioned so as to use the aft-body contour of the vehicle directly for flow expansion
Implementation Method 2
high area ratio self-compensating nozzle
Implementation Method 3
at least one hydrocarbon propellant rocket positioned so as to use the aft-body contour of the vehicle directly for flow expansion
Data Source
AI summary
The present invention relates to a propulsion system for a vehicle. The propulsion system has an airframe integrated hydrocarbon fueled airbreathing engine, such as a ramjet or a scramjet. The propulsion system further has at least one rocket positioned so as to use the aft body contour of the vehicle directly for flow expansion. In a preferred embodiment, a plurality of rockets are arrayed across the width of the engine nozzle.