Reversible-Flow Discharge Orifice for Rocket Engine Fuel Evacuation
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Solution Overview
Problem
Existing rocket engine discharge orifices experience high pressure differential during shutdown, causing inefficiencies in reversing fuel flow due to their sharp, square-cornered design, which leads to increased resistance and pressure drops, hindering effective evacuation of fuel from the system.
Innovation Solution
A reversible-flow discharge orifice with a throat and entrance and exit ramps designed to minimize pressure drop during reverse flow, featuring a convergent entrance and a divergent exit ramp with a rounded corner, allowing for smooth flow reversal while maintaining stable flow separation during steady-state operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a discharge orifice with a sharp, square-cornered design is used, then stable flow separation is achieved during steady-state operation, but high pressure differential and increased resistance occur during shutdown when flow is reversed
Solution Approach 1:
The orifice is designed with asymmetric geometry where the entrance has a well-rounded shape and the exit has a squared-off trailing edge with a ninety-degree sharp corner. This asymmetric configuration creates different flow characteristics for forward and reverse flow directions, optimizing steady-state operation while managing shutdown behavior.
Solution Approach 2:
The entrance of the orifice features a well-rounded curved geometry rather than a sharp corner. This curvature promotes smooth flow attachment during steady-state operation and reduces flow separation, while the contrasting sharp exit edge creates the desired flow characteristics for both operating conditions.
2Reliability
If a discharge orifice with a well-rounded entrance and constant-diameter throat is used, then repeatable flow characteristics are achieved, but resistance increases during reverse flow evacuation
Solution Approach 1:
The orifice employs asymmetric geometry with a well-rounded entrance and a squared-off exit with a ninety-degree sharp corner. This asymmetry creates different flow behaviors for forward and reverse directions, achieving repeatable characteristics during steady-state operation while managing resistance during shutdown evacuation.
Solution Approach 2:
Different sections of the orifice have different geometric properties: the entrance has a well-rounded shape for smooth flow attachment, the throat has a constant diameter for stable flow, and the exit has a sharp corner for controlled flow separation. Each local geometry is optimized for its specific function in the overall flow management.
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 pressure drop during shutdown, enabling efficient evacuation of fuel from the rocket engine system by minimizing resistance during reverse flow without compromising flow separation during steady-state operation, thus optimizing system performance.
Implementation Method 1
a squared-off trailing edge having a ninety-degree, sharp corner, which provide a repeatable, non-recoverable pressure drop for the flow of liquid hydrogen
Implementation Method 2
designed to minimize pressure drop during reverse flow
Data Source
Figure 1~2
Figure 3~4
AI summary
A rocket engine fluid-flow system (10) includes a pump (16) fluidly interconnecting a fluid source (12) to a combustion chamber (36). A nozzle (15) is in fluid communication with the combustion chamber (36) and includes coolant tubes (26) fluidly arranged between the pump (16) and the combustion chamber (36). An orifice (24) has a throat (50) and is fluidly arranged between the pump (16) and the coolant tubes (26). The orifice (24) has entrance and exit ramps (52, 54) arranged on either side of the throat (50). The exit ramp (54) has an exit ramp surface (58) with a divergent angle (56) that is less than a right angle. The entrance ramp (52) provides a smooth approach to the orifice throat (50). In one example, the exit ramp (54) includes an exit ramp surface (58) having a divergent angle (56) of 20-60°. An exit ramp radius (60) is less than twice the throat radius (62) in one example.