Cryogenic Fluid Compression with Flow Retarder for Cavitation Control
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Solution Overview
Problem
Existing fluid compression systems face issues with cavitation due to pressure loss and thermal input, leading to inefficiencies in liquid hydrogen pumps, particularly during the transition between compression stages with different chamber volumes and piston strokes.
Innovation Solution
Incorporating an evacuation valve with a flow retarder to control the evacuation of excess liquid from the first compression chamber, using a porous material to attenuate the flow speed and pressure drop, thereby preventing vaporization and maintaining thermodynamic quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a light or channel connects the first compression chamber and the bath to naturally evacuate excess fluid, then the excess liquid can exit during compression, but this generates vaporization gas in the bath
Solution Approach 1:
The patent introduces an intermediary evacuation valve controlled by a valve mechanism that mediates between the first compression chamber and the bath. This valve can be opened to allow controlled evacuation of excess liquid while preventing uncontrolled flow that would generate vaporization gas. The valve acts as a mediator to control the evacuation process and minimize harmful effects.
Solution Approach 2:
The patent changes the parameter of flow control by using a valve mechanism that can adjust the evacuation rate. By controlling when the valve opens and closes, the system can evacuate excess liquid at optimal rates without creating conditions for vaporization. The valve control parameter allows precise regulation of liquid removal to prevent harmful vaporization effects.
2Productivity
If the chamber diameters are different but the piston stroke is the same, then the swept volumes can be different, but this creates complexity in managing fluid transfer between stages
Solution Approach 1:
The patent applies preliminary action by evacuating excess liquid from the first compression chamber before the fluid is transferred to the second compression chamber. This preliminary evacuation ensures that only the appropriate amount of liquid is transferred, simplifying the fluid transfer management despite different chamber volumes. The valve-controlled evacuation happens in advance to prepare the system for efficient transfer.
3Quantity of substance
If the evacuation orifice communicates directly with the enclosure, then excess liquid can exit quickly, but this causes pressure loss and thermal input leading to cavitation
Solution Approach 1:
The patent introduces an intermediary valve mechanism between the evacuation orifice and the enclosure. This valve mediates the liquid flow, controlling it to exit at a regulated rate rather than uncontrolled. The valve prevents sudden pressure changes and thermal input that would cause cavitation, while still allowing adequate liquid removal. It acts as a buffer between the evacuation system and the enclosure.
4Productivity
If the intake system uses valves to prevent fluid exit during compression, then filling efficiency improves, but this requires precise valve timing and control
Solution Approach 1:
The patent applies self-service by designing the valve mechanism to automatically respond to pressure differential changes during the compression cycle. The valve opens and closes based on the natural pressure differences created during intake and compression phases, eliminating the need for complex external control systems. The valve serves itself by using the process conditions to regulate its own operation, simplifying the overall control system while maintaining high filling efficiency.
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
Enhances the performance and volumetric efficiency of liquid hydrogen pumps by minimizing pressure loss and thermal input, reducing cavitation, and ensuring efficient transfer between compression stages.
Implementation Method 1
a nozzle made of porous material whose permeability is preferably greater than five darcy
Implementation Method 2
configured to attenuate the speed and/or the intensity of the flow of evacuated liquid by limiting its pressure drop
Implementation Method 3
a first compression chamber, a second compression chamber... configured to allow the entry of fluid into said first compression chamber... configured to allow the transfer of pre-compressed fluid
Implementation Method 4
an evacuation orifice communicating with the second compression chamber and configured to allow the exit of compressed fluid into the second compression chamber
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a fluid compression apparatus (1) comprising a sealed enclosure (13) intended to contain a bath (16) of cryogenic fluid, a first (3) and a second compression chamber (4), a system (2) for admission into the first chamber (3), a system (6) for transfer from the first (3) to the second (4) chamber, the apparatus (1) further comprising a communicating discharge orifice (7) for the outlet of compressed fluid from the second chamber, the apparatus (1) further comprising a discharge orifice provided with a valve (9) for discharging from the first compression chamber (3) to the bath (16) to allow excess liquid to escape during compression of fluid in the first chamber (3), the discharge orifice communicating with the enclosure (13) via at least one flow retarder (10) configured to attenuate the speed and/or intensity of the flow of liquid discharged by limiting its pressure drop.