Integrated Ejector Isolation Valve for Propellant Tank Pressure Control
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Solution Overview
Problem
Ejectors used in propellant tanks face challenges in microgravity environments, such as ullage pressure collapse and inefficient propellant transfer due to the need for venting, which can lead to structural failures and inefficiencies in space transportation.
Innovation Solution
The system employs a pneumatically actuated poppet valve to control the secondary fluid inlet, allowing for simultaneous operation of the ejector and inlet valve, using a high-pressure motive fluid to manage ullage temperature and pressure without venting the tank, utilizing aerodynamic pumps or atomizers to mix and atomize the propellant, reducing pressure and temperature within the tank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate isolation valve is used upstream of the ejector, then the ejector can be isolated from the process when not operating, but the device complexity increases due to additional hardware and actuators
Solution Approach 1:
The patent combines the isolation valve and ejector into a single integrated unit where the valve is built into the ejector body. The valve assembly includes a valve body, valve seat, and actuator that are integrated with the ejector components, eliminating the need for a separate isolation valve and reducing overall system complexity while maintaining effective isolation capability.
Solution Approach 2:
The integrated ejector- valve unit serves multiple functions: it acts as both the ejector device for fluid mixing and momentum transfer, and as an isolation valve for sealing off the process when the ejector is not in use. The actuator controls both the valve operation and can trigger ejector operation, consolidating control functions.
2Reliability
If the ejector operates continuously to maintain vacuum, then vacuum conditions are preserved, but the ejector negatively affects the process when not needed
Solution Approach 1:
The system transitions from static continuous operation to dynamic on-demand operation. The integrated valve allows the ejector to be quickly isolated when not needed, enabling the system to adapt its operation state based on process requirements. The actuator can rapidly close the valve to isolate the ejector, preventing unnecessary interference with the process while maintaining vacuum when required.
3Stress or pressure
If venting is used to control tank pressure during propellant transfer, then pressure is relieved, but valuable liquid propellant is lost
Solution Approach 1:
The ejector acts as an intermediary device that manages pressure control without direct venting. By using the ejector to create vacuum and control ullage pressure through fluid dynamics rather than atmospheric venting, the system relieves pressure while containing all propellant within the closed system, eliminating the loss associated with traditional venting methods.
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 solution effectively prevents ullage pressure collapse, enables efficient propellant transfer in microgravity, and allows for propellant tank filling without venting, enhancing the reliability and efficiency of space transportation systems.
Implementation Method 1
A high-pressure motive fluid is accelerated through a nozzle to create a high-velocity fluid stream or jet that reduces local static pressure and thereby creates a vacuum
Implementation Method 2
The vacuum draws the liquid propellant into a mixing chamber where it is mixed with the high-velocity fluid stream through momentum transfer between the coflowing fluids
Implementation Method 3
The atomized spray is ejected into the ullage space of the propellant tank where evaporation of the atomized spray lowers the ullage gas temperature
Data Source
AI summary
Apparatus, systems and methods for pumping fluids, including for the purpose of controlling temperature and pressure in a propellant tank include a type of novel ejector, consisting of a typical ejector and an isolation valve integrated on the inlet of secondary fluid to an ejector, or suction chamber. The inlet valve is actuated by the application of the primary motive fluid pressure to a motive nozzle. The ejector is configured to operate when submerged in the secondary fluid.