Cryogenic Propellant Tank Segmentation for Pump Cavitation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cryogenic propellant tanks in spacecraft launch vehicles experience temperature differences between the gas and liquid phases, leading to propellant heating and cavitation issues in pumps, which are mitigated by increasing tank pressure, resulting in propellant loss and structural mass increases.
Innovation Solution
A cryogenic propellant tank design with a primary and secondary volume connected by a valve, where the primary volume is pressurized for attitude control and the secondary volume is pressurized to prevent cavitation in the pump, allowing efficient use of all propellant while minimizing structural impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tank pressure is significantly increased to prevent cavitation in pumps, then pump reliability is improved, but tank structural mass increases and propellant loss occurs
Solution Approach 1:
The tank is divided into two separate volumes: a first volume for storing cryogenic propellant and a second volume for storing pressurized gas. This segmentation allows each volume to be optimized independently - the first volume can be designed for cryogenic storage requirements while the second volume is designed to withstand high pressures without requiring the entire tank structure to be reinforced, thereby reducing overall structural mass.
Solution Approach 2:
A valve acts as an intermediary component connecting the first and second volumes. The valve controls the transfer of propellant between volumes and can isolate the high-pressure second volume from the cryogenic first volume, preventing unwanted interaction while allowing the system to benefit from both high pressure (for pump protection) and cryogenic storage conditions.
2Reliability
If tank pressure is significantly increased to prevent cavitation in pumps, then pump reliability is improved, but propellant loss increases
Solution Approach 1:
By segmenting the tank into two volumes, the invention allows the cryogenic propellant in the first volume to remain at low pressure and temperature without being forced into the high-pressure second volume. This prevents unnecessary propellant transfer and loss while still providing high pressure to the pump through the controlled valve mechanism.
Solution Approach 2:
Instead of pressurizing the entire tank volume, the invention applies high pressure only to the second volume (gas storage space), which is sufficient to prevent cavitation in the pump. The first volume (propellant storage) maintains normal cryogenic pressure, avoiding excessive propellant loss.
3Reliability
If the gas phase temperature is increased to ensure pump compatibility, then pump reliability is improved, but propellant temperature increase at gas/liquid interface worsens cavitation risk
Solution Approach 1:
The tank is segmented into a first volume for cryogenic propellant storage and a second volume for warmer gas storage. This spatial separation allows the gas phase to be stored at higher temperatures (90K for oxygen, 21K for hydrogen) without directly heating the liquid propellant, as the two phases are isolated by the valve and physical separation.
Solution Approach 2:
The valve serves as an intermediary that can isolate the warm gas phase in the second volume from the cold propellant in the first volume. This prevents thermal coupling between the gas and liquid phases, maintaining the propellant at its optimal cryogenic temperature while still allowing the gas to be at a temperature suitable for pump compatibility.
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 tank design enables the use of all propellant without unnecessary mass increase, as the secondary volume is structured to withstand higher pressures, preventing cavitation and optimizing propellant delivery to the engine.
Implementation Method 1
a valve configured to selectively allow the passing of fluid from the primary volume towards the secondary volume, or to isolate the secondary volume from the primary volume
Implementation Method 2
the primary volume having a primary orifice adapted to be connected to a first pressurization source
Implementation Method 3
the secondary orifice adapted to be connected to a second pressurization source... the second pressurization source is configured so as to selectively pressurize the secondary volume for conveying of the propellant contained in the secondary volume towards the engine
Implementation Method 4
a pump connected to the secondary orifice, the pump being configured to convey the propellant contained in the secondary volume towards the engine through the supply line
Data Source
AI summary
Cryogenic propellant tank (1) for a spacecraft engine, comprising an external enclosure (10) defining an internal volume, characterized in that the internal volume of the tank comprises a primary volume (V1) and a secondary volume (V2) connected to the primary volume (V1) via a valve (20) configured to selectively allow a passage of fluid from the primary volume (V1) to the secondary volume (V2), or to isolate the secondary volume (V2) from the primary volume (V1), the primary volume (V1) having a primary orifice (11) adapted to be connected to a first pressurization source (41), the secondary volume (V2) having a supply orifice (4) adapted to be connected to a supply line of a spacecraft engine (30), and a secondary orifice (12) adapted to be connected to a second pressurization source (42).