Saturated Liquid Pump Arrangement With Expansion Subcooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing pump arrangements for saturated liquids face challenges in maintaining net positive suction pressure (NPSP) while minimizing complexity, weight, and avoiding cavitation, particularly in space applications.
Innovation Solution
A pump arrangement that includes a tank, heat exchanger, expansion valve, and compressor or jet pump to subcool the liquid, increase NPSP, and manage vapor pressure efficiently, without requiring additional gas sources or complex heaters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If pressure in the tank is increased using vapor or other gases, then net positive suction pressure is improved, but device complexity increases
Solution Approach 1:
The system uses the liquid being pumped itself to generate the pressurizing vapor through controlled evaporation in the tank, eliminating the need for external gas sources or complex pressurization systems. The expansion valve creates a pressure differential that drives this self-service mechanism.
Solution Approach 2:
The invention utilizes phase transition of the liquid to vapor through controlled evaporation in the tank. The expansion valve creates conditions where liquid evaporates to form vapor that increases tank pressure, directly improving net positive suction pressure without external systems.
2Stress or pressure
If heating vapor in the tank is used, then net positive suction pressure is improved, but energy consumption increases
Solution Approach 1:
The system uses isenthalpic expansion through the expansion valve to create a pressure differential that drives liquid evaporation. This phase transition from liquid to vapor occurs without external heating, using the inherent energy of the fluid system itself.
Solution Approach 2:
The invention replaces thermal heating systems with a mechanical expansion valve that creates pressure differentials. This substitution eliminates the need for external heaters or energy input, using fluid dynamics instead of thermal energy.
3Stress or pressure
If a pre-pump is used, then net positive suction pressure is improved, but device complexity and weight increase
Solution Approach 1:
The system uses the main pump's own suction side to create the pressure differential needed for evaporation. The expansion valve connects the suction side to the tank, allowing the pump's operation itself to drive the pressurization mechanism without requiring a separate pre-pump.
Solution Approach 2:
The expansion valve serves multiple functions: it creates the pressure differential for evaporation, controls vapor generation, and utilizes the pump's suction side pressure. This multi-functionality eliminates the need for dedicated pre-pump components.
4Stress or pressure
If subcooling the liquid at pump inlet by low pressure evaporation is used, then net positive suction pressure is improved, but additional weight and complexity increase
Solution Approach 1:
The system uses the liquid being pumped to provide the cooling effect through its own evaporation. The evaporating liquid absorbs heat from the bulk liquid, subcooling it without requiring external refrigeration systems or additional cooling components.
Solution Approach 2:
The invention uses phase transition of a fraction of the liquid from liquid to vapor. This evaporation process absorbs latent heat, subcooling the remaining liquid and improving its density and net positive suction pressure without external cooling systems.
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 effectively increases NPSP, reduces cavitation risk, and simplifies operation by using passive components, making it suitable for various atmospheric conditions and space applications.
Implementation Method 1
the expansion valve inlet is arranged downstream the liquid outlet of the heat exchanger or the tank for receiving and expanding a fraction of liquid flowing through the pump arrangement and routing it into the coolant input to at least partially evaporate and receive evaporation enthalpy of the liquid to be subcooled
Implementation Method 2
the heat exchanger is designed to sub-cool the saturated liquid
Data Source
AI summary
A pump arrangement for providing a saturated or subcooled liquid includes a tank for saturated liquid, a heat exchanger for cooling the saturated liquid, a pump, an expansion valve, and an output for feeding saturated or subcooled liquid to a consumer. A tank outlet is in fluid communication with a liquid inlet of the heat exchanger, such that saturated liquid stored inside the tank can flow into the heat exchanger designed to sub-cool the saturated liquid. A liquid outlet of the heat exchanger is in fluid communication with a pump inlet. The expansion valve outlet is in fluid communication with a coolant inlet of the heat exchanger. An expansion valve inlet is arranged for receiving and expanding a fraction of liquid flowing through the pump arrangement and routing it into the coolant input to at least partially evaporate and receive evaporation enthalpy of the liquid to be subcooled.