Joule-Thomson Stirling Cooler Integration for Fast Cryogenic Readiness
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Solution Overview
Problem
Current cryogenic coolers, such as Joule-Thomson and Stirling coolers, face limitations in flight vehicle applications due to logistical constraints, contamination risks, and trade-offs between quick ready times and long operating times, compromising vehicle performance.
Innovation Solution
A cooling system integrating a Joule-Thomson valve and counter-flow heat exchanger with a Stirling cooler's cold finger, utilizing an adapter to transfer heat from the thermal load to both the cold finger and refrigerant, allowing for quick cooling and extended operation by minimizing size and thermal mass, and leveraging inefficiencies to enhance Stirling cooler performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a Joule-Thomson cooler is used to achieve quick cooling ready time, then the cooling speed is improved, but the operating time is limited due to pressurized gas constraints
Solution Approach 1:
The patent combines a Joule-Thomson cooler and a Stirling cooler into a single integrated system. The Joule-Thomson portion provides rapid initial cooling using pressurized gas, while the Stirling portion takes over for sustained operation using electrical power, thus resolving the contradiction between quick ready time and long operating time.
Solution Approach 2:
The Joule-Thomson cooler performs preliminary cooling action to rapidly bring the thermal load close to the target temperature, after which the Stirling cooler maintains the temperature. This preliminary action by the Joule-Thomson section enables the system to achieve quick ready time while the Stirling section ensures long operating duration.
2Duration of action of moving object
If a Stirling cooler is used to achieve long operating time, then the duration of operation is improved, but the cooling speed is reduced
Solution Approach 1:
The integrated system merges the strengths of both cooler types: the Stirling cooler provides long-duration operation using electrical power, while the Joule-Thomson cooler supplements it with rapid cooling capability, thus resolving the contradiction between operating time and cooling speed.
Solution Approach 2:
The system operates in periodic phases: initially the Joule-Thomson cooler provides rapid cooling, then the Stirling cooler maintains temperature for extended periods. This periodic switching between cooling modes allows the system to achieve both quick ready time and long operating time.
3Power
If pressurized gas is used to power the Joule-Thomson cooler, then the cooling performance is improved, but the device complexity and maintenance requirements increase
Solution Approach 1:
The Stirling cooler acts as an intermediary that converts electrical power into mechanical cooling, replacing the need for pressurized gas storage and handling systems. This substitution reduces device complexity and maintenance requirements while maintaining adequate cooling performance for the application.
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 system achieves rapid cooling of infrared detectors to cryogenic temperatures, extending operating times while minimizing size and weight, thus enhancing the utility of flight vehicle systems by balancing quick ready times and long-term operation.
Implementation Method 1
Joule-Thomson cooler is a device that produces liquid refrigerant by use of a valve (known in the art as a 'Joule-Thomson valve') and counter flow heat exchanger. High-pressure gas is allowed to expand through the valve via an irreversible throttling process in which enthalpy is conserved, resulting in lowering of its temperature.
Implementation Method 2
The counter-flow heat exchanger transfers heat from the high-pressure incoming gas to the cooled exiting gas to decrease the enthalpy of the incoming gas and enable liquid production.
Implementation Method 3
A Stirling cycle cooler is an efficient and compact closed-cycle, electrically-driven cryogenic cooling device using a repeating reversible expansion of a gas.
Implementation Method 4
The regenerative heat exchanger (regenerator) is included in the expansion piston to thermally isolate gas at the compressor headspace from gas at the expansion headspace.
Data Source
AI summary
An apparatus includes a chamber, a first heat exchanger, an adapter, and a second heat exchanger. The first heat exchanger includes a cold finger positioned within the chamber. The second heat exchanger is positioned around an adapter and within the chamber. The second heat exchanger is a counter flow heat exchanger to precool refrigerant entering a Joule-Thomson valve. The adapter is positioned between the cold finger and the second heat exchanger. The adapter transfers heat from a thermal load to both the cold finger and the refrigerant emitted from the Joule-Thomson valve.