초록 ▼

A densifier (10) for simultaneously densifying two cryogenic liquids at different temperatures is provided. The densifier (10) has a thermoacoustic heat engine (20), a resonance tube (18) and a two stage pulse tube refrigerator (40). The thermoacoustic heat engine (20) generates oscillatory acoustic

A densifier (10) for simultaneously densifying two cryogenic liquids at different temperatures is provided. The densifier (10) has a thermoacoustic heat engine (20), a resonance tube (18) and a two stage pulse tube refrigerator (40). The thermoacoustic heat engine (20) generates oscillatory acoustical power required to generate net refrigeration power in the two-stage pulse tube refrigerator (40). The first stage (100) densifies a first cryogenic liquid to a first cryogenic temperature, and the second stage (200) densifies a second cryogenic liquid to a second, lower cryogenic temperature. The thermoacoustic heat engine (20) converts thermal energy to the oscillatory acoustical power required to generate net refrigeration in the first (100) and second ( 200) stages of the pulse tube refrigerator (40). No mechanical energy input is required, and therefore the invented densifier (10) has no moving parts.

대표청구항 ▼

What is claimed is: 1. A densifier for densifying two cryogenic liquids, said densifier comprising an oscillatory power source for generating oscillatory power, a resonance tube, and a pulse tube refrigerator, said pulse tube refrigerator being a two-stage pulse tube refrigerator having a first sta

What is claimed is: 1. A densifier for densifying two cryogenic liquids, said densifier comprising an oscillatory power source for generating oscillatory power, a resonance tube, and a pulse tube refrigerator, said pulse tube refrigerator being a two-stage pulse tube refrigerator having a first stage refrigeration unit and a second stage refrigeration unit, said first stage refrigeration unit being adapted to supercool a first cryogenic liquid to a first cryogenic temperature, said second stage refrigeration unit being adapted to supercool a second cryogenic liquid to a second cryogenic temperature, wherein said second cryogenic temperature is lower than said first cryogenic temperature. 2. A densifier according to claim 1, said oscillatory power having a frequency of at least 2 Hz. 3. A densifier according to claim 1, said resonance tube being about 45 feet in length. 4. A densifier according to claim 3, said resonance tube having a diameter of 4-5 inches. 5. A densifier according to claim 1, said densifier being a fully acoustic densifier wherein said oscillatory power source is an acoustic heat engine and said oscillatory power is oscillatory acoustical power. 6. A densifier according to claim 5, said acoustic heat engine being a thermoacoustic prime mover. 7. A densifier according to claim 1, said densifier further comprising a working fluid. 8. A densifier according to claim 7, said working fluid being helium having an initial pressure of 200-1000 psia. 9. A densifier according to claim 1, wherein at least one of said first stage refrigeration unit and said second stage refrigeration unit is an orifice pulse tube refrigeration unit. 10. A densifier according to claim 9, wherein said orifice pulse tube refrigeration unit has a primary orifice and a secondary orifice. 11. A densifier according to claim 9, wherein said orifice pulse tube refrigeration unit has an inertance tube and a reservoir volume. 12. A densifier according to claim 1, said first stage refrigeration unit comprising a first stage cold heat exchanger, said second stage refrigeration unit comprising a second stage cold heat exchanger, wherein said first cryogenic liquid is densified in said first stage cold heat exchanger and said second cryogenic liquid is densified in said second stage cold heat exchanger. 13. A densifier according to claim 12, said first stage refrigeration unit further comprising a first stage regenerator and a first stage pulse tube, said second stage refrigeration unit further comprising a second stage regenerator, wherein said first stage cold heat exchanger is a common thermal block. 14. A densifier according to claim 13, wherein said common thermal block is a shell-and-tube heat exchanger having a shell-side to accommodate a working fluid and a tube-side to accommodate said first cryogenic liquid, said shell-side having an inlet, a first outlet and a second outlet, said inlet of said shell-side being connected to said first stage regenerator, said first outlet of said shell-side being connected to said first stage pulse tube, and said second outlet of said shell-side being connected to said second stage regenerator, wherein said common thermal block delivers oscillatory flow of said working fluid from said first stage regenerator to each of said first stage pulse tube and said second stage regenerator. 15. A densifier according to claim 12, said first stage cold heat exchanger being operated at 40-80 K. 16. A densifier according to claim 12, said second stage cold heat exchanger being operated at 8-20 K. 17. A densifier according to claim 5, said acoustic heat engine comprising a regenerator and a hot heat exchanger, said regenerator having a regenerator housing and a first heat absorptive material disposed within said housing, said first heat absorptive material having a heat capacity of at least 400 J/kg-K at about 300 K. 18. A densifier according to claim 17, said first heat absorptive material having a thermal conductivity of not more than 28 W/m-K at 1200 K. 19. A densifier according to claim 17, said first heat absorptive material having a porosity of at least 0.5. 20. A densifier according to claim 17, said first heat absorptive material comprising a plurality of layers of 60-800 mesh stainless steel screen. 21. A densifier according to claim 1, said first stage refrigeration unit comprising a first stage regenerator, a first stage cold heat exchanger and a first stage pulse tube, said first stage regenerator having a first stage regenerator housing and a second heat absorptive material disposed within said housing, said second heat absorptive material having a volumetric heat capacity of at least 1 J/cm3K between 60-90 K. 22. A densifier according to claim 21, said second heat absorptive material having a porosity of at least 0.55. 23. A densifier according to claim 21, said second heat absorptive material comprising a plurality of layers of stainless steel screen mesh. 24. A densifier according to claim 1, said second stage refrigeration unit comprising a second stage regenerator, a second stage cold heat exchanger and a second stage pulse tube, said second stage regenerator having a second stage regenerator housing and a third heat absorptive material disposed within said housing, said third heat absorptive material having a volumetric heat capacity of at least 0.23 J/cm3K at 13-14 K. 25. A densifier according to claim 24, said third heat absorptive material having a porosity of 0.2-0.5. 26. A densifier according to claim 24, said third heat absorptive material having a volumetric heat capacity of at least 0.5 J/cm3K at 18-20 K. 27. A densifier according to claim 24, said third heat absorptive material comprising a material selected from the group consisting of rare earth metals and rare earth metal compounds. 28. A densifier according to claim 27, said third heat absorptive material comprising an erbium-praseodymium compound. 29. A densifier according to claim 24, said third heat absorptive material being in the form of spheres having a mean diameter of 60-100 microns. 30. A densifier according to claim 1, wherein said first cryogenic temperature is less than 80 K. 31. A densifier according to claim 1, wherein said second cryogenic temperature is 13-20 K. 32. A densifier according to claim 1, wherein said first cryogenic liquid is liquid oxygen and said second cryogenic liquid is liquid hydrogen. 33. A densifier according to claim 32, wherein said liquid oxygen is supercooled to about 60 K. 34. A densifier according to claim 32, wherein said liquid hydrogen is supercooled to about 13.8 K. 35. A densifier according to claim 1, said densifier being adapted to densify at least one of said first cryogenic liquid and said second cryogenic liquid to a slush cryogenic fluid. 36. A densifier according to claim 1, wherein said resonance tube is 35-55 feet in length. 37. A densifier according to claim 5, wherein said acoustic heat engine is a thermoacoustic Stirling heat engine. 38. A densifier according to claim 5, wherein said acoustic heat engine operates between 700-1300 K. 39. A densifier according to claim 5, wherein said acoustic heat engine is supplied with thermal energy from the combustion of a fuel selected from the group consisting of hydrogen, methane and natural gas. 40. A densifier according to claim 6, wherein said prime mover is a traveling wave acoustical prime mover. 41. A densifier according to claim 1, further comprising a low temperature jacket, said jacket substantially enclosing said pulse tube refrigerator. 42. A densifier according to claim 1, said densifier further comprising a low pressure chamber evacuated to below 10-2 torr. 43. A densifier according to claim 1, said densifier further comprising a secondary heat exchanger and an inert recycle passage, wherein said secondary heat exchanger is connected to said first stage refrigeration unit by said inert recycle passage. 44. A densifier according to claim 5, said oscillatory acoustical power being generated via a working fluid of helium gas, said helium gas having an oscillatory pressure ratio of 1.2-1.4 at an exit of said acoustic heat engine. 45. A densifier according to claim 44, said first stage refrigeration unit comprising a first stage regenerator, a first stage cold heat exchanger, and a first stage pulse tube, wherein said helium gas has an oscillatory pressure ratio of 1-1.3 at an entrance of said first stage pulse tube. 46. A densifier according to claim 1, said oscillatory power having a frequency of about 30 Hz. 47. A densified propellant management system comprising a densifier, and a cryogenic temperature probe, wherein said densifier comprises an oscillatory power source for generating oscillatory power, a resonance tube, and a pulse tube refrigerator, said pulse tube refrigerator being a two-stage pulse tube refrigerator having a first stage refrigeration unit and a second stage refrigeration unit, said first stage refrigeration unit being adapted to supercool a first cryogenic liquid to a first cryogenic temperature, said second stage refrigeration unit being adapted to supercool a second cryogenic liquid to a second cryogenic temperature, wherein said second cryogenic temperature is lower than said first cryogenic temperature. 48. A system according to claim 47, said system further comprising a first cryogenic liquid storage dewar, wherein said cryogenic temperature probe is disposed within said storage dewar and is effective to measure a temperature gradient of said first cryogenic liquid within said storage dewar. 49. A system according to claim 47, wherein said first cryogenic liquid is liquid oxygen and said second cryogenic liquid is liquid hydrogen. 50. A system according to claim 47, wherein said cryogenic temperature probe comprises a dielectric strip and a series of temperature sensing units disposed at spaced intervals along said strip, said temperature sensing units being effective to measure a temperature gradient within a cryogenic liquid. 51. A system according to claim 47, comprising a plurality of said densifiers arranged in a configuration selected from the group consisting of parallel configuration and serial configuration.