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Pulse tube refrigerator
The pulse tube refrigerator (PTR) or pulse tube cryocooler is a developing technology that emerged largely in the early 1980s with a series of other innovations in the broader field of thermoacoustics. In contrast with other cryocoolers (e.g. Stirling cryocooler and GM-refrigerators), this cryocooler can be made without moving parts in the low temperature part of the device, making the cooler suitable for a wide variety of applications.
Pulse tube cryocoolers are used in niche industrial applications such as semiconductor fabrication and superconducting radio-frequency circuits. They are also used in military applications such as for the cooling of infrared sensors.
In research, PTRs are often used as precoolers of dilution refrigerators. They are also being developed for cooling of astronomical detectors where liquid cryogens are typically used, such as the Atacama Cosmology Telescope or the Qubic experiment (an interferometer for cosmology studies). Pulse tubes are particularly useful in space-based telescopes such as the James Webb Space Telescope where it is not possible to replenish the cryogens as they are depleted. It has also been suggested that pulse tubes could be used to liquefy oxygen on Mars.
Figure 1 represents the Stirling-type single-orifice pulse-tube refrigerator (PTR), which is filled with a gas, typically helium at a pressure varying from 10 to 30 bar. From left to right the components are:
The part in between X1 and X3 is thermally insulated from the surroundings, usually by vacuum. The pressure varies gradually and the velocities of the gas are low. So the name "pulse" tube cooler is misleading, since there are no pulses in the system.
The piston moves periodically from left to right and back. As a result, the gas also moves from left to right and back while the pressure within the system increases and decreases. If the gas from the compressor space moves to the right, it enters the regenerator with temperature TH and leaves the regenerator at the cold end with temperature TL, hence heat is transferred into the regenerator material. On its return, the heat stored within the regenerator is transferred back into the gas.
In the tube, the gas is thermally isolated (adiabatic), so the temperature of the gas in the tube varies with the pressure.
At the cold end of the tube, the gas enters the tube via X2 when the pressure is high with temperature TL and returns when the pressure is low with a temperature below TL, hence taking up heat from X2: this gives the desired cooling effect at X2.
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Pulse tube refrigerator AI simulator
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Pulse tube refrigerator
The pulse tube refrigerator (PTR) or pulse tube cryocooler is a developing technology that emerged largely in the early 1980s with a series of other innovations in the broader field of thermoacoustics. In contrast with other cryocoolers (e.g. Stirling cryocooler and GM-refrigerators), this cryocooler can be made without moving parts in the low temperature part of the device, making the cooler suitable for a wide variety of applications.
Pulse tube cryocoolers are used in niche industrial applications such as semiconductor fabrication and superconducting radio-frequency circuits. They are also used in military applications such as for the cooling of infrared sensors.
In research, PTRs are often used as precoolers of dilution refrigerators. They are also being developed for cooling of astronomical detectors where liquid cryogens are typically used, such as the Atacama Cosmology Telescope or the Qubic experiment (an interferometer for cosmology studies). Pulse tubes are particularly useful in space-based telescopes such as the James Webb Space Telescope where it is not possible to replenish the cryogens as they are depleted. It has also been suggested that pulse tubes could be used to liquefy oxygen on Mars.
Figure 1 represents the Stirling-type single-orifice pulse-tube refrigerator (PTR), which is filled with a gas, typically helium at a pressure varying from 10 to 30 bar. From left to right the components are:
The part in between X1 and X3 is thermally insulated from the surroundings, usually by vacuum. The pressure varies gradually and the velocities of the gas are low. So the name "pulse" tube cooler is misleading, since there are no pulses in the system.
The piston moves periodically from left to right and back. As a result, the gas also moves from left to right and back while the pressure within the system increases and decreases. If the gas from the compressor space moves to the right, it enters the regenerator with temperature TH and leaves the regenerator at the cold end with temperature TL, hence heat is transferred into the regenerator material. On its return, the heat stored within the regenerator is transferred back into the gas.
In the tube, the gas is thermally isolated (adiabatic), so the temperature of the gas in the tube varies with the pressure.
At the cold end of the tube, the gas enters the tube via X2 when the pressure is high with temperature TL and returns when the pressure is low with a temperature below TL, hence taking up heat from X2: this gives the desired cooling effect at X2.