Description
Here the so-called Stirling-type single-orifice pulse-tube refrigerator will be treated operating with an ideal gas (helium) as the working fluid. Figure 1 represents the Stirling-type single-orifice Pulse-Tube Refrigerator (PTR). From left to right the components are:
- a compressor, with a piston moving back and forth at room temperature TH;
- a heat exchanger X1 where heat is released to the surroundings;
- a regenerator consisting of a porous medium with a large specific heat,The porous medium can be stainless steel wire mesh, copper wire mesh, phosphor bronze wire mesh or lead balls or lead shots or sometimes may be rarely earthen materials to produce very low temperature;
- a heat exchanger X2 where the useful cooling power is delivered at the low temperature TL;
- a tube, often called "the pulse tube";
- a heat exchanger X3 at room temperature where heat is released to the surroundings;
- a flow resistance (often called orifice);
- a buffer volume (a large closed volume at practically constant pressure).
The part in between X1 and X3 is thermally insulated from the surroundings, usually by vacuum. The cooler is filled with helium at a pressure in the range from 10 to 30 bar. The pressure varies gradually and the velocities of the gas are low. So the name "pulse" tube cooler is very misleading since there are no pulses whatsoever in the system.
Read more about this topic: Pulse Tube Refrigerator
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