| 摘要 |
A cold head 2 for a pulse tube cooler has a regenerator 4, a pulse tube 14, and a heat exchanger 10 connected therebetween. The heat exchanger connects between a first end 12 of the pulse tube and a second end 8 of the regenerator, and a first end of the regenerator 6 is connectable to a compressor. A phase control device is connected to a second end 16 of the pulse tube, and in use controls flow dynamics (e.g. the relative phases of the pressure and mass flow variations) within the pulse tube to provide cooling at the heat exchanger, thereby maintaining a negative temperature gradient between the first and second ends of the regenerator. The pulse tube has a wall 15 which has a porous portion 28 to for allowing a working gas to enter or leave the pulse tube directly through the porous portion, as indicated by arrows 30. The porous portion is nearer to being parallel than perpendicular to the temperature gradient between the first and second ends of the regenerator. |
