Investigation on pulse tube/J-T hybrid cryocooler capable of fast cool down.

In many special applications such as the infrared guidance system, the cool down time and the life of the cryocoolers are strictly limited simultaneously. Due to the unsatisfactory behaviors of the conventional cryocoolers, a new system which combines a pulse tube cryocooler with an open-cycle J-T cooler is set up. A theoretical model of the hybrid system is set up, the working principles are analyzed. And a non-dimensional correlation is developed to investigate the mutual relations between the intrinsic parameters. For the pulse tube cryocooler, the size is limited by the largest cooling capacity of the J-T cooler. And for the latter one, its performance is mainly determined by the cut off time, initial pressure, total heat load, volume of the cylinder and exhausted pressure.