1School of Electronics Engineering, KIIT University, Bhubaneswar, India-751024
2Cryogenic Engineering Centre, Indian Institute of Technology, Kharagpur, India-721101
An immediate effect of pulsed heat load in helium refrigerators used in fusion devices is high fluctuation in return stream, which often leads to instability in plant operation. In this paper, a technique for mitigation of this fluctuation has been proposed using cold-compressor at the coldest part of the helium refrigerator. The cold-compressor is characterized and performance curves scaled according to the requirement. Mitigation of 75% fluctuation in mass flow rate during low heat load condition is demonstrated using dynamic simulation of the coldest part of the helium refrigerator based on modified Claude cycle. Influence of various cycle parameters on refrigeration capacity and the extent of mitigation of mass flow rate fluctuation have been analyzed and results presented. An optimum discharge pressure of cold-compressor is found to exist at 4.5 bar(a). Limitations of the proposed mitigation scheme are also discussed.
Helium refrigerator, Pulsed heat load, Fusion devices, Cold-compressor, Mitigation technique
