· Low temperature heat and mass transfer
· Regenerative cryocoolers
· Cryogenic air separation process

Cryogenic principle;

CFD application

Achivements:

A no-load temperature of 4.26 K is achieved through optimizing the operating parameters of a three-stage SPTC, which is the lowest temperature ever obtained by a multi-stage SPTC with He-4, for the first time to demonstrate the feasibility of a three-stage SPTC with He-4 reaching liquid helium temperature. Also He-3 was employed with the help of Giessen Univ. and a no-load temperature of 4.03 K was obtained. The above two are both the lowest temperature ever obtained by SPTCs with similar structure.

Main researches:

1) Multi-stage Stirling pulse tube cryocoolers

2) Thermodynamic behaviors of the fluid in cryogenic oscillating flow

3) Cryogenic condensation and evaporation

1) Zhi, X. Q.; Qiu, L. M.*; Pfotenhauer, J. M.; Gan, Z. H.; Yan, Y., Refrigeration mechanism of the gas parcels in pulse tube cryocoolers under different phase angles, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 2016-12, 103, , 382-389

2) Zhi, X. Q.; Han, L.; Dietrich, M.; Gan, Z. H.; Qiu, L. M.*; Thummes, G. A three-stage Stirling pulse tube cryocooler reached 4.26 K with He-4 working fluid, cryogenics, 2013-12, 58, , 93-96

3) X.Q. Zhi; J.M. Pfotenhauer*; F. Miller; V. Gershtein, Numerical study on the working performance of a G-M cryocooler with a mechanically driven displacer, International Journal of Heat and Mass Transfer, 2017-12, 115, 611-618, 2017, 3.552

4) Kim, K.S; Zhi, X.Q*; Qiu, L.M; Nie, H.L; Wang, J.J, Numerical analysis of different valve effects on the cooling performance of a two-stage GM type pulse tube cryocooler, International journal of refrigeration, 2017-05, 77, 1-10

5）Wenjie Zhou, John M. Pfotenhauer, Xiaoqin Zhi*. Leakage effect analysis on the performance of a cylindrical adjustable inertance tube，Cryogenics，2018-04，91，136–141

6）Zhu Jiakai, Wang Shunhao, Qiu Limin, Zhi Xiaoqin*, Zhang Xiaobin*. Frequency characteristics of liquid hydrogen cavitating flow over a NACA0015 hydrofoil, Cryogenics, 2018-12, 90, 7–19.

7）Xiaokuan You, Limin Qiu, Chaoxiang Duan, Xiao Jiang, Chen Huang, Xiaoqin Zhi*, Study on the stroke amplitude of the linear compressor, Applied thermal energy, 2018, 129, 1488–1495.

8）Xiao Jiang, Limin Qiu, Chaoxiang Duan, Xiaokuan You, Xiaoqin Zhi*, An approach for estimating acoustic power in a pulse tube cryocooler，Cryogenics , 2017-04, 87, 103–109

9) Chen Huang, Qiang Cao, Xiaoqin Zhi*, Xi Xia, Limin Qiu. Effects of DC flow on pulse tube cryocooler working at liquid hydrogen and liquid nitrogen temperatures, Applied thermal energy, 2018, 137, 451–460.

10) Qiu, L. M.; Han, L.; Zhi, X. Q.; Dietrich, M.; Gan, Z.H.*; Thummes, G., Investigation on phase shifting for a 4 K Stirling pulse tube cryocooler with He-3 as working fluid, CRYOGENICS, 2015-07, 69， 44-49

11） Qiu, L. M.; Zhi, X. Q.; Gan, Z. H.; Zhang, X. B*.; Zhang, X. J., Function of gas parcels in the pulse tube, International Journal of Refrigeration, 2014-02, 38, 358-366

12） Qiu, L. M.; Zhi, X. Q.; Han, L.; Cao, Q.; Gan, Z. H*, Performance improvement of multi-stage pulse tube cryocoolers with a self-precooled pulse tube, CRYOGENICS, 2012-10, 52, 575-579

13）Qiu, L. M.; Cao, Q.; Zhi, X. Q.; Gan, Z. H.*; Yu, Y. B.; Liu, Y., A three-stage Stirling pulse tube cryocooler operating below the critical point of helium-4, CRYOGENICS, 2011-10, 51, 609-612

14）Yan，Y；Ni，Z.H*；Zhi，X.Q；Yin，J.S, Numerical study on thermal performance of a BOG heat exchanger in the inclined condition, Journal of Natural Gas Science & Engineering, 2016-08, 34,  616-626
15）Cao, Q.; Qiu, L. M.; Zhi, X. Q.; Han, L.; Gan, Z. H.; Zhang, X. B.; Zhang, X. J.*; Sun, D. M., Impedance magnitude optimization of the regenerator in Stirling pulse tube cryocoolers working at liquid-helium temperatures, CRYOGENICS, 2013-12, 58, 38-44
16）Qiu, L. M.; Cao, Q.; Zhi, X. Q.; Han, L.; Gan, Z. H.*; Yu, Y. B.; Liu, Y.; Zhang, X. J.; Pfotenhauer, J. M., Operating characteristics of a three-stage Stirling pulse tube cryocooler operating around 5 K,cryogenics, 2012-09, 52, 382-388

2015.08  The "Carl von Linde" award, International institute of Refrigeration

2015.04  Best paper award, The Chinese Association of Refrigeration

2017.07   Best paper award of 2017 CEC-ICMC hold in Madison