Affiliation(s):
Institute of Refrigeration and Cryogenics, Zhejiang University, Hangzhou 310027, China;
moreAffiliation(s): Institute of Refrigeration and Cryogenics, Zhejiang University, Hangzhou 310027, China; Zhejiang Energy Group R& D Institute, Hangzhou 311121, China; Baima Lake Laboratory, Hangzhou 310051, China;
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Jingfeng LI, Kai WANG, Chenjie GU, Limin QIU. An analysis of the exhaust process of cryogenic nitrogen gas from a cryogenic wind tunnel with an inclined exit[J]. Journal of Zhejiang University Science A, 1998, -1(3): .
@article{title="An analysis of the exhaust process of cryogenic nitrogen gas from a cryogenic wind tunnel with an inclined exit", author="Jingfeng LI, Kai WANG, Chenjie GU, Limin QIU", journal="Journal of Zhejiang University Science A", volume="-1", number="-1", pages="", year="1998", publisher="Zhejiang University Press & Springer", doi="10.1631/jzus.A2200289" }
%0 Journal Article %T An analysis of the exhaust process of cryogenic nitrogen gas from a cryogenic wind tunnel with an inclined exit %A Jingfeng LI %A Kai WANG %A Chenjie GU %A Limin QIU %J Journal of Zhejiang University SCIENCE A %V -1 %N -1 %P %@ 1673-565X %D 1998 %I Zhejiang University Press & Springer
TY - JOUR T1 - An analysis of the exhaust process of cryogenic nitrogen gas from a cryogenic wind tunnel with an inclined exit A1 - Jingfeng LI A1 - Kai WANG A1 - Chenjie GU A1 - Limin QIU J0 - Journal of Zhejiang University Science A VL - -1 IS - -1 SP - EP - %@ 1673-565X Y1 - 1998 PB - Zhejiang University Press & Springer ER -
Abstract: During operation of a cryogenic wind tunnel, gravity settlement of large amounts of exhausted cryogenic nitrogen gas can endanger public safety because of the low temperature of the gas and its potential to cause oxygen deficiency. The most effective way to prevent gravity settlement is to raise the temperature of the exhaust to reduce the density of the plume. In a conventional exhaust system with a vertical exit, a fan-ejector is typically used to enhance the mixing of atmospheric air and cryogenic exhaust and burners are used to provide extra heat to raise the exhaust temperature, leading to high energy consumption. Here, we propose a new structural design for the vent stack with an inclined exit to reduce the settlement hazard; it extends the plume trajectory to increase the effective contact space and time for mixing between the plume gas and atmospheric air before the plume settles to the ground, contributing to more efficient energy consumption for heating. Reduced-scale experiments and numerical simulations of plume dispersion based on vertical and 30°-, and 45°-inclined exits were conducted to study harm reduction and energy-saving potential. Analyses of the minimum temperature and minimum oxygen concentration of the plume near the ground indicate that the new exhaust design with an inclined exit clearly reduces the settlement hazard. Under windless conditions and without using a fan-ejector system, up to 15.9% of the heating energy used by the burner can be saved by adopting the new design.
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