scholarly journals Nozzle Wear and Pressure Rise in Heating Volume of Self-blast Type Ultra-high Pressure Nitrogen Arc

2019 ◽  
Vol 6 (1) ◽  
pp. 23-26 ◽  
Author(s):  
F. Abid ◽  
K. Niayesh ◽  
N. S. Støa-Aanensen
Keyword(s):  
High Pressure ◽  
Mass Loss ◽  
Pressure Rise ◽  
Filling Pressure ◽  
Electrode Gap ◽  
Ultra High Pressure ◽  
Unit Energy ◽  
Nozzle Wear ◽  
Type Switch ◽  
Current Zero

This paper reports on experiments with ultra-high pressure nitrogen arcs in a self-blast type switch design. The effect of filling pressure on nozzle mass loss and pressure-rise in the heating volume were investigated. An arc current peak of 130 A at 190 Hz and a fixed inter-electrode gap of 50 mm were used throughout the experiment. The arc burns inside a polytetrafluoroethylene nozzle with a gas outflow vent in the middle. Nitrogen filling pressure of 1 bar, 20 bar, and 40 bar was tested, which also covers the supercritical region. Moreover, to study the effect of vent size on blow pressure near current zero, three different vent dimensions were investigated. <span> By increasing the filling pressure, the energy deposited in the arc increases as a result of increased arcing voltage</span>. It was observed that the pressure-rise in the heating volume is linked to the filling pressure, while the vent size plays a crucial role in the blow pressure near current zero. The nozzle mass loss per unit energy deposited in the arc is found to be independent of the filling pressure.

scholarly journals Trans-lithospheric diapirism explains the presence of ultra-high pressure rocks in the European Variscides

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Petra Maierová ◽  
Karel Schulmann ◽  
Pavla Štípská ◽  
Taras Gerya ◽  
Ondrej Lexa
Keyword(s):  
High Pressure ◽  
Numerical Models ◽  
Classical Concept ◽  
Plate Interface ◽  
Ultra High Pressure ◽  
Common Process ◽  
Mountain Belts ◽  
Collisional Orogens ◽  
Rock Association ◽  
European Variscides

AbstractThe classical concept of collisional orogens suggests that mountain belts form as a crustal wedge between the downgoing and overriding plates. However, this orogenic style is not compatible with the presence of (ultra-)high pressure crustal and mantle rocks far from the plate interface in the Bohemian Massif of Central Europe. Here we use a comparison between geological observations and thermo-mechanical numerical models to explain their formation. We suggest that continental crust was first deeply subducted, then flowed laterally underneath the lithosphere and eventually rose in the form of large partially molten trans-lithospheric diapirs. We further show that trans-lithospheric diapirism produces a specific rock association of (ultra-)high pressure crustal and mantle rocks and ultra-potassic magmas that alternates with the less metamorphosed rocks of the upper plate. Similar rock associations have been described in other convergent zones, both modern and ancient. We speculate that trans-lithospheric diapirism could be a common process.

scholarly journals Advances in ultra‐high‐pressure and multi‐dimensional liquid chromatography instrumentation and workflows

2021 ◽  
Author(s):  
Jelle De Vos ◽  
Dwight Stoll ◽  
Stephan Buckenmaier ◽  
Sebastiaan Eeltink ◽  
James P. Grinias
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
Ultra High Pressure

Roles of vanes in diffuser on stability of centrifugal compressor

2019 ◽  
Vol 233 (14) ◽  
pp. 5380-5392
Author(s):  
Wangzhi Zou ◽  
Xiao He ◽  
Wenchao Zhang ◽  
Zitian Niu ◽  
Xinqian Zheng
Keyword(s):  
High Pressure ◽  
Centrifugal Compressor ◽  
Dynamic Pressure ◽  
Pressure Ratio ◽  
Pressure Rise ◽  
Rotating Stall ◽  
Centrifugal Compressors ◽  
Compression System ◽  
The Stability ◽  
Rotating Instability

The stability considerations of centrifugal compressors become increasingly severe with the high pressure ratios, especially in aero-engines. Diffuser is the major subcomponent of centrifugal compressor, and its performance greatly influences the stability of compressor. This paper experimentally investigates the roles of vanes in diffuser on component instability and compression system instability. High pressure ratio centrifugal compressors with and without vanes in diffuser are tested and analyzed. Rig tests are carried out to obtain the compressor performance map. Dynamic pressure measurements and relevant Fourier analysis are performed to identify complex instability phenomena in the time domain and frequency domain, including rotating instability, stall, and surge. For component instability, vanes in diffuser are capable of suppressing the emergence of rotating stall in the diffuser at full speeds, but barely affect the characteristics of rotating instability in the impeller at low and middle speeds. For compression system instability, it is shown that the use of vanes in diffuser can effectively postpone the occurrence of compression system surge at full speeds. According to the experimental results and the one-dimensional flow theory, vanes in diffuser turn the diffuser pressure rise slope more negative and thus improve the stability of compressor stage, which means lower surge mass flow rate.

Impact of ultra high pressure on microbial characteristics of rose pomace beverage: A comparative study against conventional heat pasteurization

LWT ◽  
2020 ◽  
Vol 127 ◽  
pp. 109395
Author(s):  
Xu Wang ◽  
Xinyu Zhai ◽  
Haoran Zhang ◽  
Xiaoyu Zhang ◽  
Difeng Ren ◽  
...  
Keyword(s):  
High Pressure ◽  
Comparative Study ◽  
Ultra High Pressure ◽  
Microbial Characteristics ◽  
Heat Pasteurization
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