Flow Evaluation in the Experimental Chamber for Supersonic Flow in Low Pressures

2018 ◽  
Vol 87 (1) ◽  
pp. 397-403
Author(s):  
Pavla Hlavatá ◽  
Jiří Maxa ◽  
Petr Vyroubal
Keyword(s):  
Supersonic Flow ◽  
Experimental Chamber ◽  
Low Pressures

scholarly journals Application of Prandtl’s Theory in the Design of an Experimental Chamber for Static Pressure Measurements

Sensors ◽  
2021 ◽  
Vol 21 (20) ◽  
pp. 6849
Author(s):  
Pavla Šabacká ◽  
Vilém Neděla ◽  
Jiří Maxa ◽  
Robert Bayer
Keyword(s):  
Supersonic Flow ◽  
Laval Nozzle ◽  
Pressure Sensors ◽  
Small Diameter ◽  
Correct Choice ◽  
Primary Electron ◽  
Experimental Chamber ◽  
State Variables ◽  
Vacuum Chambers ◽  
Low Pressures

Pumping in vacuum chambers is part of the field of environmental electron microscopy. These chambers are separated from each other by a small-diameter aperture that creates a critical flow in the supersonic flow regime. The distribution of pressure and shock waves in the path of the primary electron beam passing through the differentially pumped chamber has a large influence on the quality of the resulting microscope image. As part of this research, an experimental chamber was constructed to map supersonic flow at low pressures. The shape of this chamber was designed using mathematical–physical analyses, which served not only as a basis for the design of its geometry, but especially for the correct choice of absolute and differential pressure sensors with respect to the cryogenic temperature generated in the supersonic flow. The mathematical and physical analyses presented here map the nature of the supersonic flow with large gradients of state variables at low pressures at the continuum mechanics boundary near the region of free molecule motion in which the Environmental Electron Microscope and its differentially pumped chamber operate, which has a significant impact on the resulting sharpness of the final image obtained by the microscope. The results of this work map the flow in and behind the Laval nozzle in the experimental chamber and are the initial basis that enabled the optimization of the design of the chamber based on Prandtl’s theory for the possibility of fitting it with pressure probes in such a way that they can map the flow in and behind the Laval nozzle.

Analysis of the Effect of Reflected Shock Waves in the Experimental Chamber

2021 ◽  
Vol 105 (1) ◽  
pp. 589-599
Author(s):  
Jiří Maxa ◽  
Pavla Šabacká ◽  
Robert Bayer
Keyword(s):  
Electron Microscope ◽  
Supersonic Flow ◽  
Shock Waves ◽  
Vacuum Chamber ◽  
Experimental Chamber ◽  
Scientific Instruments ◽  
Electronic Technology ◽  
Reflected Shock ◽  
University Of Technology ◽  
Flow Through

As part of the research in the field of vacuum chamber pumping in the Environmental Electron Microscope, research on supersonic flow through apertures is being carried out at the Department of Electrical and Electronic Technology of Brno University of Technology in cooperation with the Institute of Scientific Instruments of the CAS. This paper deals with the influence of reflected shock waves on the resulting flow in the pumped part of the Experimental Chamber.

Comparison of the Ansys Fluent System Solvers for the Possibility of Supersonic Flow Solving at the Low Pressures

2019 ◽  
Vol 95 (1) ◽  
pp. 475-481
Author(s):  
Anna Maxová ◽  
Pavla Šabacká ◽  
Jiří Maxa
Keyword(s):  
Supersonic Flow ◽  
Ansys Fluent ◽  
Low Pressures

Mathematical and Physical Analysis of the Effect of Conical and Detached Shock Waves at the Tip of a Static Probe in an Experimental Chamber

2021 ◽  
Vol 105 (1) ◽  
pp. 627-635
Author(s):  
Pavla Šabacká ◽  
Jiří Maxa ◽  
Anna Maxová
Keyword(s):  
Supersonic Flow ◽  
Static Pressure ◽  
Experimental Chamber ◽  
Physical Analysis ◽  
Pressure Measurements ◽  
Scientific Instruments ◽  
Electronic Technology ◽  
Vacuum Chambers ◽  
University Of Technology ◽  
Flow Through

As part of the research in the field of pumping vacuum chambers in the Environmental Electron Microscope, research on supersonic flow through apertures is being carried out at the Department of Electrical and Electronic Technology of the Brno University of Technology in cooperation with the Institute of Scientific Instruments of the CAS. This paper deals with the influence of the shape of the static probe cone design for static pressure measurements in the supersonic flow regime in the Experimental Chamber. The cone of the probe has an effect on the shape of the shock wave, which significantly influences the detected static pressure value.

Numerical Studies on Behavior of Lorentz-Force-Applied Boundary Layer in Supersonic Flow

2009 ◽  
Vol 129 (6) ◽  
pp. 831-839
Author(s):  
Keisuke Udagawa ◽  
Sadatake Tomioka ◽  
Hiroyuki Yamasaki
Keyword(s):  
Boundary Layer ◽  
Supersonic Flow ◽  
Lorentz Force ◽  
Numerical Studies
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