Publication detail

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

ŠABACKÁ, P. NEDĚLA, V. MAXA, J. BAYER, R.

Original Title

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

Type

journal article in Web of Science

Language

English

Original Abstract

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.

Keywords

BD sensor; Differentially pumped chamber; ESEM; Mach number; Prandtl’s theory; Static pressure; Static probe

Authors

ŠABACKÁ, P.; NEDĚLA, V.; MAXA, J.; BAYER, R.

Released

2. 9. 2021

Publisher

MDPI

Location

BASEL

ISBN

1424-8220

Periodical

SENSORS

Year of study

21

Number

20

State

Swiss Confederation

Pages from

1

Pages to

13

Pages count

13

URL

https://www.mdpi.com/1424-8220/21/20/6849

Full text in the Digital Library

http://hdl.handle.net/11012/202249

BibTex

@article{BUT172956,
  author="Pavla {Šabacká} and Vilém {Neděla} and Jiří {Maxa} and Robert {Bayer}",
  title="Application of Prandtl’s Theory in the Design of an Experimental Chamber for Static Pressure Measurements",
  journal="SENSORS",
  year="2021",
  volume="21",
  number="20",
  pages="1--13",
  doi="10.3390/s21206849",
  issn="1424-8220",
  url="https://www.mdpi.com/1424-8220/21/20/6849"
}