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

Sensors (Basel)

Department of Electrical and Electronic Technology, Brno University of Technology, 61100 Brno, Czech Republic.

Published: October 2021

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.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8538980PMC
http://dx.doi.org/10.3390/s21206849DOI Listing

Publication Analysis

Top Keywords

supersonic flow
16
experimental chamber
12
prandtl's theory
8
environmental electron
8
differentially pumped
8
pumped chamber
8
low pressures
8
map flow
8
flow laval
8
laval nozzle
8

Similar Publications

Suppression of Collision-Induced Dissociation in a Supersonically Expanding Gas.

Anal Chem

January 2025

Department of Physics & CAMOST, IISER Tirupati, Tirupati 517619, Andhra Pradesh, India.

In high-resolution mass spectrometry, an electrospray ionization source is often paired with an ion-funnel to enhance ion transmission. Although it is established that ions experience collision-induced dissociation as they pass through this device, the impact of gas-flow dynamics on ion fragmentation remains unexplored. The present work demonstrates that the gas-flow dynamics from the capillary interface of an electrospray ionization source into an ion-funnel significantly reduces ion fragmentation.

View Article and Find Full Text PDF

This investigation presents extensive computational analyses of the compressible flow near ramp injector with double circular injectors at supersonic combustor of scramjet engine. Comparison of the fuel mixing and fuel jet penetration of hydrogen jet are done for two injector configurations at free stream Mach number of 2. The simulation of the supersonic flow near ramp injector is done via solving RANS equations with computational fluid dynamic technique.

View Article and Find Full Text PDF

Shock wave boundary/layer interactions (SWBLIs) are critical in high-speed aerodynamic flows, particularly within supersonic regimes, where unsteady dynamics can induce structural fatigue and degrade vehicle performance. Conventional measurement techniques, such as pressure-sensitive paint (PSP), face limitations in frequency response, calibration complexity, and intrusive instrumentation. Similarly, MEMS-based sensors, like Kulite sensors, present challenges in terms of intrusiveness, cost, and integration complexity.

View Article and Find Full Text PDF

Analysis of the Influence of Different Diameters of De Laval Supersonic Nozzles on the Key Splashing Parameters of Remaining Slag.

Materials (Basel)

November 2024

Department of Machine Parts and Mechanism, Faculty of Mechanical Engineering, Technical University of Liberec, Studentská Str. 2, 46117 Liberec, Czech Republic.

The paper is devoted to the analysis of a supersonic nozzle system effect in gas-cooled lances on the technological parameters of slag splashing in an oxygen converter. Simulation calculations were carried out, taking into account the parameters of nozzles used in the technological lines of converter steel plants in Ukraine and Brazil. The problems were solved in several stages.

View Article and Find Full Text PDF
Article Synopsis
  • * Copper targets are exposed to laser pulses with energies of 30, 60, and 90 mJ/pulse, revealing various surface structures like micro-cones and droplets through scanning electron microscopy (SEM) and showing structural changes via X-ray diffraction (XRD).
  • * Results show a significant increase in microhardness (2.77 times greater) and a change from tensile to compressive residual stress in the surface layers, indicating that laser treatment can enhance mechanical properties effectively.
View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!