scholarly journals Selective multi-line excitation of isotopologues with similar quantum spectra as a function of gas flow pressure, temperature, and laser pulse spectrum

2021 ◽  
Author(s):  
K. A. Lyakhov ◽  
A. N. Pechen
Keyword(s):  
Laser Pulse ◽  
Gas Flow ◽  
Pulse Spectrum ◽  
Flow Pressure ◽  
Quantum Spectra

scholarly journals Gas System for the ATLAS NSW Micromegas Detectors: Design Aspects and Advanced Validation Methods for their QA/QC

2019 ◽  
Vol 24 ◽  
pp. 23 ◽  
Author(s):  
T. Alexopoulos ◽  
E. Gazis ◽  
S. Maltezos ◽  
A. Antoniou ◽  
V. Gika ◽  
...  
Keyword(s):  
Distribution System ◽  
Gas Flow ◽  
Test Methods ◽  
Gas Leak ◽  
Gas System ◽  
Medical Needles ◽  
Flow Pressure ◽  
Loss Method ◽  
Lock In ◽  
Rate Loss

In this work we present the design aspects of the Gas Distribution System of NSW Micromegas detectors, simulation results and gas flow / pressure uniformity. We also describe the appropriate gas leak test methods, a conventional and an alternative one, being used in the Quality Assurance and Quality Control of the detectors. For the performance studies we used emulated leak branches based on medical needles. We also describe proposed upgrade stages combining the proposed competitive Flow Rate Loss method with the Lock-in Amplifier technique. Further, we describe the baseline setup for the Gas Tightness Station at BB5/CERN.

Reverse Flow Pressure Limiting Aperture

2000 ◽  
Vol 6 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Gerasimos D. Danilatos
Keyword(s):  
Pressure Difference ◽  
Gas Flow ◽  
Reverse Flow ◽  
Gas Jet ◽  
The Third ◽  
The Core ◽  
Annular Aperture ◽  
Flow Through ◽  
Flow Pressure ◽  
Gas Molecules

The reverse flow pressure limiting aperture is a device that creates and sustains a substantial gas pressure difference between two chambers connected via an aperture. The aperture is surrounded by an annular orifice leading to a third chamber. The third chamber is maintained at a relatively high pressure that forces gas to flow through the annular aperture into the first of said two chambers. The ensuing gas flow develops into a supersonic annular gas jet, the core of which is coaxial with the central aperture. A pumping action is created at the core of the jet and any gas molecules leaking through the aperture from the second chamber are entrained and forced into the first chamber, thus creating a substantial pressure difference between the first and second chamber.

DSMC Simulation of Supersonic Gas Flow in Microchannel

2011 ◽  
Author(s):  
Mohamad M. Joneidipour ◽  
Reza Kamali
Keyword(s):  
Gas Flow ◽  
Characteristic Length ◽  
Flow Characteristics ◽  
Mean Free Path ◽  
Incoming Flow ◽  
Characteristic Length Scale ◽  
Flow Pressure ◽  
Supersonic Gas Flow ◽  
The Mean ◽  
Gas Molecules

The present study is concerned with the flow characteristics of a microchannel supersonic gas flow. The direct simulation Monte Carlo (DSMC) method is employed for predicting the density, velocity and temperature distributions. For gas flows in micro systems, the continuum hypothesis, which underpins the Navier-Stokes equations, may be inappropriate. This is because the mean free path of the gas molecules may be comparable to the characteristic length scale of the device. The Knudsen number, Kn, which is the ratio of the mean free path of the gas molecules to the characteristic length scale of the device, is a convenient measure of the degree of rarefaction of the flow. In this paper, the effect of Knudsen number on supersonic microchannel flow characteristics is studied by varying the incoming flow pressure or the microchannel height. In addition, the microchannel height and the incoming flow pressure are varied simultaneously to investigate their effects on the flow characteristics. Meanwhile, the results show that until the diffuse reflection model is used throughout the microchannel, the temperature and the Mach number in the microchannel entrance may not be equal to free-stream values and therefore a discontinuity appear in the flow field.

Research on the Correction of Regeneration Opportunity of DPF Using GW4D20 Engine

2014 ◽  
Vol 989-994 ◽  
pp. 3161-3164
Author(s):  
Shi Jie Qiao ◽  
Yu Liu
Keyword(s):  
Pressure Drop ◽  
Control Method ◽  
Temperature Correction ◽  
Back Pressure ◽  
Two Dimensional ◽  
Pulse Spectrum ◽  
Practical Application ◽  
Key Factor ◽  
Flow Pressure

The accurate diagnose of the timing of regeneration is the key factor of solving the problem that the filter body is damaged and the process of regeneration is uncomplete. The timing of regeneration judged by the exhaust back pressure is a type of widely accepted control method, the essence of which means to estimate whether the quantity of particle in the filter can fulfil the demand of regeneration or not. In the process of practical application, this kind of method is influenced by the engine conditions, therefore, we must monitor the engine at any moment by speed and load of signal acquisition.In this article,it summarizes two dimensional pulse spectrum" exhaust flow--pressure drop” through universal characteristics test. Meanwhile it conducts the temperature correction in order to simplify the complexity of the judge-ment of regeneration opportunity.

Reverse Flow Pressure Limiting Aperture

2000 ◽  
Vol 6 (1) ◽  
pp. 21-30
Author(s):  
Gerasimos D. Danilatos
Keyword(s):  
Pressure Difference ◽  
Gas Flow ◽  
Reverse Flow ◽  
Gas Jet ◽  
The Third ◽  
The Core ◽  
Annular Aperture ◽  
Flow Through ◽  
Flow Pressure ◽  
Gas Molecules

Abstract The reverse flow pressure limiting aperture is a device that creates and sustains a substantial gas pressure difference between two chambers connected via an aperture. The aperture is surrounded by an annular orifice leading to a third chamber. The third chamber is maintained at a relatively high pressure that forces gas to flow through the annular aperture into the first of said two chambers. The ensuing gas flow develops into a supersonic annular gas jet, the core of which is coaxial with the central aperture. A pumping action is created at the core of the jet and any gas molecules leaking through the aperture from the second chamber are entrained and forced into the first chamber, thus creating a substantial pressure difference between the first and second chamber.

Study on Characteristics of Gas Flow in Catalytic Converter with Different Outlet Diameters

2014 ◽  
Vol 711 ◽  
pp. 16-19
Author(s):  
Zhan Jun Cai ◽  
Wei Min Kang ◽  
Ya Bin Li
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Catalytic Reaction ◽  
Gas Flow ◽  
Static Pressure ◽  
Catalytic Converter ◽  
Geometric Model ◽  
Flow Pressure ◽  
Different Diameters ◽  
Dynamics Method

. This paper studies the different diameters of tube outlet how to affect the gas flow pressure and velocity distribution in nanofiber catalytic converter by CFD (Computational Fluid Dynamics) method. Geometric model of the catalytic converter has been established and meshed by the pre-processing tool of FLUENT. The distribution of velocity and pressure in the converter which outlet diameter is 70 mm is more evenly than the converter which outlet diameter is 50 mm. It is conducive to reducing airflow static pressure in the catalytic converter that expanding the outlet diameter in the case of other conditions remains unchanged. Therefore, the larger outlet diameter is beneficial to exhaust catalytic reaction.

Steady pressure-flow relationship of a model of the canine bronchial tree

1981 ◽  
Vol 51 (5) ◽  
pp. 1072-1079 ◽  
Author(s):  
D. B. Reynolds ◽  
J. S. Lee
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Kinetic Energy ◽  
Total Pressure ◽  
Gas Flow ◽  
Static Pressure ◽  
Bronchial Tree ◽  
Flow Pressure ◽  
Expiratory Flow ◽  
Relationship Of

Static pressure differences (deltaP) across the entire length and portions of a latex reproduction of a canine bronchial tree were measured during steady inspiratory or expiratory flow (V). The reproduction consists of a 10-cm length of trachea through bronchi of about 2 mm in diameter. The airflow was simulated by a water flow with tracheal Renolds number (Re0) in the range from 1,500 to 10,000. Loss in total pressure (deltaPt) was computed by summing deltaPt and V were well described (r greater than 0.98) by a dimensionless Rohrer equation deltaPt/deltaPd0 = A + B Re0 applicable to gas flow, in which deltaPd0 is a Poiseuille pressure drop. For expiratory deltaPt, A was about twice that for inspiration, while the values for B were nearly equal. Differences in kinetic energy between sites of static pressure measurement are important in determining loss in total pressure. Rohrer's equation is a good approximation to the phenomenological laws of steady inspiratory and expiratory flow-pressure relations in the canine bronchial tree for the range of Reynolds number investigated.

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