Computational Studies on Flow Through De Laval Nozzle

Black hole accretion is necessarily transonic and the number of physical sonic points depends on the angular momentum of the flow. We study the properties of such a flow by recasting this idea into an engineering problem in which a flow has a subsonic to supersonic transition when it passes through a de Laval nozzle, i.e. a converging and diverging duct in a flat geometry in the presence of sufficient end pressure difference. Particularly interesting is the case of the centrifugal pressure supported standing shock formation inside an accretion flow, because the flow passes through at least two saddle type sonic points, one before and one after the shock. In this case, the duct itself has two minima and a maximum. We study the properties of such a duct as a function of the inflow parameters and classify all possible types of the flow through this composite nozzle.

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Numerical Solution of Internal Flow through a de Laval Nozzle Based on the Euler Model with the SU2 Code: Verification and Validation

10.26678/abcm.encit2020.cit20-0426 ◽

2020 ◽

Author(s):

Giovanne Deni Iorio ◽

Guilherme Bertoldo ◽

Carlos Henrique Marchi

Keyword(s):

Numerical Solution ◽

Laval Nozzle ◽

Internal Flow ◽

Verification And Validation ◽

Code Verification ◽

De Laval Nozzle ◽

Euler Model ◽

Flow Through

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An improved de Laval nozzle experiment

International Journal of Mechanical Engineering Education ◽

10.1177/03064190211034165 ◽

2021 ◽

pp. 030641902110341

Author(s):

Nicholas Goodman ◽

Brian J Leege ◽

Peter E Johnson

Keyword(s):

Data Acquisition ◽

Laval Nozzle ◽

Flow Characteristics ◽

Data Acquisition System ◽

Isentropic Flow ◽

Hands On ◽

De Laval Nozzle ◽

Physical Phenomena ◽

The Impact ◽

The Relationship

Exposing students to hands-on experiments has been a common approach to illustrating complex physical phenomena that have been otherwise modelled solely mathematically. Compressible, isentropic flow in a duct is an example of such a phenomenon, and it is often demonstrated via a de Laval nozzle experiment. We have improved an existing converging/diverging nozzle experiment so that students can modify the location of the normal shock that develops in the diverging portion to better understand the relationship between the shock and the pressure. We have also improved the data acquisition system for this experiment and explained how visualisation of the standing shock is now possible. The results of the updated system demonstrate that the accuracy of the isentropic flow characteristics has not been lost. Through pre- and post-laboratory quizzes, we show the impact on student learning as well.

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Effect of Gas Pressure and Temperature on Stereometric Properties of Al+Al2O3 Composite Coatings Deposited by LPCS Method

Archives of Metallurgy and Materials ◽

10.2478/amm-2014-0149 ◽

2014 ◽

Vol 59 (3) ◽

pp. 879-886 ◽

Cited By ~ 3

Author(s):

M. Winnicki ◽

T. Piwowarczyk ◽

A. Małachowska ◽

A. Ambroziak

Keyword(s):

Laval Nozzle ◽

Composite Coatings ◽

Gas Pressure ◽

Feedstock Powder ◽

Substrate Distance ◽

Al2o3 Composite ◽

Spray Method ◽

Powder Mass ◽

De Laval Nozzle ◽

Temperature And Pressure

Abstract The paper deals with effect of working gas pressure and temperature on surface stereometry of coatings deposited by low-pressure cold spray method. Examinations were focused on aluminium coatings which are commonly used to protect substrate against corrosion. A commercial Al spherical feedstock powder with admixture of Al2O3 (Al + 60vol.-% Al2O3), granulation -50+10 µm, was used to coat steel, grade S235JR. Thedeposited coatings were studied to determine their stereometry, i.e. roughness, transverse and longitudinal waviness, topography of surface and thickness as the functions of gas pressure and temperature. A profilometer and focal microscope were used to evaluate the stereometric properties. In order to reduce the number of variables, the remaining process parameters, i.e. shape and size of de Laval nozzle, nozzle-to-substrate distance, powder mass flow rate, linear velocity of spraying gun, were kept unchanged. The investigation confirmed influence of temperature and pressure on coating thickness as well as on the surface seterometry.

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