Relaxation Effects in Small Critical NozzlesSource: Journal of Fluids Engineering:;2006:;volume( 128 ):;issue: 001::page 170DOI: 10.1115/1.2137346Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: We computed the flow of four gases (He, N2, CO2, and SF6) through a critical flow venturi (CFV) by augmenting traditional computational fluid dynamics (CFD) with a rate equation that accounts for τrelax, a species-dependent relaxation time that characterizes the equilibration of the vibrational degrees of freedom with the translational and rotational degrees of freedom. Conventional CFD (τrelax=0) underpredicts the flow through small CFVs (throat diameter d=0.593mm) by up to 2.3% for CO2 and by up to 1.2% for SF6. When we used values of τrelax from the acoustics literature, the augmented CFD underpredicted the flow for SF6 by only 0.3%, in the worst case. The augmented predictions for CO2 were within the scatter of previously published experimental data (±0.1%). As expected, both conventional and augmented CFD agree with experiments for He and N2. Thus, augmented CFD enables one to calibrate a small CFV with one gas (e.g., N2) and to use these results as a flow standard with other gases (e.g., CO2) for which reliable values of τrelax and the relaxing heat capacity are available.
keyword(s): Flow (Dynamics) , Relaxation (Physics) , Computational fluid dynamics , Equations , Gases , Discharge coefficient , Temperature , Equilibrium (Physics) , Navier-Stokes equations , Geometry AND Nozzles ,
|
Collections
Show full item record
contributor author | Aaron N. Johnson | |
contributor author | Charles L. Merkle | |
contributor author | Michael R. Moldover | |
contributor author | John D. Wright | |
date accessioned | 2017-05-09T00:20:27Z | |
date available | 2017-05-09T00:20:27Z | |
date copyright | January, 2006 | |
date issued | 2006 | |
identifier issn | 0098-2202 | |
identifier other | JFEGA4-27214#170_1.pdf | |
identifier uri | http://yetl.yabesh.ir/yetl/handle/yetl/134013 | |
description abstract | We computed the flow of four gases (He, N2, CO2, and SF6) through a critical flow venturi (CFV) by augmenting traditional computational fluid dynamics (CFD) with a rate equation that accounts for τrelax, a species-dependent relaxation time that characterizes the equilibration of the vibrational degrees of freedom with the translational and rotational degrees of freedom. Conventional CFD (τrelax=0) underpredicts the flow through small CFVs (throat diameter d=0.593mm) by up to 2.3% for CO2 and by up to 1.2% for SF6. When we used values of τrelax from the acoustics literature, the augmented CFD underpredicted the flow for SF6 by only 0.3%, in the worst case. The augmented predictions for CO2 were within the scatter of previously published experimental data (±0.1%). As expected, both conventional and augmented CFD agree with experiments for He and N2. Thus, augmented CFD enables one to calibrate a small CFV with one gas (e.g., N2) and to use these results as a flow standard with other gases (e.g., CO2) for which reliable values of τrelax and the relaxing heat capacity are available. | |
publisher | The American Society of Mechanical Engineers (ASME) | |
title | Relaxation Effects in Small Critical Nozzles | |
type | Journal Paper | |
journal volume | 128 | |
journal issue | 1 | |
journal title | Journal of Fluids Engineering | |
identifier doi | 10.1115/1.2137346 | |
journal fristpage | 170 | |
journal lastpage | 176 | |
identifier eissn | 1528-901X | |
keywords | Flow (Dynamics) | |
keywords | Relaxation (Physics) | |
keywords | Computational fluid dynamics | |
keywords | Equations | |
keywords | Gases | |
keywords | Discharge coefficient | |
keywords | Temperature | |
keywords | Equilibrium (Physics) | |
keywords | Navier-Stokes equations | |
keywords | Geometry AND Nozzles | |
tree | Journal of Fluids Engineering:;2006:;volume( 128 ):;issue: 001 | |
contenttype | Fulltext |