Cargando…

Experimental Investigation and Theoretical Modelling of a High-Pressure Pneumatic Catapult Considering Dynamic Leakage and Convection

A high-pressure pneumatic catapult works under extreme boundaries such as high-pressure and rapid change of pressure and temperature, with the features of nonlinearity and gas-solid convection. In the thermodynamics processes, the pressure is much larger than the critical pressure, and the compressi...

Descripción completa

Detalles Bibliográficos
Autores principales: Ren, Jie, Zhong, Jianlin, Yao, Lin, Guan, Zhongwei
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7597084/
https://www.ncbi.nlm.nih.gov/pubmed/33286779
http://dx.doi.org/10.3390/e22091010
_version_ 1783602256964222976
author Ren, Jie
Zhong, Jianlin
Yao, Lin
Guan, Zhongwei
author_facet Ren, Jie
Zhong, Jianlin
Yao, Lin
Guan, Zhongwei
author_sort Ren, Jie
collection PubMed
description A high-pressure pneumatic catapult works under extreme boundaries such as high-pressure and rapid change of pressure and temperature, with the features of nonlinearity and gas-solid convection. In the thermodynamics processes, the pressure is much larger than the critical pressure, and the compressibility factor can deviate from the Zeno line significantly. Therefore, the pneumatic performance and thermo-physical properties need to be described with the real gas hypothesis instead of the ideal gas one. It is found that the analytical results based on the ideal gas model overestimate the performance of the catapult, in comparison to the test data. To obtain a theoretical model with dynamic leakage compensation, leakage tests are carried out, and the relationship among the leakage rate, pressure and stroke is fitted. The compressibility factor library of the equation of state for compressed air is established and evaluated by referring it to the Nelson-Obert generalized compressibility charts. Based on the Peng–Robinson equation, a theoretical model of the high-pressure pneumatic catapult is developed, in which the effects of dynamic leakage and the forced convective heat transfer between the gas and the metal wall are taken into account. The results from the theoretical model are consistent with the data from ejection tests. This research presents an approach to study the performance of a high-pressure pneumatic catapult with high precision.
format Online
Article
Text
id pubmed-7597084
institution National Center for Biotechnology Information
language English
publishDate 2020
publisher MDPI
record_format MEDLINE/PubMed
spelling pubmed-75970842020-11-09 Experimental Investigation and Theoretical Modelling of a High-Pressure Pneumatic Catapult Considering Dynamic Leakage and Convection Ren, Jie Zhong, Jianlin Yao, Lin Guan, Zhongwei Entropy (Basel) Article A high-pressure pneumatic catapult works under extreme boundaries such as high-pressure and rapid change of pressure and temperature, with the features of nonlinearity and gas-solid convection. In the thermodynamics processes, the pressure is much larger than the critical pressure, and the compressibility factor can deviate from the Zeno line significantly. Therefore, the pneumatic performance and thermo-physical properties need to be described with the real gas hypothesis instead of the ideal gas one. It is found that the analytical results based on the ideal gas model overestimate the performance of the catapult, in comparison to the test data. To obtain a theoretical model with dynamic leakage compensation, leakage tests are carried out, and the relationship among the leakage rate, pressure and stroke is fitted. The compressibility factor library of the equation of state for compressed air is established and evaluated by referring it to the Nelson-Obert generalized compressibility charts. Based on the Peng–Robinson equation, a theoretical model of the high-pressure pneumatic catapult is developed, in which the effects of dynamic leakage and the forced convective heat transfer between the gas and the metal wall are taken into account. The results from the theoretical model are consistent with the data from ejection tests. This research presents an approach to study the performance of a high-pressure pneumatic catapult with high precision. MDPI 2020-09-10 /pmc/articles/PMC7597084/ /pubmed/33286779 http://dx.doi.org/10.3390/e22091010 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Ren, Jie
Zhong, Jianlin
Yao, Lin
Guan, Zhongwei
Experimental Investigation and Theoretical Modelling of a High-Pressure Pneumatic Catapult Considering Dynamic Leakage and Convection
title Experimental Investigation and Theoretical Modelling of a High-Pressure Pneumatic Catapult Considering Dynamic Leakage and Convection
title_full Experimental Investigation and Theoretical Modelling of a High-Pressure Pneumatic Catapult Considering Dynamic Leakage and Convection
title_fullStr Experimental Investigation and Theoretical Modelling of a High-Pressure Pneumatic Catapult Considering Dynamic Leakage and Convection
title_full_unstemmed Experimental Investigation and Theoretical Modelling of a High-Pressure Pneumatic Catapult Considering Dynamic Leakage and Convection
title_short Experimental Investigation and Theoretical Modelling of a High-Pressure Pneumatic Catapult Considering Dynamic Leakage and Convection
title_sort experimental investigation and theoretical modelling of a high-pressure pneumatic catapult considering dynamic leakage and convection
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7597084/
https://www.ncbi.nlm.nih.gov/pubmed/33286779
http://dx.doi.org/10.3390/e22091010
work_keys_str_mv AT renjie experimentalinvestigationandtheoreticalmodellingofahighpressurepneumaticcatapultconsideringdynamicleakageandconvection
AT zhongjianlin experimentalinvestigationandtheoreticalmodellingofahighpressurepneumaticcatapultconsideringdynamicleakageandconvection
AT yaolin experimentalinvestigationandtheoreticalmodellingofahighpressurepneumaticcatapultconsideringdynamicleakageandconvection
AT guanzhongwei experimentalinvestigationandtheoreticalmodellingofahighpressurepneumaticcatapultconsideringdynamicleakageandconvection