Requirements for a Hybrid Dust-Gas-Standard: Influence of the Mixing Procedure on Safety Characteristics of Hybrid Mixtures
While developing a standard for the determination of safety characteristics for hybrid mixtures the authors discovered, that, beside the ignition source, the mixing procedure is the main difference between the single-phase standards for dusts and gases. The preparation of hybrid mixtures containing...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-08-01
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| Series: | Fire |
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| Online Access: | https://www.mdpi.com/2571-6255/5/4/113 |
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| author | Stefan H. Spitzer Enis Askar Kristin J. Hecht Dieter Gabel Sabine Zakel Arne Krietsch |
| author_facet | Stefan H. Spitzer Enis Askar Kristin J. Hecht Dieter Gabel Sabine Zakel Arne Krietsch |
| author_sort | Stefan H. Spitzer |
| collection | DOAJ |
| description | While developing a standard for the determination of safety characteristics for hybrid mixtures the authors discovered, that, beside the ignition source, the mixing procedure is the main difference between the single-phase standards for dusts and gases. The preparation of hybrid mixtures containing a flammable gas and a flammable dust in the 20 L-sphere can be realized in different ways. Either the flammable gas is filled only in the sphere or only in the dust container or in both. In previous works, almost always the first method is applied, without giving any information on the accuracy of the gas mixtures. In this work the accuracy of the gas mixtures and the results of the tests applying two methods of mixing were studied. No significant influence of the mixing method itself on the safety characteristics explosion pressure p<sub>ex</sub> and the normalized rate of pressure rise (K-value) was found. Obviously, homogenization of the gas mixtures can be obtained sufficiently by the turbulence that is caused during the injection from the dust container into the explosion chamber within a short time. However, the mixing procedure has a great influence on the accuracy of the gas amount of the mixtures obtained. Without modifying the 20 L-sphere by installing precise pressure sensors, assuring its tightness and performing gas analysis, it must be expected, that the accuracy of the gas mixtures is very low. This has a significant influence on the measured safety characteristics and may lead to unsafe facilities or unnecessary expensive safety measures. |
| first_indexed | 2024-03-09T09:57:31Z |
| format | Article |
| id | doaj.art-88d379b3f98040aea8df955cc4e4935f |
| institution | Directory Open Access Journal |
| issn | 2571-6255 |
| language | English |
| last_indexed | 2024-03-09T09:57:31Z |
| publishDate | 2022-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Fire |
| spelling | doaj.art-88d379b3f98040aea8df955cc4e4935f2023-12-01T23:41:13ZengMDPI AGFire2571-62552022-08-015411310.3390/fire5040113Requirements for a Hybrid Dust-Gas-Standard: Influence of the Mixing Procedure on Safety Characteristics of Hybrid MixturesStefan H. Spitzer0Enis Askar1Kristin J. Hecht2Dieter Gabel3Sabine Zakel4Arne Krietsch5Physikalisch Technische Bundesanstalt, 38116 Braunschweig, GermanyBundesanstalt für Materialforschung, 12205 Berlin, GermanyBundesanstalt für Materialforschung, 12205 Berlin, GermanyInstitut für Apparate und Umwelttechnik, Otto von Guericke Universität, 39106 Magdeburg, GermanyPhysikalisch Technische Bundesanstalt, 38116 Braunschweig, GermanyBundesanstalt für Materialforschung, 12205 Berlin, GermanyWhile developing a standard for the determination of safety characteristics for hybrid mixtures the authors discovered, that, beside the ignition source, the mixing procedure is the main difference between the single-phase standards for dusts and gases. The preparation of hybrid mixtures containing a flammable gas and a flammable dust in the 20 L-sphere can be realized in different ways. Either the flammable gas is filled only in the sphere or only in the dust container or in both. In previous works, almost always the first method is applied, without giving any information on the accuracy of the gas mixtures. In this work the accuracy of the gas mixtures and the results of the tests applying two methods of mixing were studied. No significant influence of the mixing method itself on the safety characteristics explosion pressure p<sub>ex</sub> and the normalized rate of pressure rise (K-value) was found. Obviously, homogenization of the gas mixtures can be obtained sufficiently by the turbulence that is caused during the injection from the dust container into the explosion chamber within a short time. However, the mixing procedure has a great influence on the accuracy of the gas amount of the mixtures obtained. Without modifying the 20 L-sphere by installing precise pressure sensors, assuring its tightness and performing gas analysis, it must be expected, that the accuracy of the gas mixtures is very low. This has a significant influence on the measured safety characteristics and may lead to unsafe facilities or unnecessary expensive safety measures.https://www.mdpi.com/2571-6255/5/4/113hybrid mixtures20 L-spherepre-ignition pressure risepost-injection pressure dropsafety characteristicsmixing procedure |
| spellingShingle | Stefan H. Spitzer Enis Askar Kristin J. Hecht Dieter Gabel Sabine Zakel Arne Krietsch Requirements for a Hybrid Dust-Gas-Standard: Influence of the Mixing Procedure on Safety Characteristics of Hybrid Mixtures Fire hybrid mixtures 20 L-sphere pre-ignition pressure rise post-injection pressure drop safety characteristics mixing procedure |
| title | Requirements for a Hybrid Dust-Gas-Standard: Influence of the Mixing Procedure on Safety Characteristics of Hybrid Mixtures |
| title_full | Requirements for a Hybrid Dust-Gas-Standard: Influence of the Mixing Procedure on Safety Characteristics of Hybrid Mixtures |
| title_fullStr | Requirements for a Hybrid Dust-Gas-Standard: Influence of the Mixing Procedure on Safety Characteristics of Hybrid Mixtures |
| title_full_unstemmed | Requirements for a Hybrid Dust-Gas-Standard: Influence of the Mixing Procedure on Safety Characteristics of Hybrid Mixtures |
| title_short | Requirements for a Hybrid Dust-Gas-Standard: Influence of the Mixing Procedure on Safety Characteristics of Hybrid Mixtures |
| title_sort | requirements for a hybrid dust gas standard influence of the mixing procedure on safety characteristics of hybrid mixtures |
| topic | hybrid mixtures 20 L-sphere pre-ignition pressure rise post-injection pressure drop safety characteristics mixing procedure |
| url | https://www.mdpi.com/2571-6255/5/4/113 |
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