Future in Marine Fire-Fighting: High Pressure Water Mist Extinguisher with Abrasive Water Jet Cutting

Hlaváčová, Irena M.; Vondra, Adam

doi:10.17818/nm/2016/si5

Cited by 5 publications

(1 citation statement)

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“…Some basic relations between trends of the single-axis forces and the AWJ characteristics were presented in Reference [55]. Further investigation of the AWJ forces was focused on the mixing process [56], the AWJ diameter determination [57,58] or the recoil force of the hand tools [59].…”

Section: Introductionmentioning

confidence: 99%

Abrasive Waterjet (AWJ) Forces—Potential Indicators of Machining Quality

et al. 2021

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The necessity of monitoring the abrasive waterjet (AWJ) processes increases with the spreading of this tool into the machining processes. The forces produced on the workpiece during the abrasive waterjet machining can yield some valuable information. Therefore, a special waterjet-force measuring device designed and produced in the past has been used for the presented research. It was tested during the AWJ cutting processes, because they are the most common and the best described up-to-date AWJ applications. Deep studies of both the cutting process and the respective force signals led to the decision that the most appropriate indication factor is the tangential-to-normal force ratio (TNR). Three theorems concerning the TNR were formulated and investigated. The first theorem states that the TNR strongly depends on the actual-to-limit traverse speed ratio. The second theorem claims that the TNR relates to the cutting-to-deformation wear ratio inside the kerf. The third theorem states that the TNR value changes when the cutting head and the respective jet axis are tilted so that a part of the jet velocity vector projects into the traverse speed direction. It is assumed that the cutting-to-deformation wear ratio increases in a certain range of tilting angles of the cutting head. This theorem is supported by measured data and can be utilized in practice for the development of a new method for the monitoring of the abrasive waterjet cutting operations. Comparing the tilted and the non-tilted jet, we detected the increase of the TNR average value from 1.28 ± 0.16 (determined for the declination angle 20° and the respective tilting angle 10°) up to 2.02 ± 0.25 (for the declination angle 30° and the respective tilting angle of 15°). This finding supports the previously predicted and published assumptions that the tilting of the cutting head enables an increase of the cutting wear mode inside the forming kerf, making the process more efficient.

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Section: Introductionmentioning

confidence: 99%

Abrasive Waterjet (AWJ) Forces—Potential Indicators of Machining Quality

et al. 2021

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Upotreba niskodimnih bezhalogenih kabela u dizajnu protupožarne zaštite na brodu

Torrens¹,

Castells²

2018

Naše more

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Safety of shipping is a growing concern. The causes of shipping casualties are various. A fire on a ship is one of the most hazardous incidents which can happen on board and a common cause of damages and accidents in ships. However, this knowledge decreases where electrical installations, whose effects are not well-understood, are involved. Because of these effects and risks, the regulations related to cables for a vessel's electrical installations anticipate the use of special low fire propagation and fire-resistant cables made with low smoke emission and halogen-free materials. Despite these criteria, the regulations permit the use of materials such as PVC. The main purpose of this research is to identify the risks associated of the use of PVC versus Low Smoke Zero Halogen (LSOH) cables that could be present for equipment safety and people in case of fire. As a result of the implementation of the regulatory framework, test results carried out at UPC (Universitat Politècnica de Catalunya) Material testing lab from PVC and LSOH cables used in ships have been obtained. Finally, the use of LSOH cables is implemented to assess the effect of fire risk reduction measure for the enhancement of safety of shipping in coastal waters, efficiency and protection of the environment. Sažetak Sve više pozornosti posvećuje se sigurnosti u pomorstvu. Uzroci pomorskih nesreća mogu biti razni. Požar na brodu jedna je od najopasnijih pojava i čest uzrok šteta i nesreća na brodovima. Međutim, malo je spoznaja o uzrocima požara koji uključuju električne instalacije, te bi njihove posljedice trebalo bolje razumjeti. Zbog tih posljedica i rizika, propisi koji se odnose na kabele što se ugrađuju u brodske električne instalacije predviđaju uporabu specijalnih kabela koji sprečavaju širenje požara i otporni su na vatru, a napravljeni su od materijala koji ispuštaju niski dim i ne sadrže halogen. Unatoč tim kriterijima, propisi dopuštaju uporabu materijala poput PVC-a. Glavni je cilj ovoga istraživanja identificirati rizike povezane s uporabom PVC kabela u odnosu na niskodimne bezhalogene kabele (LSOH) koji bi se trebali stavljati radi sigurnosti opreme i ljudi u slučaju požara. Pridržavajući se važećih propisa, dobili smo rezultate testova provedenih na Politehničkom sveučilištu Katalonije (Universitat Politècnica de Catalunya) u laboratoriju za testiranje PVC i LSOH materijala koji se koriste na brodovima. Upotrebljeni su LSOH kabeli kako bi se utvrdili učinci mjera smanjenja rizika od požara radi bolje sigurnosti u pomorstvu u obalnim vodama, kao i učinkovitost i zaštita okoliša. KEY WORDS fire retardant and resistant cables safety LSOH material marine environment KLJUČNE RIJEČI kabeli za prigušivanje požara kabeli otporni na požar sigurnost LSOH materijal morski okoliš

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Kinematic characteristics of two-phase flows in waterjet cutting

Aleshkov

Volgina

2019

Vestnik MGSU

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1 Академия государственной противопожарной службы МЧС России (Академия ГПС МЧС России); г. Москва, Россия; 2 Национальный исследовательский Московский государственный строительный университет (НИУ МГСУ); г. Москва, Россия А ННОТА Ц И Я Введение. При гидроабразивной резке двухфазный поток, состоящий из воды и абразивных твердых частиц, двигается с высокой средней скоростью. Разрушение твердых материалов и сплавов обусловливает требование большой силы, а следовательно, сверх высокой скорости потока. Такие потоки сильно отличаются от природных и хорошо изученных потоков при гидротранспорте и гидрообработке. Определение кинематических характеристик при гидроабразивной резке представляет собой самостоятельную задачу. Материалы и методы. Представлены результаты полевых исследований определения основных базовых кинематических характеристик двухфазного потока. Условия транспортирования твердых частиц, эффективность их использования при резке, а также оценка энергетических потерь определены их физическими свойствами. Выявление особенностей двухфазных потоков, отличий от потоков воды -часть инженерных расчетов, направленных на эффективность их использования в различных сферах деятельности, в том числе и при пожаротушении. Результаты. Были проведены расчеты разнозернистости двухфазного потока, средневзвешенной плотности частиц, составляющих твердую фазу, расходной и действительной плотности потока. Приведены расчеты плотности двухфазного потока объемно-весовым способом и путем интегрирования распределения плотности твердых частиц по глубине. Выводы. Показано, что при гидроабразивной резке действительная плотность превышает расходную плотность на 8,5 %, что ниже значений, рекомендованных для гидротранспорта. Все инженерные расчеты необходимо вести с использованием значений действительной плотности потока. Полученные в настоящей работе кинематические характеристики являются основой для расчета дополнительных потерь напора на 1 м рукавной линии установки пожаротушения при транспортировке огнетушащих веществ. К ЛЮЧ ЕВЫЕ СЛО ВА: гидроабразивная резка, двухфазный поток, кинематические характеристики, разнозернистость, плотность двухфазного потока, абразив Д Л Я Ц ИТИРОВА НИ Я: Алешков М.В., Волгина Л.В. Кинематические характеристики двухфазных потоков при гидроабразивной резке // Вестник МГСУ. A B ST R ACTIntroduction. In waterjet cutting, a two-phase flow consisting of water and abrasive solid particles moves at a high average speed. Destruction of hard materials and alloys requires a large force and, therefore, a high flow rate. Such flows differ utterly from natural and well-studied flows in hydraulic transport and hydroprocessing. Determination of kinematic characteristics in the waterjet cutting is an independent task. Materials and methods. The results of field studies to determine the essential kinematic characteristics of the two-phase flow are presented. The conditions of transporting the solid particles, the efficiency of their application in cutting as well as the assessment of energy losses. The revelation of features...

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Future in Marine Fire-Fighting: High Pressure Water Mist Extinguisher with Abrasive Water Jet Cutting

Cited by 5 publications

References 6 publications

Abrasive Waterjet (AWJ) Forces—Potential Indicators of Machining Quality

Abrasive Waterjet (AWJ) Forces—Potential Indicators of Machining Quality

Upotreba niskodimnih bezhalogenih kabela u dizajnu protupožarne zaštite na brodu

Kinematic characteristics of two-phase flows in waterjet cutting

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