scholarly journals Fire risk of hull structures made of polymeric composites and ways to mitigate it

2021 ◽  
Vol 2 (396) ◽  
pp. 73-84
Author(s):  
S. Borodai ◽  
◽  
S. Kozlov ◽  
A. Letin ◽  
L. Rozum ◽  
...  
Keyword(s):  
Fire Protection ◽  
High Speed ◽  
Fire Hazard ◽  
Experimental Studies ◽  
Thermal Characteristics ◽  
Fire Risk ◽  
Practical Significance ◽  
Transfer Processes ◽  
Mass Transfer Processes ◽  
Under Construction

Object and purpose of research. The object of the study is polymer composite materials (PCM) used for manufac-turing hull structures of ships and vessels. The main purpose is to find the ways of fire protection of ships and vessels built from these materials. Materials and methods. The results of experimental studies and standard tests on the fire resistance of PCM structures, as well as methods of heat and mass transfer processes simulation in ship premises during fires, were used to determine the thermal characteristics affecting these structures. Main results. The ways of improving the fire safety of ships and vessels with PCM hull structures are determined. The list of problems to be solved in this area is outlined. Also this study has recommendations to improve the fire protection of the ships being designed, under construction and in operation. Conclusion. The structural PCM used in indigenous practice does not meet the current requirements of the International Maritime Organization (IMO) for Maritime Safety for fire protection of high-speed vessels and the requirements for fire protection of Navy ships. Ships that are in service and built using these materials do not provide additional measures to reduce their fire hazard. Fires on such ships can lead to disastrous consequences. It is necessary to solve this problem as soon as possible. The recommendations proposed in this paper on how to solve it, based on a large amount of experimental research, and they have great practical significance.

AFCEN RCC-F: A New Standard for the Fire Protection Design of New Built Light Water Nuclear Power Plants

2018 ◽  
Author(s):  
Bernard Gautier ◽  
Mickael Cesbron ◽  
Richard Tulinski
Keyword(s):  
Fire Protection ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Fire Hazard ◽  
Pressurized Water ◽  
Light Water ◽  
Protection Scheme ◽  
Safety Case ◽  
Under Construction

Fire hazard is an important issue for the safety of nuclear power plants: the main internal hazard in terms of frequency, and probably one the most significant with regards to the design costs. AFCEN is publishing in 2018 a new code for fire protection of new built PWR nuclear plants, so-called RCC-F. This code is an evolution of the former ETC-F code which has been applied to different EPR plants under construction (Flamanville 3 (FA3, France), Hinkley Point C (HPC, United Kingdom), Taïshan (TSN, China)). The RCC-F code presents significant enhancement and evolutions resulting from eight years of work by the AFCEN dedicated sub-committee, involving a panel of contributors from the nuclear field. It is now opened to any type of PWR (Pressurized Water Reactor) type of nuclear power plants and not any longer limited to EPR (European Pressurized Reactor) plants. It can potentially be adapted to other light water concepts. Its objective is to help engineers design the fire prevention and protection scheme, systems and equipment with regards to the safety case and the defense in depth taking into account the French and European experience in the field. It deals also with the national regulations, with two appendices dedicated to French and British regulations respectively. The presentation gives an overview of the code specifications and focuses on the significant improvements.

scholarly journals The influence of airflow on the effectiveness of rotary heat exchangers operating under high-speed rotor conditions

2019 ◽  
Vol 116 ◽  
pp. 00032
Author(s):  
Paulina Kanaś ◽  
Andrzej Jedlikowski ◽  
Sergey Anisimov ◽  
Borys Vager
Keyword(s):  
Mass Transfer ◽  
Heat Exchanger ◽  
Heat And Mass Transfer ◽  
Heat Exchangers ◽  
Heat Recovery ◽  
High Speed ◽  
Airflow Rate ◽  
Sharp Drop ◽  
Transfer Processes ◽  
Mass Transfer Processes

The paper presents an analysis of heat and mass transfer processes occurring inside the rotary heat exchanger operating under high-speed rotor conditions for different values of the airflow rate. For this purpose the original mathematical α-model was used. Conducted computer simulations allowed to determine the influence of Number of Transfer Units (NTU) of airflow on the temperature effectiveness as well as on the distribution of different active heat and mass transfer zones: “dry”, “wet” and “frost”. It was found that the increase of the values of NTU strictly affects the increase of the effectiveness of heat recovery. Another issue emerging from this study is the fact that in the certain range of low values of NTU there is no “dry” area created. It was established that at low values of NTU (NTU≈1) “frost” area extremum and sharp drop in the “frost” area accumulation are observed.

scholarly journals Tent fabric used by seasonal children’s camps: fire risk assessment

2021 ◽  
Vol 30 (1) ◽  
pp. 5-15
Author(s):  
N. I. Konstantinova ◽  
A. V. Zuban ◽  
E. A. Poedintsev ◽  
N. V. Golov
Keyword(s):  
Fire Safety ◽  
Fire Hazard ◽  
Experimental Studies ◽  
Fire Risk ◽  
Combustion Products ◽  
National Standard ◽  
Assessment Methodology ◽  
Safety Requirements ◽  
Technical Requirements ◽  
Materials Used

Introduction. The use of fireproof tent fabric at children’s tent camps remains a relevant problem. It may be resolved by developing a special flammability assessment methodology and criteria applicable to materials, used as the structural framework of tents. This solution will determine the choice of fabric.Aims and purposes. Materials, currently used to make tents, include natural or synthetic fabric and various polymers, that may be a fire hazard. In case of fire, safe evacuation of people may be unfeasible, although it is particularly important for children’s seasonal tent camps designated for sports and leisure.Domestic regulatory documents, that are currently in force, contain solely general technical requirements applicable to travel tents or ensuring fire safety in the territory of children’s tent camps, but there are neither fire safety requirements applicable to tent materials, nor any methods of their assessment. Meanwhile, there were cases of fire at children’s tent camps.The purpose of this work is to establish fire safety requirements applicable to tent materials used at children’s tent camps, to develop their testing criteria and methodology.The main objectives to be accomplished in order to achieve the pre-set purpose include the analysis of effective regulatory requirements and methods used to determine the flammability of tent materials, the establishment of parameters and criteria designated for their assessment and the development of a standard testing methodology.Results and discussion. Experimental studies were carried out to assess a set of flammability-related parameters of several types of fabric and polymers used to make outer/inner tents and ground sheets. It has been determined that currently used materials are fire-hazardous; therefore, it is advisable to limit the production of tents from combustible and flammable materials whose combustion may be triggered by low-calorie ignition sources, including those that can melt or release toxic combustion products.Currently used standard methods were applied to develop modified methodologies and classification criteria needed to assess the flammability of tent materials for children’s summer camps; experimental studies were also carried out.Conclusions. A draft national standard has been developed; it implies the establishment of the flammability assessment methodology and criteria and restricts the use of tent materials, that are extremely hazardous in terms of the toxicity of their combustion products.

scholarly journals Comparative analysis of variants of magnetic pole collection based on the halbach massif

2017 ◽  
Vol 3 (1) ◽  
pp. 47-57
Author(s):  
S A Kaznacheev ◽  
T S Zimenkova ◽  
A S Krasnov
Keyword(s):  
Comparative Analysis ◽  
High Speed ◽  
Permanent Magnets ◽  
Magnetic Levitation ◽  
Experimental Studies ◽  
Volume Growth ◽  
Practical Significance ◽  
Transport Systems ◽  
Cost Of Energy ◽  
Magnetic Poles

Today, one of the most urgent tasks of modern transport systems in terms of volume growth and quality improvement, freight and passenger transportation worldwide, is to increase the speed of transportation and reduce the cost of energy resources associated with these transportations. These tasks can be solved by introducing high-speed, in particular magnetic-lev- el transport systems. In this paper, we describe and compare the variants of assemblies of magnetic poles based on the Halbach massif. The relevance of the studies carried out is confirmed by the world experience in the use of permanent magnets in the field of magneto-levitation technologies in various branches of science and technology. The purpose of the research and comparative analysis of variants of assemblies of magnetic poles based on the Halbach massif is to obtain data on the possibility of using such assembly variants in levitation systems of magnetic-leav- ing transport [7], as well as visual proof that mathematical modeling does not allow to fully describe emerging phenomena In this article, we use empirical methods of investigation. The results obtained will find their application in the design of the design, which will reduce both the mass-dimensions and the energy consumption of the levitation system. The practical significance of the studies obtained lies in the possibility of applying the principles considered practically in any magnetic-levitation transport systems. Conclusion: Based on the experimental studies, data were obtained on the levitation forces and the braking forces, which make it possible to draw conclusions about the advisability of using these assembly variants.

The effect of fire protection means on the intensity of heating and features of charring of wooden structures

2021 ◽  
Vol 94 ◽  
pp. 50-64
Author(s):  
I. O. Fedotov ◽  
◽  
A. B. Sivenkov ◽  
Keyword(s):  
Flame Retardant ◽  
Fire Resistance ◽  
Fire Protection ◽  
Flame Retardants ◽  
Large Scale ◽  
Fire Hazard ◽  
Experimental Studies ◽  
Systematic Research ◽  
Muffle Furnace ◽  
Wooden Structures

Introduction. Over the past decades, the sphere of wooden house construction has been undergoing revolutionary changes in relation to the development of large-scale construction using wood-based structures. In this regard, one of the first places is the direction associated with ensuring the fire-safe use of such structures in the construction of buildings and structures of various functional purposes. An important sector of this direction is various types and methods of fire protection for wood, materials and structures based on it. The lack of systematic research on these issues hinders the development of effective technical solutions for fire protection of wooden structures. Goals and objectives. Identification of priority areas for research in the field of fire protection of wood, materials and structures based on it. Development of effective flame retardants that can have an impact on reducing fire danger and increasing the fire resistance of wooden structures. Determination of the influence of various flame retardants on the intensity of the process of heating and charring of elements of wooden structures in conditions of fire exposure (fire). Methods. A standard muffle furnace of the SNOL type was used as a test installation with the possibility of one-sided radiation thermal effect on the sample surface and a uniform temperature increase in the furnace up to 1200 С. The muffle furnace was upgraded taking into account the horizontal fixing of the sample on the outer panel of the furnace. To measure the temperature by the thickness of the sample, a set of thermoelectric converters of type K (chromel-kopel) with a junction diameter of 0,8 mm was used. Results and their discussion. Based on the results of theoretical and experimental studies, the main directions of research on the possibility of using various methods and types of fire protection to achieve the required fire hazard characteristics and fire resistance of wooden structures were determined. During the study, the analysis of such characteristics of charring as the rate of charring, the thickness of the charred layer was carried out. Conclusion. The research results show the possibility of certain classes of flame retardants, intumescent and heat-protective materials not only to influence the intensity of the process of charring wood, but also to affect the properties and structure of the charred layer, as well as the intensity of heating of the inner layers of wooden structures. Key words: fire resistance, fire resistance limit, fire hazard, charring, heating intensity, flame retardant efficiency, wood, wooden structures, flame retardant coatings, flame retardants.

scholarly journals ВПЛИВ ГІДРОДИНАМІЧНОЇ КАВІТАЦІЇ НА ЗМІНУ ТЕМПЕРАТУРНИХ ПОКАЗНИКІВ ВОДИ

2018 ◽  
Vol 82 (1) ◽  
Author(s):  
Леся Юріївна Авдєєва ◽  
Е. К. Жукотський ◽  
А. А. Макаренко
Keyword(s):  
Tap Water ◽  
Experimental Studies ◽  
Rate Of Change ◽  
Hydrodynamic Cavitation ◽  
Transfer Processes ◽  
Mass Transfer Processes ◽  
Total Temperature ◽  
Temperature Indices ◽  
Venturi Nozzle

В статті розглянуті питання, пов’язані із виникненням і розвитком явища гідродинамічної кавітації при обробці рідких середовищ. Показана актуальність і можливості практичного використання ефектів, що супроводжують гідродинамічну кавітацію, для інтенсифікації енергоємних процесів у різних галузях промисловості. Проаналізовано механізм інтенсифікуючого впливу дії ефектів кавітації в тепломасообмінних процесах. Описано переваги використання гідродинамічних кавітаторів статичногго типу на прикладі сопла Вентурі. Наведено результати експериментальних досліджень впливу ефектів гідродинамічної кавітації в соплі Вентурі на зміну температурних показників водопровідної води для визначення раціональних гідродинамічних умов проведення процесу обробки. Представлено дані, що характеризують зміни температурних показніків водопровідної води з різною початковою температурою в залежності від тривалості проведення процесу для сопел з різним діаметром горловини. Показано, що збільшення тривалості обробки посилює вплив кавітаційних ефектів на матеріал. Встановлено, що  зменшення діаметру горловини сопла призводить до підвищення температури зразка в результаті його обробки. Найбільші кавітаційні ефекти виникають при діаметрі горловини сопла Вентурі 0,008 м і 0,012 м. Встановлення діафрагми, що перекриває потік на 75% показало додаткове загальне підвищення температури на 3-6 °С, порівняно до отриманих результатів для зразка обробленого в кавітаційному змішувачі без діафрагми. Підвищення температури за рахунок встановлення діафрагми пояснюється посиленням дії кумулятивних ефектів внаслідок гідродинамічної кавітаційної обробки. Аналіз результатів експериментальних досліджень дозволив отримати математичну залежність числа кавітації від швидкості зміни температури за якою можна оцінити ефективність роботи кавітаційного змішувача.   The article deals with issues related to the emergence and development of the phenomenon of hydrodynamic cavitation in the processing of liquid media. The actuality and possibilities of practical use of the effects accompanying hydrodynamic cavitation for the intensification of energy-intensive processes in various industries are shown. The mechanism of intensifying influence of cavitation effects in heat and mass transfer processes is analyzed. The advantages of static type hydrodynamic cavitators using the Venturi nozzle example are described. The results of experimental studies of the influence of the effects of hydrodynamic cavitation in the Venturi nozzle on the change of the temperature indices of tap water for the determination of rational hydrodynamic conditions of the processing process are given. The data describing changes in temperature indices of tap water with different initial temperature are presented, depending on the duration of the process for nozzles with different diameter of the neck. It is shown that increasing the duration of processing enhances the effect of cavitation effects on the material. It was established that the decrease of the diameter of the nozzle's neck leads to an increase in the sample temperature as a result of its treatment. The largest cavitation effects arise at a diameter of the neck of the Venturi nozzle 0,008 m and 0,012 m. The installation of an aperture overlapping the flow by 75% showed an additional total temperature increase of 3-6 ° C, as compared to the results obtained for a sample treated in a cavitation mixer without a diaphragm. The increase in temperature due to the installation of the diaphragm is due to an increase in the effect of cumulative effects due to hydrodynamic cavitation treatment. The analysis of the results of experimental studies allowed to obtain mathematical dependence of the number of cavitation on the rate of change in temperature on which it is possible to estimate the efficiency of the cavitation mixer.

scholarly journals RESEARCH OF ADHESIVE AND HEAT-PROTECTIVE PROPERTIES OF RUBBERS BASED ON EPDM WITH ARAMID FILLER

2020 ◽  
pp. 53-61
Author(s):  
Galina Shaydurova ◽  
◽  
Dmitriy Oros ◽  
Natalya Povarnitsyna ◽  
◽  
...  
Keyword(s):  
Adhesive Strength ◽  
Thermophysical Properties ◽  
High Speed ◽  
Phenol Formaldehyde ◽  
Experimental Studies ◽  
Practical Significance ◽  
Laboratory Research ◽  
Formaldehyde Resin ◽  
Ethylene Propylene ◽  
Vulcanized Rubber

Reinforced materials of the "fabric filler-vulcanized rubber" type may be successfully operated under the condition of the specified adhesive strength at the interface of the "substrate-polymer (rubber) "contact. The article presents theoretical infor-mation about ethylene propylene (EDM) and ethylene-propylene-diene (EPDM) synthetic rubbers, known internationally under the brand name EPDM-monomer, arimide fiber and laboratory research methods. The advantages of using EDM and EPDM in the manufacture of heat-protection coatings are; high heat resistance, low density, good compatibility with fillers (mineral and synthetic), compatibility with epoxy and phenol-formaldehyde resins, belong to coking materials. The article also provides the results of experiments and analysis of the data obtained, namely, the adhesive strength and thermal effect of rubbers based on EPDM with an arimide filler of a non-woven structure. The object of the research was modified heat-protective materials based on EPDM, and the subject of the research was selected rubber compounds based on EPDM and synthetic arimide fiber. To as-sess the physicochemical and thermophysical properties, a derivatographic analysis was performed, which includes TGA and DTA, two vulcanized rubber-woven samples from rubbers of grades 51-1615, 51-2110 together with arimide fiber. For the first time, results were obtained using ethylene-propylene-diene rubbers, including modification with a phenol-formaldehyde resin, which gives a higher erosion resistance when exposed to high-speed heat flow. Analysis of the results of experimental studies has shown that the use of arimide fiber can provide higher strength and thermophysical properties of heat-protective materials. In general, the results obtained may be of practical significance for the development of new-generation products.

scholarly journals Multistage Shelf Devices with Fluidized Bed for Heat-Mass Transfer Processes: Experimental Studies and Practical Implementation

2021 ◽  
Vol 11 (3) ◽  
pp. 1159
Author(s):  
Mykola Yukhymenko ◽  
Artem Artyukhov ◽  
Ruslan Ostroha ◽  
Nadiia Artyukhova ◽  
Jan Krmela ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Fluidized Bed ◽  
Heat Mass Transfer ◽  
Structural Parameters ◽  
Experimental Studies ◽  
Shelf Space ◽  
Interphase Heat Transfer ◽  
Transfer Processes ◽  
Mass Transfer Processes

The article deals with the theoretical description and experimental study of the hydrodynamic and heat transfer properties regarding the operation of multistage gravitational devices of the fluidized bed with inclined perforated shelves. The peculiarities of the work and the implementation field of the multistage shelf units are described. A theoretical model to define the solubilizer’s velocity above the perforation holes, in the above-shelf space of the device and in the outloading gap, as well as the residence time of the dispersed phase at the stage (perforated shelf contact) of the device is presented. The results of experimental studies regarding the influence, made by the structural parameters of the perforated shelf contacts, on the distribution pattern of single-phase and gas-dispersed flows in the workspace of the device, on the intensity of interphase heat transfer are presented. The conditions to create active hydrodynamic operating modes of multistage gravitational shelf devices, which provide higher efficiency of heat-mass transfer processes, and with lower gas consumption and hydraulic resistance compared to typical fluidized bed devices, are proved. Peculiarities regarding the implementation of heat-mass transfer processes in multistage devices are described using heat treatment and drying processes as examples.

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