Establishing regularities in the insulating capacity of a foaming agent for localizing flammable liquids

Likhnyovskyi²,

et al. 2023

An issue related to using cable products for building structures is to ensure their stability and durability when operating within wide limits. Therefore, the object of research was a change in the properties of the polymer sheath of the cable during the formation of a swollen coating layer under the influence of high temperature. It is proved that in the process of thermal action on the flame retardant coating, the process of thermal insulation of the cable involves the formation of particulate products on the surface of the sample. Under the action of the burner flame, a temperature was reached on the surface of the sample, which led to a swelling of the coating of more than 16 mm. The measured temperature on the inverse surface of the sample was no more than 160 °C, which indicates the formation of a barrier for temperature. In this regard, a calculation and experimental method for determining thermal conductivity when using a flame retardant as a coating has been developed, which makes it possible to estimate the coefficients of temperature conductivity and thermal conductivity under high-temperature action. According to the experimental data and established dependences, the coefficients of temperature conductivity and thermal conductivity of wood were calculated, which are 214.4·10–6 m2/s and 0.62 W/(m∙K), respectively, due to the formation of a heat-insulating swollen layer. The maximum possible temperature penetration through the thickness of the coating was assessed. A temperature was created on the surface of the sample, which significantly exceeds the ignition temperature of the polymer sheath of the cable, and, on a non-heated surface, does not exceed 160 °C. Thus, there is reason to argue about the possibility of directed adjustment of the fire protection processes of an electrical cable by using coatings capable of forming a protective layer on the surface of the material, which inhibits the rate of heat transfer.

Section: Discussion Of Results Of Studying the Process Of Formation O...mentioning

confidence: 58%

Determining the thermal-physical characteristics of a coke foam layer in the fire protection of cable articles with foaming coating

Likhnyovskyi²,

et al. 2023

“…This does not differ from practical data known from works [4, 5], the authors of which, by the way, also associate the effectiveness of heat loss reduction in heat supply systems with the formation of an effective thermal insulation layer. But, in contrast to the results of the studies reported in [23,24], the data obtained regarding the effect of the heat-insulating coating on the process of inhibiting the transfer of temperature allow us to state the following:…”

Section: Discussion Of Results Of Determining Thermal Conductivity An...mentioning

confidence: 59%

Determining thermal and physical characteristics of wood polymer material for pipeline thermal insulation

Tsapko,

Kasianchuk,

Likhnyovskyi

et al. 2023

One of the methods for ensuring the efficiency of pipelines for transporting heat-carriers during operation is their thermal insulation, which inhibits heat transfer processes and does not affect environmental indicators. Therefore, the object of research was wood, a polymer material made by polymerization of wood sawdust and dry mixtures of synthetic resins for thermal insulation of pipelines. It has been proven that in the process of thermal action on the heat insulating layer of wood polymer material, the process of heat inhibition involves the formation of pores. This is due to the fact that the thermal conductivity of the material depends on the volumetric mass, the decrease of which for a wood polymer product leads to a decrease in thermal conductivity. In this regard, the simulation of the process of heat transfer through a cylindrical heat-insulating layer made of wood of polymer material was carried out and the dependences derived, which allow obtaining a change in the dynamics of heat transfer and determining thermophysical properties. According to the experimental data and the established dependences, it was found that the thermal conductivity of the wood of the polymer material was within 2.4÷2.9·10-8 m2/s, the thermal conductivity of the sample did not exceed 0.030 W/(m∙K). In addition, the heat capacity of the product corresponds to a value of more than 1034÷1145 kJ/(kg·K) depending on the thickness, which accordingly categorizes it as a heat-insulating material. At the same time, data on thermal insulation properties for polyurethane foam show that when it is used with a density of 100 kg/m3, the thermal conductivity is 0.029 W/(m∙K), which is approximately the same as the value of the proposed wood polymer material. The practical value is the fact that the results of determining the heat-insulating properties of a wood polymer material make it possible to establish the scope and conditions of its application

“…Such conclusions can be considered appropriate from a practical point of view because they allow for a reasonable approach to the inhibition of the hydrocarbon flame by inorganic compounds when the isolation of oxygen of the hydrocarbon flame begins [14,15]. From a theoretical point of view, they allow us to assert the determination of the mechanism of the processes of both a decrease in the relative intensity of OH-radicals radiation and a change in the flame temperature, which are certain advantages of this study.…”

Section: Discussion Of Results Of Investigating the Process Of Flame ...mentioning

confidence: 99%

Identifying the regularities of n-heptane flame inhibition by inorganic compounds

Tsapko,

Likhnyovskyi

et al. 2024

The task related to using inorganic compounds for extinguishing flames is to enable their inhibitory capacity during operation within wide limits. Therefore, the object of the current research was aqueous solutions of inorganic salts, on which the effectiveness of inhibitory properties during interaction with n-heptane flame was established. It has been proven that increasing the mass flow rate of water by 1.5 mg/s reduces the intensity of OH-radicals radiation from 70 % to 30 % and lowers the flame temperature by 90 °C. However, it was found that when potassium salts are given, the intensity of OH-radicals radiation decreases by more than 6 times, potassium chloride and sulfate reduce the intensity of OH-radicals radiation by more than 2.8 times. Among ammonium salts, salts of dihydrogen phosphate and ammonium hydrogen phosphate reduce the relative intensity of radiation of OH radicals by more than 1.3 times. Sodium salts include nitrates and sodium chloride, which reduce the relative radiation intensity of OH radicals by more than 1.6 times. This is manifested, first of all, in the enrichment of the combustible environment with fuel. When determining the flame temperature of flammable liquids, it was established that n-heptane has the most stable and highest flame temperature, which is 1768 °C. When adding inorganic compounds to the flame of n-heptane, nitrate salt, and potassium chloride, the flame temperature increased by less than 20 °C. However, ammonium salts increased the flame temperature to over 140 °C, despite the presence of water. The practical significance is that the results were taken into account during the design and development of extinguishing agents for extinguishing fires. Therefore, there are reasons to assert the possibility of regulating flame extinguishing processes by using inorganic compounds capable of inhibiting active flame radicals