scholarly journals Теплофизические характеристики теплозащитного пакета корпуса ракетного двигателя при программированном нагреве

2021 ◽  
pp. 74-82
Author(s):  
Юрий Игоревич Евдокименко ◽  
Ирина Александровна Гусарова ◽  
Геннадий Александрович Фролов ◽  
Вячеслав Михайлович Кисель ◽  
Дмитрий Валериевич Боровик ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Specific Heat ◽  
Thermal Loading ◽  
Thermal Protection ◽  
Steel Substrate ◽  
Temperature Fields ◽  
Thermal Testing ◽  
Thermophysical Characteristics ◽  
Temperature Range ◽  
Temperature Dependences

An experimental determination of the temperature dependences of the thermophysical characteristics of the MFP-92 multifunctional coating in the operating temperature range under thermal loading, simulating standard flight conditions, has been carried out. Heating was carried out with a jet of an industrial oxygen-propane burner mounted on a tripod with the possibility of varying the distance to the surface of the sample. The programs of the material operating modes include two peaks of heating to a temperature of ~1400 ° C with a heating and cooling rate of 20 - 40 deg / s. Under such conditions, thermal degradation of the MFP-92 material occurs, which changes its phase composition, structure, and, accordingly, thermophysical characteristics (TPС). The main transformations in the MFP-92 material occur in the temperature range up to 1000 °C, therefore, the heat transfer in it for given heating programs can be described using a simplified TРС model. This model assumes the existence of material in two states - initial (phase A) and annealed with completely completed transformation processes (phase B), each of which is assigned its own set of TPC. To determine the TPC of the MFP-92 material in its samples during thermal testing, temperature fields were recorded, which were then processed using the method of solving the inverse (coefficient) problem of thermal conductivity on a computer model. As a result, the temperature dependences of the specific heat and the coefficient of thermal conductivity of phases A and B were obtained, as well as the value of the most powerful thermal effect of the phase transition at 110 °C in phase A. The remaining phase transitions were taken into account by the corresponding changes in the specific heat. During material testing, the emissive of the material is also determined. Verification of the two-phase model of the MFP-92 material and the obtained values of its TPC was carried out based on the temperature fields obtained during the thermal tests of the samples of the three-layer thermal protection package "MFP-92 material-thermal insulation-steel substrate" under heating conditions according to the operating mode program confirmed their adequacy.

Теплофизические характеристики теплозащитного материала корпуса ракетного двигателя при температурах до 1000 оС

2021 ◽  
pp. 11-18
Author(s):  
Геннадий Александрович Фролов ◽  
Юрий Игоревич Евдокименко ◽  
Вячеслав Михайлович Кисель ◽  
Ирина Александровна Гусарова
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Temperature Fields ◽  
Thermophysical Characteristics ◽  
Furnace Heating ◽  
Temperature Dependences ◽  
Good Agreement

An experimental determination of the temperature dependences of the specific heat capacity and the thermal conductivity coefficient of the multifunctional coating MFP-92 at temperatures up to 1000 °C has been carried out. At temperatures up to 450 °C, an IT-c-400 device was used to determine the specific heat capacity. IT-l-400 device was used for the determination of thermal conductivity. At higher temperatures, the determination of the thermophysical characteristics (TPC) was carried out by solving the inverse problem of thermal conductivity (IPT) in a flat plate under conditions of one-sided heating in a muffle furnace. Composite material MFP-92 is a multilayer structure with upper layers based on silica fabric and chromophosphate binder and lower layers based on mullite-silica fabric and aluminosilicate binder. The TPC of the layers also differ from each other, and, accordingly, the properties of this material as a whole can be determined only in the form of their effective values, averaged in one way or another over the thickness of the coating. In addition, during heating, the material undergoes significant physicochemical transformations associated with the thermal destruction of its components, manifested in the form of abundant gas release, and a decrease in the density of the material, which significantly changes its TPC and determines its dependence on the heating rate. Therefore, studies of the thermophysical characteristics of the MFP-92 material were carried out with several (2-5) consecutive heating cycles. It was found that in four heating cycles of the MFP-92 material up to 450 °C for 75 minutes when measuring the specific heat on the IT-c-400 device, its temperature dependence significantly changes qualitatively and quantitatively. With furnace heating to 1000 °C, the temperature dependences of the TPC of the material, determined in the first and second heating cycles, have a different form, but change insignificantly in subsequent heating cycles. This makes it possible to ascribe to the MFP-92 material a set of two sets of TPC related to its initial (phase A) and annealed after heating to 1000 °C (phase B) states. Using the obtained TPС of phase A (including the magnitude of the thermal effect of irreversible endothermic phase transition at 100 °C) and phase B, good agreement was obtained between the calculated and experimental temperature fields in the samples under furnace heating conditions.

EXAMINATION OF THERMOPHYSICAL CHARACTERISTICS OF A HEAT-PROTECTIVE MATERIAL BASED ON FIBERGLASS DURING DESTRUCTION

2021 ◽  
pp. 91-97
Author(s):  
D.Ya. Barinov ◽  
◽  
S.Yu. Shorstov ◽  
M.G. Razmahov ◽  
A.I. Gulyaev ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermophysical Properties ◽  
Thermal Effects ◽  
Space Technology ◽  
Muffle Furnace ◽  
Thermophysical Characteristics ◽  
Initial State ◽  
Protective Material ◽  
Temperature Dependences

When designing advanced samples of aviation and rocket and space technology, during the operation of which the temperature on the surface of the material can exceed the temperature of destruction, it is important to have an understanding of the values of thermophysical properties. The work investigates the thermophysical properties of fiberglass in the initial state and after the binder is burned out in a muffle furnace. The temperature dependences of thermal effects, heat capacity, thermal diffusivity and thermal conductivity were determined, density was measured, and thermogravimetric analysis was carried out. Using a stereomicroscope, the microstructure of the lateral cut of the samples was examined and its evolution was determined during the burning of the binder.

Thermophysical Properties of Pongama Honge Oil Methyl Ester and Rubber Seed Oil Methyl Ester for Wide Temperature Range

2019 ◽  
Vol 11 (4) ◽  
Author(s):  
Shaik Moulali ◽  
Y.V. Hanumantha Rao ◽  
Vinay Atgur ◽  
G. Manvendra ◽  
G.P. Desai
Keyword(s):  
Thermal Conductivity ◽  
Methyl Ester ◽  
Thermal Degradation ◽  
Specific Heat ◽  
Seed Oil ◽  
Edible Oils ◽  
Rubber Seed Oil ◽  
Rubber Seed ◽  
Temperature Range ◽  
Honge Oil Methyl Ester

Thermal energy is used in the process of heating, cooling and product design purpose. In this work, two non-edible oils are considered and their thermal conductivity, specific heat and thermal degradation are experimentally determined as a function of temperature using, guarded hot plate method, differential scanning calorimetry (DSC) and thermogravtic analyser (TGA). Miniature difference between the obtained and actual thermal conductivity values are influenced by the fatty acid composition. In the present work Pongamia Honge Oil Methyl Ester (HOME) and Rubber Seed Oil Methyl Ester (ROME) are studied and their properties are determined experimentally for a temperature range of 25 to 80C. It has been observed that thermal conductivity of HOME decreases from 0.168 to 0.124 W/mK and for ROME thermal conductivity decreases from 0.143 to 0.113 W/mK. Thermal degradation and specific heat were studied using TGA and DSC. Specific heat was studied in the range from 35 to 120 C. For HOME, the specific heat varies from 2.345 to 2.64 kJ/kgK. For ROME, the specific heat varies from 1.572 to 1.992 kJ/kgK.

scholarly journals Thermal Conducting Properties of Metal-fluoroplastic Material Determined by Tribological Method

2021 ◽  
pp. 378-384
Author(s):  
Vasily N. Kornopoltsev ◽  
Bair B. Damdinov
Keyword(s):  
Thermal Conductivity ◽  
Sheet Metal ◽  
Thermal Conductivity Coefficient ◽  
Steel Substrate ◽  
Approximate Determination ◽  
Fourier Law ◽  
Thermophysical Characteristics ◽  
Friction Zone ◽  
Thermal Conducting

The work is devoted to considering the possibility of using the Fourier law and the data of tribological tests for the approximate determination of the thermophysical characteristics of the sheet metal-fluoroplastic material on a steel substrate. The thermal conductivity coefficient of two different fluoroplastic materials was determined by tribological method using the temperature difference in the friction zone. It was shown that friction conditions change from viscoelastic to plastic

scholarly journals ТЕПЛОФИЗИЧЕСКИЕ ХАРАКТЕРИСТИКИ И ТЕРМОЭРОЗИОННАЯ СТОЙКОСТЬ КЕРАМИЧЕСКОГО МАТЕРИАЛА НА ОСНОВЕ КАРБИДА БОРА

2020 ◽  
pp. 136-145
Author(s):  
Юрий Игоревич Евдокименко ◽  
Ирина Александровна Гусарова ◽  
Геннадий Александрович Фролов ◽  
Вячеслав Михайлович Кисель ◽  
Сергей Васильевич Бучаков
Keyword(s):  
Thermal Conductivity ◽  
High Temperature ◽  
Heat Resistance ◽  
Specific Heat ◽  
Thermal Conductivity Coefficient ◽  
Erosion Resistance ◽  
Combustion Products ◽  
Structural Ceramics ◽  
Radiation Coefficient ◽  
Temperature Dependences

A study of the thermophysical characteristics, heat resistance, and thermal erosion resistance of high-temperature structural ceramics (SC), which was developed at NTUU "I. Sikorsky Kyiv Polytechnic Institute" under the supervision of Corresponding Member of the National Academy of Sciences of Ukraine, Professor P. I. Loboda was made. This high-temperature structural ceramics is intended for use in aerospace engineering, in particular - for the manufacture of aerodynamic surfaces of reusable hypersonic aircraft and heat-stressed elements of the gas-dynamic paths of their engines. The samples of B4C-SiC-B6Si ceramics of two compositions (No. 1 and No. 2) were studied, which differ in the mass content of the initial components. Temperature dependences of the specific heat and thermal conductivity of the spacecraft, radiation coefficient, heat resistance in an oxidizing environment, and the thermal erosion resistance in supersonic flow of combustion products of an air-kerosene fuel mixture were determined. The temperature dependence of the specific heat was determined using an IT-c-400 instrument (in the range of 40 °C - 440 °C) and by the calculation of the temperature dependences of the specific heat capacity of the system components following the Reno rule (up to 2100 °C). The temperature dependence of the thermal conductivity coefficient of the SC of composition No. 1 was determined by solving the inverse heat conduction problem on a computer model based on experimental data. Temperature fields and heat fluxes were obtained under conditions of one-sided heat-ing with a reducing flame of a propane-oxygen welding burner. The thermal conductivity coefficient of SC composition No. 1 increases from 11 W/(m×K) at 20 °С to 25 W/(m×K) at 1400 °С. Its radiation coefficient in the temperature range 1000 °С - 1400 °С is ε = 0.96 ± 0.02. Heat resistance of SC of both compositions in the oxidizing flame of an oxygen welding burner at a surface temperature of 1400 °C has demonstrated that after two hours of heating, the average values of mass ablation for the two tested samples of compositions №1 and № 2 respectively 2.1% and 1.4% (a sample thickness of 4 mm). Tests in the supersonic flow of combustion products at the same surface temperature confirm the high resistance of the material to thermoerosion in the oxidizing medium. The change in the morphology of the heated surface of the sample after six five-minute heating cycles was manifested only by an increase in its roughness without visible oxidation. High thermal conductivity, heat and thermoerosion resistance, radiation coefficient of the studied SC at a temperature of 1400 °C in combination with low density (2.7 g / cm3) make this high-temperature structural material of aerospace technology promising for use.

Thermophysical Properties of Germanium for Thermal Analysis of Growth from the Melt

1981 ◽  
Vol 9 ◽  
Author(s):  
Roger K. Crouch ◽  
A. L. Fripp ◽  
W. J. Debnam ◽  
R. E. Taylor ◽  
H. Groot
Keyword(s):  
Thermal Conductivity ◽  
Thermal Analysis ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Thermophysical Properties ◽  
Room Temperature ◽  
Bridgman Method ◽  
The Other ◽  
Temperature Range ◽  
Diffusivity Measurements

ABSTRACTThe thermal diffusivity of Ge has been measured over a temperature range from 300° C to 1010° C which includes values for the melt. Specific heat has been measured from room temperature to 727° C. Thermal conductivity has been calculated over the same temperature range as the diffusivity measurements. These data are reported along with the best values from the literature for the other parameters which are required to calculate the temperature and convective fields for the growth of germanium by the Bridgman method. These parameters include the specific heat, the viscosity, the emissivity, and the density as a function of temperature.

scholarly journals Влияние морфологических дефектов на теплофизические свойства gamma-Gd-=SUB=-2-=/SUB=-S-=SUB=-3-=/SUB=-

2018 ◽  
Vol 60 (3) ◽  
pp. 482
Author(s):  
А.В. Сотников ◽  
В.В. Баковец ◽  
А.Ш. Агажанов ◽  
С.В. Станкус ◽  
Д.П. Пищур ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Single Crystal ◽  
Temperature Range ◽  
Ceramic Samples ◽  
Temperature Dependences ◽  
Morphological Defects ◽  
Large Heat

AbstractThe temperature dependences of the heat capacity ( C _ p ) and the thermal conductivity (κ) in the temperature range from 300 to 773 K of polycrystalline gadolinium sulfide samples (γ-GdS_ y ) with the deviation of the composition from the integer stoichiometric were studied. It was found that the thermal conductivity of gadolinium sulfides decreases monotonically and reaches 0.74 W/(m K) at T = 773 K for the composition y = 1.479, which is much lower than for the known single-crystal samples. The influence of morphological defects (boundaries of crystallites and dislocations) on the intensity of scattering of phonons is studied. It has been established that ceramic samples of gadolinium sulphides have a large heat capacity and a lower thermal conductivity, in comparison with monocrystalline samples of the same composition.

scholarly journals Thermal state analysis of energy saving structures of cast-in-place lightweight aggregate concrete walls

2018 ◽  
Vol 143 ◽  
pp. 01002
Author(s):  
Nikolay Tsvetkov ◽  
Andrei Khutornoi ◽  
Alexandr Kozlobrodov ◽  
Anna Kolesnikova ◽  
Elena Ivanova ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Protection ◽  
Thermal State ◽  
Numerical Study ◽  
Lightweight Aggregate ◽  
Temperature Fields ◽  
Lightweight Aggregate Concrete ◽  
Geometrical Parameters ◽  
Software Complex ◽  
The Impact

The purpose of this paper is numerical study on the impact of location of cylindrical fillers made of insulating material on the thermal state and thermal protection properties of the corner fragment of cast-in-place lightweight aggregate external wall. Solution of spatial thermal conductivity problem was obtained and the effect of low-thermal-conductivity fillers location inside the corner fragment of a wall was analyzed using the software complex Ansys. The nature of temperature fields distribution was determined both inside the wall and in the inner corner of the structure. The method for temperature increase in the inner corner is suggested and its quantitative evaluation is performed. The effect of thermophysical and geometrical parameters of wall materials on its thermal insulation properties is analyzed.

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