Thermal Radiation Intensity Research Articles

Improving the approach to assessing and rationing the effects of heat flow in a fire on the human body

The purpose of this study is to improve the method of assessing the risk of damage from exposure to heat flow in accidents with the combustion of hydrocarbons. Modern methods of calculating fire risk values used in Russia are largely based on methods developed by foreign colleagues. However, there are a number of points that are not taken into account in any guide. In the course of the study, it is advisable to conduct an experiment, the results of which will determine the dependence of the degree of damage to living tissues on the intensity and time of exposure to radiation. This dependence is the basis for a mathematical model of human damage by waves of any spectrum, including radiation during the combustion of hydrocarbons. The results of mathematical modeling will be the basis for the development of an approach to the assessment of individual fire risk indicators, the normalization of human thermal injury with varying exposure duration and intensity of thermal radiation.

HIGH-TEMPERATURE PROCESSES IN POWDER MATERIALS AT HIGH-VOLTAGE ELECTRIC PULSE CONSOLIDATION

The main features of high-voltage electric pulse consolidation (HVC) of refractory powder materials and the resulting unique capabilities of the method are considered. The electro-thermal processes of HVC at the contacts between powder particles and at the macroscale of the entire consolidated sample are analyzed. The results of experimental studies of the parameters of high-voltage electrical impulse action in the processes of consolidation of high-temperature powder compositions, high-voltage welding of dissimilar materials, as well as high-voltage discharges in liquid are presented. The results of measuring the intensity of thermal radiation of the investigated materials under high-voltage electrical impulse action, recorded by the method of pulse photometry using photodiode sensors, which, together with the Rogowski coil, are components of the measuring complex developed by the authors, are presented.

Asphalt pavement crack detection based on infrared thermography and deep learning

ABSTRACT The current intelligent detection of asphalt pavement cracks relies on visible images, which are ineffective in handling temporary shadow and reflection. In contrast, infrared images reflect thermal radiation intensity, making them suitable for crack detection by mitigating environmental interference. The GSkYOLOv5 method is proposed in this study for accurate crack detection in infrared images of asphalt pavement. Firstly, an infrared dataset consisting of 2400 images of asphalt pavement cracks was captured and produced, including three types of cracks – strip cracks, cross cracks and reticular cracks. And the imbalanced samples were balanced using generative adversarial networks. Secondly, GhostNet and Selective Kernel Networks were added to enhance crack information perception, and the SPPF module was replaced to improve feature learning for different scale cracks. Lastly, GSkYOLOv5 was tested with a self-built infrared dataset of asphalt pavement cracks. GSkYOLOv5 improved detection accuracy by 4.7% and recall rate by 1.3% compared to YOLOv5s, outperforming the other tested algorithms. This method can be combined with visible image-based crack detection for comprehensive intelligent detection of asphalt pavement cracks using dual lenses for visible and infrared images.

Study on the effect of forced convection and thermal radiation on foam stability

High expansion foam is widely used to mitigate cryogenic LNG spills, which is a major type of process safety accident. The stability of the foam affects the performance of hazard mitigation after cryogenic LNG spills. Forced convection and thermal radiation are key external factors affecting the foam stability, which depends on the foam drainage and breakage rates. The goal of this paper is to research the stability of high expansion foam under convection intensity of 0∼6 m/s and thermal radiation intensity of 0∼420 W/m2 following the actual environmental conditions through experiments and establish correlation models for predicting foam drainage rate and breakage rate based on the experimental results. The results show that increasing forced convection and thermal radiation will accelerate foam breaking, with forced convection having a greater effect, shortening the time of effective prevention in high expansion foam. The results of this work will guide high expansion foam mitigating LNG leakage accidents in complex environmental conditions.

Fire hazard and risk analysis of large fuel storage tank in IOC terminal

Fires and explosions in large oil storage tanks terminal cause significant loss of property and casualties and are always the concern of the world. To have proper understanding and knowledge about tank fires in terminals a detail study has been done considering various factors like safe separation distance, thermal radiation intensity and deluge water requirement. This paper offers the study of fire hazard especially the radiative heat flux absorbed by adjoining storage tanks. Large storage tanks fire has significant amount of energy release and causes strong thermal radiation to the properties and structures nearby. The thermal radiation intensity has been determined by providing safe separation distance recommended by various standards along with its permissible thermal radiation level for adjoining tanks. The calculated amount of mass flow rate of water required ranges in between 0.09 and 0.23 l/m2s which significantly varies from the recommendations of different code. However, by not ensuring required amount of water as a protective measure to safeguard the target tanks will put its integrity in doubt.

Analysis of the Relationship between APS Thermal Spray Parameters of Ni5Al Particles and Coating Characteristics

The strength and characteristics of a coating are defined by the impact and temperature of the individual molten particles, as well as by the state of the surface to be coated. The parameters selected for thermal spraying determine the parameters of the particles in flight: temperature and velocity. These parameters can be determined by measuring the thermal radiation intensity of the particles in flight. The parameters that define the thermal spray are the mass flow rate, the intensity, and the H2 flow rate in the gas mixture to be propelled into the spray gun. On the other hand, the strength of the coating obtained can be estimated using its hardness and adhesion. In this study, a design of the experiments is developed to determine the relationships between the operating parameters and the parameters characterising the particles. From this design, the results obtained are analysed. The experimental results confirmed the direct relationship between intensity and particle temperature, consistent with the relationship between intensity and energy generated in the arc in the spray device. The velocities followed a similar relationship. Increasing the proportion of H2 in the feed gas led to a higher heat transfer to the particles, consistent with the information found in the literature. A similar effect was detected for the velocity. The adhesion and hardness increase with the speed and temperature of the particle in flight, which is related to a more efficient spatter-flattening process. The applied procedure provides an efficient methodology for the development of useful surfaces for the optimisation of thermal spraying processes.

Investigation of stress-strain state of coil of tubular furnace radiant chamber at different arrangement of intermediate support

The coils of radiant chambers of tubular furnaces are operated under especially loaded conditions in terms of temperature stress distribution. It is in the radiant sections that the feed is heated to the required maximum temperatures. Also, part of the coil structure may be in close proximity to the burners and exposed to an open flame to form superheating zones. In this regard, the elements of the coil can deform and prematurely collapse. One of the most important roles is played by the support elements of the coil in the form of suspensions, brackets, etc., which serve to prevent sagging of the coil pipes. An important role is played by the optimal location of the support elements of the coils during design in order to prevent pipe sagging during operation. In the era of rapidly developing digital technologies, the problem of optimal location of support elements at the coil, taking into account the peculiarities of the design, operating parameters, and the intensity of thermal radiation, can help solve specialized software complexes. Special programs develop a coil model taking into account all the necessary parameters and characteristics, both material and technological process. This makes it possible to detect zones of concentration of increased stresses and maximum deformations. Therefore, the actual work is the modeling of the stress-strain coil of the radiant coil, taking into account the different locations of the support elements.

Study on the Influence of Offshore Elevated Flare on the Layout of LNG Terminal

In order to save land, the elevated flare of the LNG terminal is usually considered to be arranged on the sea. The thermal radiation and leakage evaporation diffusion of elevated flare are the key issues to be considered in the plane layout of the wharf. In this paper, the physical process of the flare thermal radiation and the evaporation and diffusion of the terminal sump are analyzed by using engineering knowledge. Combined with the theory of thermal radiation and vapor diffusion and the actual project scenario, the corresponding mathematical model is given and applied to the engineering practice for a large number of calculations. The following conclusions are drawn: (1) The thermal radiation received by the LNG terminal is weakly related to the flare height, that is, the effect of increasing the flare height to control the thermal radiation at the header is not obvious; There is a linear positive correlation with the flare treatment capacity; It is strongly inversely proportional to the distance from the wharf to the flare. It is preferred to reduce the thermal radiation intensity at the wharf by adjusting the distance between the wharf and the flare. When the distance between the wharf and the flare is greater than 100m, the thermal radiation value of the wharf is always less than the specified limit. (2) Within the scope of conventional design, the safe distance between the wharf working platform and the flare is about 20∼90m; The optimal safe distance between the wharf fire control room, bridge approach pipe gallery and the flare should be greater than 61m and 41m respectively. (3) The combustible vapor concentration at the flare is linearly and positively correlated with the flare height, so the flare height should be reduced as much as possible during design. (4) The combustible vapor concentration at the flare is negatively correlated with the distance from the flare to the terminal sump. It is found that the distance should not be less than 180m through calculation. When the distance is more than 300m, the combustible vapor concentration at the flare has little relationship with the flare height and the ambient wind speed. When the distance is more than 340m, the combustible vapor concentration at the flare is always less than the specified limit.

A study of the workers’ working conditions in areas of the manufacture castings from copper alloys

The results of the study of workers working conditions at the areas of the manufacture of castings from copper alloys are presented. It is noted that the main production factors of working conditions are noise, vibration, dustiness, gas contamination, temperature, intensity of infrared (thermal) radiation, severity and labor process intensity. The results have shown that at all workplaces there are exceedances of permissible values for noise and local vibration, the content of dust and harmful substances in the air of the working environment, the intensity of infrared (thermal) radiation and temperature. It is noted that the work performed due to the severity and labor process intensity can negatively affect the workers’ health.

Assessment of burner structure for methane-oxygen inverse diffusion flame based on laser detection: Reaction characteristics and soot analysis

The structure of a burner is a key issue of boilers and gasifiers in several industries. It significantly influences the flame formation and combustion reaction determining the mixing degree of fuel and oxidant. This study aims to explore the characteristics of flames at different angles and evaluate their advantages in specific applications. The present work explores the correlation between laser-induced breakdown threshold energy and flame temperature based on laser-induced breakdown spectroscopy (LIBS). Subsequently, the local structure and reaction characteristics of the flame at different burner angles (45, 60 and 90°) were investigated with simulation. The local equivalence ratio of the laminar flame was used to determine the distribution of reactants and components in the flame. The results indicated that the breakdown threshold energy was positively correlated with the temperature of the flame, and it was dependent on the gas concentration. With increased laser energy, the O/H ratio could be used as a function of the local equivalence ratio of the flame. In addition, the study of flame images and the spontaneous radiation of soot revealed that the C/H ratio in the flame reached the maximum value when the burner incident angle was 45°. Through simulation and experimental research, we found that the flame at 60° angle is the most stable, produces the least soot, has the highest combustion efficiency, and has better thermal radiation intensity.

Thermal stability of highly stable foams stabilized by nanoparticles and surfactants

Foams stabilized by nanoparticles (NPs) and surfactants have a great research potential in the development of environment-friendly firefighting foams. In the present study, foam dispersions, consisting of hydrophilic SiO2 NPs, a hydrocarbon surfactant (CAD-40), and a fluorocarbon surfactant (FS-50), were prepared to investigate the effect of NPs on the thermal stability of firefighting foams. The interactions between NPs and surfactants and foaming ability of the mixed dispersions were investigated. Foam decay, drainage, and coarsening under different thermal radiation intensities were systematically investigated. Results indicated that as the NP concentration was increased, the viscosity of the foam dispersions increased rapidly, the conductivity and foaming ability decreased, and the surface activity decreased initially and then increased. Foam volume decay, drainage, and coarsening under different temperatures were delayed by the NPs. As the concentration of NPs increased, the effect became more obvious. This study could provide theoretical guidance for the application of NPs in firefighting foams.

Numerical investigation of the entropy generation analysis for radiative MHD power-law fluid flow of blood through a curved artery with Hall effect

In the last few decades, mortality rate due to blood vessel diseases has hiked rapidly and it is almost one-third of total mortalities. Identifying the vascular geometry and hemodynamic blood flow inside the artery is essential for preventing vascular disease progression. By motivating vascular diseases effects on the human body, a mathematical model has been developed to discuss the blood flow phenomena and entropy estimation in the stenosed curved artery in the presence of a magnetic field and the Hall effect. The patient-specific condition of elliptic shape stenosis has been considered at the arterial wall. Blood is considered in the artery as two-phases; core and plasma region. Power-law fluid has been considered for core region fluid, while, Newtonian fluid is considered in the plasma region. The non-dimensional governing equations have been discretized using the second-order central difference method. Then, Stone's strongly implicit scheme is used in the ‘MATLAB’ software to solve a system of nonlinear partial differential equations (PDEs). A computing error tolerance of has been set for each iteration step throughout the computing process. The influence of various parameters such Hall parameter (m), Brinkman number (Br), flow behavior index (q), Radiation parameter (N), magnetic field (M), arterial curvature, etc., have been discussed graphically. The present study concludes that the heat transfer rate enhances with the increase in the Hall parameter values while wall shear stress reduces with it. In addition, the chances of stenosis deposition rise for highly curvature arteries, and also blood produces more entropy with the increase in viscous heating and thermal radiation intensity. Results from the current computational study will aid clinical researchers in making more accurate predictions about the prevalence of vascular diseases.

Ultra-Broadband Solar Absorber and High-Efficiency Thermal Emitter from UV to Mid-Infrared Spectrum.

Solar energy is currently a very popular energy source because it is both clean and renewable. As a result, one of the main areas of research now is the investigation of solar absorbers with broad spectrum and high absorption efficiency. In this study, we create an absorber by superimposing three periodic Ti-Al2O3-Ti discs on a W-Ti-Al2O3 composite film structure. We evaluated the incident angle, structural components, and electromagnetic field distribution using the finite difference in time domain (FDTD) method in order to investigate the physical process by which the model achieves broadband absorption. We find that distinct wavelengths of tuned or resonant absorption may be produced by the Ti disk array and Al2O3 through near-field coupling, cavity-mode coupling, and plasmon resonance, all of which can effectively widen the absorption bandwidth. The findings indicate that the solar absorber's average absorption efficiency can range from 95.8% to 96% over the entire band range of 200 to 3100 nm, with the absorption bandwidth of 2811 nm (244-3055 nm) having the highest absorption rate. Additionally, the absorber only contains tungsten (W), titanium (Ti), and alumina (Al2O3), three materials with high melting points, which offers a strong assurance for the absorber's thermal stability. It also has a very high thermal radiation intensity, reaching a high radiation efficiency of 94.4% at 1000 K, and a weighted average absorption efficiency of 98.3% at AM1.5. Additionally, the incidence angle insensitivity of our suggested solar absorber is good (0-60°) and polarization independence is good (0-90°). These benefits enable a wide range of solar thermal photovoltaic applications for our absorber and offer numerous design options for the ideal absorber.

Evaluating Urban Outdoor Thermal Comfort in Jabal Al Natheef Amman

Outdoor thermal comfort is an essential aspect of sustainable architecture, and it is key to maintaining a safe outdoor environment. Several programs have been developed to predict thermal comfort based on climate parameters, as well as the built environment, and to forecast comfort within the urban context. Solar radiation and wind speed can be manipulated by the constructed environment. This research uses Jabal Al Natheef as a case study. An attempt is made to evaluate the outdoor thermal comfort of the urban environment and to identify the contributing factors that impede or facilitate outdoor thermal comfort in Amman. The goal of this research is to investigate behavioral factors, including perception, in addition to environmental parameters, such as thermal adaptation and solar radiation intensity, as well as the green infrastructure implementation. A comprehensive literature analysis of outdoor thermal comfort over the last decade is conducted in this paper, which included adaptive and rational thermal comfort approaches, from the standpoint of contextualizing the behavioral perspective that is connected to the use of urban space. This research employed a scenario-based approach, enabling site assessment and community participation. The possibility of enhancing the outdoor thermal comfort in Jabal Al Natheef is discussed. Furthermore, we identify the effect of design measures that influence outdoor thermal comfort. Recommendations for improving outdoor thermal conditions in the region to improve urban life and stimulate outdoor activities are provided. The results indicate that vegetation has a significant effect on reducing air temperature by providing shade. Urban areas with more vegetation have a mean radiant temperature that is significantly reduced, by almost 7 °C, especially during the summer.

Evaluation of the safe separation distances of hydrogen-blended natural gas pipelines in a jet fire scenario

The desire for sustainable development in various countries has increased the use of hydrogen energy. Considering cost and time savings, the introduction of hydrogen into existing natural gas pipelines is an excellent option, and the failure consequences of hydrogen blending in natural gas pipelines should be considered. In this study, a solid flame model is used to calculate the thermal radiation intensity of a hydrogen-blended natural gas jet fire. A method is proposed to modify the calculation of the view factor in the near field, and parameters such as the specific heat capacity and calorific value of pure gas are replaced by the parameters of the mixed gas. The data of the Thornton and modified models are compared with the experimental results, and the modified model result is found to be more accurate. Using the modified model, the variations in different hydrogen blending ratios, internal pressures, and pipe diameters with the safe separation distance of the thermal radiation intensity in a pipeline accident are investigated, and the relationships between them are analyzed.

Modeling the risk of acetone emission from a storage tank in summer and winter

AbstractThe leakage of acetone from damaged tanks can threaten workers, surrounding facilities, and the environment. The safe storage of acetone is of vital importance for emergency planning and response. This paper focused on the effects and consequences of acetone leaks from a 200 m3 storage tank in the summer and winter seasons by the employment of Areal Locations of Hazardous Atmospheres. The hazard zones classified as red threat zone, orange threat zone, and yellow threat zone were determined and analyzed. Results showed that the risk distribution of the toxic acetone vapor cloud in summer was greater than those in winter. The summer and winter seasons have no significant effect on the thermal radiation intensities from pool fire and the Boiling Liquid Expanding Vapor Explosion (BLEVE) scenario. The maximum distance of toxicity, flammability, and thermal radiation from the pool fire and BLEVE scenario for the acetone leakage were 547, 111, 16, and 1100 m, respectively. The results would provide guidance for decision‐makers in safety management and emergency response to reduce hazards.

Investigation of the surface temperature in contact with plasma by two-color pyrometry

A high-speed two-color pyrometer has been developed that allows measuring the intensity of thermal radiation in temperature range of 100-3500oC with 2 μs time resolution. The analysis of the main factors affecting the measurement of surface temperature in the conditions of its interaction with plasma is carried out. It is shown that at plasma temperature of more than 10 eV and moderate concentration of particles, the wall plasma can be considered transparent to thermal radiation. Experimental studies on non-contact measurement of temperature of surface interacting with plasma on Globus-M2 tokamak and plasma gun test bench have been carried out. Sawtooth temperature fluctuations were detected on the wall of tokamak chamber near the exit of outer separatrix branch. The period of these flashes was 3-4 ms, and duration was 2 ms. The maximum wall temperature measured by a high-speed pyrometer exceeded the temperature measured by infrared camera. Measurements of temperature of the front surface of W-Li sample were carried out at plasma gun test bench under conditions of deuterium plasma jet cyclic action under loads simulating regimes of plasma current disruption in tokamak. The sample temperature reached more than 3000^oC during <1 ms. The thermal conductivity of the sample degraded with an increase in number of plasma exposure cycles, which was expressed in progressive decrease in target cooling rate after the pulse. Using a high-speed pyrometer, it is proposed to control the formation of heat-insulating foils on surface interacting with plasma Keywords: two-color pyrometer, thermal radiation, surface temperature, materials irradiation.

Исследование температуры поверхности, контактирующей с плазмой, методом двухцветной пирометрии

A high-speed two-color pyrometer has been developed that allows measuring the intensity of thermal radiation in temperature range of 100-3500 0C with 2 µs time resolution. The analysis of the main factors affecting the measurement of surface temperature in the conditions of its interaction with plasma is carried out. It is shown that at plasma temperature of more than 10 eV and moderate concentration of particles, the wall plasma can be considered transparent to thermal radiation. Experimental studies on non-contact measurement of temperature of surface interacting with plasma on Globus-M2 tokamak and plasma gun test bench have been carried out. Sawtooth temperature fluctuations were detected on the wall of tokamak chamber near the exit of outer separatrix branch. The period of these flashes was 3-4 ms, and duration was 2 ms. The maximum wall temperature measured by a high-speed pyrometer exceeded the temperature measured by infrared camera. Measurements of temperature of the front surface of W-Li sample were carried out at plasma gun test bench under conditions of deuterium plasma jet cyclic action under loads simulating regimes of plasma current disruption in tokamak. The sample temperature reached more than 3000 0C during < 1 ms. The thermal conductivity of the sample degraded with an increase in number of plasma exposure cycles, which was expressed in progressive decrease in target cooling rate after the pulse. Using a high-speed pyrometer, it is proposed to control the formation of heat-insulating foils on surface interacting with plasma.

A dynamic individual risk management method considering spatial and temporal synergistic effect of toxic substance leakage and fire accidents

Actual chemical industrial park accidents usually involve multi-hazard accidents. Synergistic effect of accidents could lead to serious casualties. In order to reduce the individual risk of accidents, this work proposes a method for managing the dynamic individual risk when toxic substance leakage and fire accidents occur concurrently, in which spatial and temporal synergistic effect of above two accidents is considered. The synergistic effect may reduce individual escape ability, and is modeled by quantifying the relationship between escape ability and toxic substance dose. In addition, the method analyzes dynamic individual risk of a person receiving the thermal radiation dose and toxic substance dose when escaping along a certain route. The casualty degree is described by the injury degree based on dose thresholds and the total fatality probability based on Probit model. Combined with the accident scenario, the critical safety escape distance is obtained. The model is proposed to plan the individual escape route based on the risk assessment results. The critical values of toxic substance concentration and thermal radiation intensity are defined as the basis for planning alternative escape routes. Finally, the optimal escape route is obtained according to the total fatality probability of each route. The range of safe escape direction can be used when wind direction information is inaccurate. A case study demonstrates the effectiveness of the proposed method and risk management strategy.

Modeling of the process of heating of chip‑powder dispersions of ferrous metals in the pass‑through muffle furnace of hot briquetting. Message 2

The simulation of the chip heating process in the zones of gas-flame and induction heating of a continuous muffle furnace has been carried out. The mechanisms of heat transfer (conductive, convective, radiative) that have a conjugated character are considered in the approximation of interpenetrating continuums in the absence of any noticeable influence of filtration processes under conditions of a highly porous chip medium. As a result of the analysis of heat and mass transfer in the porous chip body and the working space of the furnace, a system of equations was obtained for calculating temperature and concentration fields and fields of thermal radiation intensity depending on the specified furnace productivity, natural gas consumption, and oil concentration in the coolant. The system of equations, which is a model of heat and mass transfer processes, is closed and allows us to solve the problem posed – to determine the heating temperature of the chips at the exit from the gas-flame heating zone, the composition and residual content of the liquid phase in it, and also to find the optimal height and temperature of the inductor muffle in induction heating zone, dimensions and electrical parameters of the inductor.