Assessment of the Thermal Radiation Regime of the Crane Operator Workplace for Making the Reasonable Choice of the Climate System of the Metallurgical Crane Cabin

2021 ◽  
pp. 7-14
Author(s):  
B.Ch. Meskhi ◽  
◽  
Yu.I. Bulygin ◽  
V.V. Maslensky ◽  
I.N. Loskutnikova ◽  
...  
Keyword(s):  
Thermal Radiation ◽  
Gas Flow ◽  
Thermal Protection ◽  
Side Wall ◽  
Climate System ◽  
Design Stage ◽  
Front Wall ◽  
Thermal Irradiation ◽  
Radiation Regime ◽  
Reasonable Choice

The tendency of increasing of radiation sources power in metallurgy leads to an increase in the level of thermal radiation at the crane operator workplaces. The state of their health is characterized by a decrease in physical performance, the occurrence of colds, and occupational diseases of the cardiovascular and respiratory systems. Therefore, it is necessary to evaluate the thermal radiation regime of the crane operator workplace for further justification of the choice of the method and means of thermal protection. To assess the thermal irradiation of the metallurgical crane cabin, along with the method of building the thermal irradiation plot, the finite element method was used which was integrated into the automated software package ANSYS, into its plug-in Fluid Flow (Fluent) designed to build models of convective energy transfer by a liquid or gas flow. Flow turbulence is described by the Shear Stress Transport (SST) model. The article examines the thermal radiation situation in the steelmaking shop, which determines the choice of means to ensure an optimal microclimate at the crane operator workplace. It was revealed that the thermal radiation and the temperature of the railings of the metallurgical crane cabin significantly exceed the maximum permissible level, as a result of which it became impossible to choose a climate system that provides for a comfortable air temperature inside the cabin. To reduce the thermal load on the designed climate system, thermal protection elements are introduced into the design of the metallurgical crane cabin, such as a heat-reflecting screen of the floor and side wall and double glazing of the front wall. Then a high-temperature industrial air conditioner was selected, the efficiency of which was confirmed by the results of computer simulation. Thus, for a reasonable choice of the climate system of a metallurgical crane cabin, it is required to have rational combination of the methods and means of thermal protection used at the equipment design stage.

Innovative approaches in the organization of closed waste-free production of organic pork using cultural and natural agricultural land

2020 ◽  
pp. 15-25
Author(s):  
Volodymyr Ivanov ◽  
Andrii Onyshchenko ◽  
Liudmyla Ivanova ◽  
Liudmyla Zasukha ◽  
Valerii Hryhorenko
Keyword(s):  
Agricultural Land ◽  
Side Wall ◽  
Front Wall ◽  
Lower Edge ◽  
Metal Mesh ◽  
Two Phase ◽  
Transparent Plastic ◽  
Pork Production ◽  
Young Pigs ◽  
Side Walls

The mobile house for two-phase litter rearing piglets was developed in the conditions of pasture their housing, the feature of which is that its side walls and roof are made in the form of two similar in shape and length of arched panels. In the back wall of the inner shield is a litter box, a self-feeder for piglets, a feed unit for a sow and a wicket, and in the front wall of the outer shield are doors with a wicket. Along with this, all walls and the roof of the litter box are made of transparent plastic, and the wall located near the self-feeding trough is also made perforated. In addition, the lower edge of the side wall of the inner arch-shaped shield has slides in which the lower edge of the side wall of the outer arc-shaped shield is inserted. A house with transformable fences has been developed to rear the young pigs. The structural feature of the house is the presence on the outside of the walls of the bobbins with a metal mesh edged at the bottom with a flexible sleeve. In order to ensure the conditions of gentle etching of the vegetation cover and to prevent damage to the turf of the pasture, the house can be completed with another type of hedge consisting of two hinged sections with doors on each side of the fence. In addition, the horizontal wings are rigidly attached to the hedge and connected by a metal mesh around the perimeter, the size of the cells of which ensures that the grass is eaten but prevents the turf of the pasture from being undermined. The developed devices for camp-pasture and feeding of maternal stock, suckling pigs, weaning pigs, repair and fattening pigs are well suited for year-round closed non-waste organic pork production using cultural and natural agricultural land. Key words: housing, feeding, devices, sows, piglets, young animals, pasture, organic pork.

Analyzing steam transfer though various flame-retardant fabric assemblies in radiant heat exposure

2016 ◽  
Vol 47 (5) ◽  
pp. 853-869 ◽  
Author(s):  
Yun Su ◽  
Jun Li
Keyword(s):  
Thermal Radiation ◽  
Thermal Energy ◽  
Thermal Protection ◽  
Heat Exposure ◽  
Radiant Heat ◽  
Positive Influence ◽  
Air Permeability ◽  
Fabric System ◽  
Layered Fabric ◽  
Nonfatal Injuries

Protection from steam burns is beneficial to reduce the nonfatal injuries of firefighters in firefighting and rescue operations. A new multifunctional testing apparatus was employed to study heat and steam transfer in protective clothing under low-pressure steam and low-level thermal radiation. Single-, double-, and triple-layered fabric assemblies were selected in this experiment. It is indicated that the existence of hot steam weakens the positive influence of the fabric’s thickness, but increases the importance of the air permeability on the thermal protection. The fabric assemblies entrapping moisture barrier can better resist the penetration of steam through the fabric system, and significantly improve the thermal protection in low steam and thermal radiation exposure due to the low air permeability. Additionally, the total transmitted energy ( Qe) and dry thermal energy ( Qd) under low steam and thermal radiation are dramatically larger than that under thermal radiation ( p < 0.05), while hot steam insignificantly reduces the thermal energy during the cooling ( p = 0.143 > 0.05). The understanding of steam heat transfer helps to provide proper guidance to improve the thermal protection of the firefighter’s clothing and reduce steam burns.

scholarly journals APPLICATION OF ABLATION MATERIALSFOR HEAT PROTECTION OF CABINS OF FIRE-FIGHTING MACHINES

2020 ◽  
Vol 9 (4) ◽  
pp. 134-141
Author(s):  
Vladimir Kotenko ◽  
Vladimir Abrazumov ◽  
Mihail Ermochenkov
Keyword(s):  
Thermal Radiation ◽  
Forest Fire ◽  
Forest Fires ◽  
Thermal Protection ◽  
Protective Coatings ◽  
Heat Exposure ◽  
Heat Fluxes ◽  
Main Requirement ◽  
Low Efficiency ◽  
Intense Heat

Forest fires are accompanied by the release of a huge amount of heat, and the temperature at the edge of a forest fire, where firefighting equipment usually operates, reaches 300-700 °C. Fire engines are exposed to intense heat to extinguish forest fires. The main requirement for the design of such machines is the availability of rational thermal protection. Studies of various methods of thermal protection of cabins have showed the possibility of lowering the temperature on the inner surface of the cabin, but these methods show low efficiency. Protection of cabs from thermal radiation is not provided in the new developments of forest fire machines. It is proposed to use pre-preg coatings to protect cabins of forest fire engines. They are successfully used in spacecraft designs. Recent technologies for the production of such materials, developed recently, have significantly reduced the cost of production of these materials. It expands the possibilities of their application for other equipment subjected to intense heat exposure. The calculations have showed that the heat-protective coatings of the cabins made of pre-pregs quickly warm up to acceptable temperatures. However the use of water reserves in the tank of the car to cool the inside of the cabs provides high protection efficiency even at the limiting values of heat fluxes that occur in the fireplace. At the same time, water is not consumed; it is heated, circulating between the tank and the heat exchanger. The proposed method of protecting cabs of fire machines from thermal radiation is original one. It is a subject of further development.

Thermal analysis of a three-layered radiant porous heat exchanger including fluid flow simulation

2013 ◽  
Vol 228 (8) ◽  
pp. 1375-1390 ◽  
Author(s):  
M Sajedi ◽  
SA Gandjalikhan Nassab ◽  
E Jahanshahi Javaran
Keyword(s):  
Thermal Analysis ◽  
Porous Medium ◽  
Heat Exchanger ◽  
Thermal Radiation ◽  
Optical Thickness ◽  
Gas Flow ◽  
Flow Simulation ◽  
Local Thermal Equilibrium ◽  
Outlet Section ◽  
Energy Equations

Based on an effective energy conversion method between flowing gas enthalpy and thermal radiation, a three-layered type of porous heat exchanger (PHE) has been proposed. The PHE has one high temperature (HT) and two heat recovery (HR1 and HR2) sections. In HT section, the enthalpy of gas flow converts to thermal radiation and the opposite process happens in HR1 and HR2. In each section, a 2-D rectangular porous medium which is assumed to be absorbing, emitting and scattering is presented. For theoretical analysis of the PHE, the gas and solid phases are considered in non-local thermal equilibrium and separate energy equations are used for these two phases. Besides, in the gas flow simulation, the Fluent code is used to obtain the velocity distribution in the PHE from inlet to outlet section. For thermal analysis of the PHE, the coupled energy equations for gas and porous layer at each section are numerically solved using the finite difference method. In the computation of radiative heat flux distribution, the radiative transfer equation (RTE) is solved by the discrete ordinates method (DOM). The effects of scattering albedo, optical thickness, particle size of porous medium and inlet gas temperature on the efficiency of PHE are explored. Numerical results show that this type of PHE has high efficiency especially when the porous layers have high optical thickness. The present results are compared with those reported theoretically by other investigators and reasonable agreement is found.

Effect of Ambient Illuminant on Surface Colour Constancy

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 221-221
Author(s):  
I Kuriki ◽  
K Uchikawa
Keyword(s):  
Simple Model ◽  
Spatial Interaction ◽  
Interaction Mechanism ◽  
Side Wall ◽  
Front Wall ◽  
Colour Constancy ◽  
Small Aperture ◽  
Real Environment ◽  
Colour Appearance ◽  
Complete Match

Generally, we are completely enclosed in a real environment, which may act as an entire view-field or adapting field. But in most studies on colour constancy experiments have been made with spatially restricted stimuli. We built a room with gray (N5) walls inside to measure the effect of ambient illuminant on colour constancy. The room illuminant could change its colour from white (D65) to either blue, orange, green, or purple. The observer sat in this main room and adapted to the illuminant for 5 min before the start of the experiment. The observer was shown a smaller room, which had the same variable-colour illuminant, through an aperture (11 deg × 8 deg) in the left side wall. We set the illuminant for each room independently, but in asymmetric illuminant-colour conditions either was set to white. The observer viewed the central part of a colour CRT monitor, placed behind a small aperture (5 deg × 5 deg) in the front wall, and matched its colour appearance to four OSA colour chips in the smaller room. Under symmetric illuminant conditions, eg blue vs blue, the observers' settings showed a complete match with the physical chromaticities of the colour chips. In asymmetric illuminant conditions, eg white vs blue, matched colours showed systematic deviations from both physical chromaticities and colour constancy. This implies that taking the ambient illuminant as adapting field did not yield perfect colour constancy. We introduce a simple model based on incomplete adaptation to the ambient illuminant and a spatial-interaction mechanism, which accounts for our results.

Numerical Simulation of Heat Transfer Characteristics for Two Metallic TPS Structures

2010 ◽  
Vol 156-157 ◽  
pp. 1568-1573
Author(s):  
Hai Yong Liu ◽  
Hong Fu Qiang
Keyword(s):  
Heat Transfer ◽  
Thermal Radiation ◽  
Heat Conductivity ◽  
Radiation Effect ◽  
Thermal Protection ◽  
Heating Temperature ◽  
Three Dimensional ◽  
Metallic Layer ◽  
Internal Cooling ◽  
Thermal Radiation Effect

Two structures of metallic thermal protection system(TPS) for hypersonic vehicle were presented. One model was a multi-layer construction and the other has cavities in the metallic layer. Numerical simulations were conducted on the three-dimensional TPS models using CFD software of Gambit and Fluent. Two heating temperatures of 1073K and 773K with constant temperature and isothermal boundary conditions were considered. Heat transfer was treated as single conductivity and thermal radiation effect was not involved. The results of simulation investigation showed that: The metallic layer had poor capability to restrict the heat conductivity. Heat was easier to transfer across the bracket into the internal part of the TPS. The ability of cavities in metallic layer to resist heat conductivity was limited. The temperature-heating time variation pattern was similar for different external heating temperature. Internal cooling was important for the TPS. The thermal radiation effect on the TPS would be focused in further research.

Study on Stressed Characteristic of Gridding Concrete Retaining Wall Used in Excavation of Soft-Soil Foundation Pit

2011 ◽  
Vol 243-249 ◽  
pp. 2266-2270
Author(s):  
Guang Zhu Zhou ◽  
Xu Wei ◽  
Chen Yu
Keyword(s):  
Retaining Wall ◽  
Soft Soil ◽  
Side Wall ◽  
Building Envelope ◽  
Front Wall ◽  
Soil Pressure ◽  
Back Wall ◽  
Foundation Pit ◽  
Partition Wall ◽  
Finite Element Software

As a new type of building envelope, Gcrw is mainly used for excavation of foundation pit. It can stand by itself without the help of bracing, especially in soft soil area. Its stressed characteristic hasn’t been known yet. By using advanced big finite element software Abaqus/Cae, a simulation was made on model of Gcrw under soil pressure when a foundation pit is dug, while the whole excavation is divided into three continuous independent excavation stages. The result shows that Gcrw is a rather good building envelope, Gcrw and soil in the gridding form an integral earth-retaining structure and keep balance under soil pressure before or behind the structure, and have little displacement in horizontal direction. It is like a gravity-type retaining wall in its entirety, but takes on an elastic characteristic. The soil pressure presents a linear change, but its value is less than the theoretical value of calculation. The front wall of Gcrw, like a sheet, is the main flexural construction element, which is subjected to the pressure from side wall of foundation pit and produce curve deformation. The back wall of Gcrw has little displacement and almost is built in the clay. The partition wall endures the effect of the tensile force, its horizontal deformation increases with the build-in depth’s increasing. The back wall and the partition wall play a very important role in dragging back the front wall, the role of them is similar to a pair of anchor tie. The soil in the gridding not only provides soil pressure, but also can fix the back wall, so it is seen as a part of Gcrw and in favor of the Gcrw’s anti-overturn.

Manufacturing of Inconel 718 Based Honeycomb Panels for Metallic Thermal Protection Systems

2012 ◽  
Vol 710 ◽  
pp. 197-202 ◽  
Author(s):  
Hanamantray Baluragi ◽  
V. Anil Kumar ◽  
K. Narasaiah ◽  
Shibu Gopinath ◽  
P.P. Sinha
Keyword(s):  
Thermal Protection ◽  
Space Shuttle ◽  
Thermal Protection System ◽  
Protection System ◽  
Front Wall ◽  
Honeycomb Core ◽  
Thermal Protection Systems ◽  
Wide Range ◽  
Protection Systems ◽  
Three Point Bend Test

Metallic thermal protection system (MTPS) offers significant improvements over the ceramic based TPS for reentry applications. Space shuttle refurbishment time is estimated to be around 17000 man hours between flights. Metallic based TPS can be fabricated easily and provides wide range of design options for TPS. Adaptability and robustness of metallic thermal protection systems offers the potential for reusability. In this work, a unique manufacturing process has been evolved to realize light weight honeycomb panels through corrugation, laser welding and diffusion brazing of faceplates, where in 50 micron thick Inconel718 foil is used for making honeycomb core and 0.2mm thick Inconel718 foil as faceplates. The compression and three point bend test on these panels have shown no debond between faceplates and honeycomb core. 150x150x5mm size honeycomb panels were coated with YSZ and NiCrAlY based Thermal Barrier Coatings (TBC) and high temperature tests have shown thermal resistance of around 570 °C with front wall temperature of 1186 °C and back wall of 533 °C. Also these panels have been characterized for reusability by the testing of same panel at different heat flux levels. Though it is found that honeycomb panel has shown its integrity without debond a certain acceptable level of degradation in coating is observed. Thus Inconel718 based honeycomb panels with TBC coating are proved for use as thermal protection system for reusable launch vehicle systems.

Sign in / Sign up

Export Citation Format

Share Document