Papers by Keyword: Physical Modeling

Abstract: Land use changes can affect the flow of energy in the soil-atmosphere system, impacting the urban heat island (UHI) effect. Since the climate conditions of Campos dos Goytacazes are changing (becoming drier and warmer), the city was chosen as a study area. This research aims to investigate the behavior of surface energy fluxes and their impact on the UHI and discomfort index (DI) by simulating different surface condition scenarios for the warmest day of 2019. The weather research and forecasting model was used to simulate three scenarios: in the first simulation, anthropogenic heat was excluded, and no green roofs were added; in the second simulation, anthropogenic heat was included without green roofs; and in the third simulation, both anthropogenic heat and green roofs were included. The results showed that anthropogenic heat intensifies the UHI and increases the DI. The effect of green roofs covering 50% of the urban area can reduce the nocturnal effects of the UHI caused by anthropogenic heat, but it does not significantly impact the DI.

Abstract: Nowadays, smart materials with special functional properties, in particular shape memory alloys, are widely used in more and more units of various equipment. Fe-based alloys of the Fe-Mn-Si-Cr-Ni-X system, due to their relatively low cost and sufficiently high manufacturability, can be widely used in various fields. It is shown that in the studied alloys, alloying elements can be divided into system-forming (10–30 wt.% Mn and 3–10 wt.% Si), and additional (Cr, Ni, V, N, Cu, etc.) elements, which add to improve the shape memory effect. It is shown that the one problem of Fe-SMAs is the evaporation of manganese in the melting. Criteria for the selection of alloys considering the temperature regime of melting with minimal evaporation of manganese and satisfactory overheating above the liquidus temperature have been developed. The Fe-35Mn-8Si alloy were produced at laboratory scale. The effect of the cooling rate during solidification on the structural heterogeneity of the test ingots poured into a cast iron chill mold and into a sand mold is studied. Using pin molds, in which conditions are created that inhibit the shrinkage of the solidifying ingot and provoke cracking, their resistance to hot cracks has been studied. The secondary dendrite arm spacings and the segregation coefficients of manganese and silicon were determined depending on the crystallization conditions. Critical parameters of the technology have been determined, the optimization of which makes it possible to produce Fe-SMAs at industrial scale.

Abstract: With the increasing requirements for steel quality, the refining conditions are increasing strict. The high-speed movement of molten steel under mechanical or pneumatic agitation can uniform the temperature and composition, and accelerate the collision of the inclusions to eliminate. However, the electromagnetic field has an important influence on the removal of inclusions in steel and the corrosion of refractory materials. The magnetic phenomenon caused by the movement of molten steel needs to be explored. Considering the complexity of high temperature thermal simulation, this work adopted the physical modeling combined with mathematical simulation method, saturated sodium chloride solution was selected to simulate molten steel as a liquid electrolyte, the magnetic phenomenon caused by solution motion was tested and analyzed, and mathematical model of solution motion magnetization was based on discharge mechanism and magnetic vector potential superposition principle, then the variation law of spatial magnetic field generated by liquid electrolyte flow was discussed. The results show that the simulation results agree with that of the physical modeling, and the mathematical model is promising for prediction of the magnetic field generated by liquid electrolyte flow. Under a constant flow speed of 2000 r/min, a magnetic field with magnetic flux density up to 0.15 Gs was produced, which has a significant effect on the refractory corrosion and removal of impurities in the molten steel.

Abstract: In the work were set and solved the task of the FEM simulation process, the screw firmware blank on the double roller mill with mushroom-shaped rolls. The decision of the task allowed us to calculate the parameters of the contact surface of the workpiece to roll as well as the analysis of dimensional accuracy of the casings. The adequacy of the models is proved by comparison of calculated and experimental values of the parameters of the contact surface and the sizes of the casings. Implementation of the developed technical solutions for adaptation of a piercing mill in the shop No1 PJSC "STZ" has allowed to provide high stability of the rolling of thin-walled shells with size 328×433 of 20.55 mm x 26,9 mm.

Abstract: The deformation behavior of 1565ch alloy under the plane-strain conditions in the temperature range of 350–490 ^оС and strain rates range of 0,1–10 s^-1 is studied. The expression for steady flow stress as the functions of temperature of deformation and strain rate is obtained. It is established that 1565ch alloy with zirconium addition shows higher strain resistance and less tendency to dynamic and static recrystallization than AMg6.

Abstract: The paper displays the description of the method to assess coal seam filtration properties in a bottom-hole zone by physical imitation and use of equivalent materials. The evaluation function of permeability and filtration properties change in a bottom-hole zone was specified under conditions of Taldinskiy coal deposit in Kuzbass.

Abstract: The use of monocoagulants, such as Chitosan, may not be a good solution for highly turbid water purification because of its high cost. The possibility to reduce the amount of the primary coagulant at the same time keeping the removal to be in optimum may be a good strategy to reduce the operation cost. There might be another coagulant aid for example the natural clay of Bentonite to reduce the cost. The initial stage is to determine the Bentonite dosage and mixture ratio to be used with Chitosan. Coagulation of Chitosan-Bentonite had successfully removed the turbidity with the efficiency of 97%. The coagulants performed well when Chitosan-Bentonite ratio is 30:70 at concentration of 1000mg/l

Abstract: A mathematical model has been constructed for simulating the RH degasser of an iron and steel Co. Ltd. The flow field of molten steel in the ladle has been investigated; in addition, it is also investigated through physical modeling study. The main objective of the investigation was to assess the influence of gas flow rate and immersion depth on dead zones in the ladle. The results show that the flow pattern of molten steel in RH degasser can be well represented by the mathematical model and the physical model. Except the areas close to the free surface and the zones between the two snorkels and the sidewall in the ladle, these dead zones can be reduced by increasing of gas flow rate and immersion depth. These dead zones were marked with 1, 2, 3, results calculated by mathematical modeling are in good agreement with which obtained by means of physical modeling (water modelling) study increasing of immersion depth could markedly reduce the area of dead zone 3, yet the area of dead zone 1 and 2 could be markedly reduced by increasing the gas flow rate, hence indicate that mixing of dead zones could be intensified through improving gas flow rate and immersion depth.

Abstract: The research presented in the paper was carried out for the experimental steels with modified chemical composition allocated to pipelines for 760÷1180 °C range, strain rate s^–1 s^–1 and different distributions of particular reductions between passes were presented. Physical modeling of the rolling process was carried out upon using the GLEEBLE 3800 simulator. The research was based on the findings of the paper [1].

Abstract: The paper presents the results of physical modelling aimed at determining the cracking susceptibility of the selected steel grade under conditions characteristic of the continuous casting process. The material used for investigation was steel grade S355J2G3 [1]. For a study on the physical modelling of the continuous steel casting process, the GLEEBLE 3800 [2, 3], a metallurgical process simulator, was employed. The obtained results allowed establishing conditions for a continuous steel casting process that could cause cracks to form in the material being cast. Research on one of technological conditions for steelworks was carried out taking into account the problem of cracking during rolling in the initial group of the bar rolling mill.