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The blast furnace smelting of vanadium–titanium ore plays a crucial role in the efficient utilization of vanadium-titanium resources. In this research, a detailed numerical simulation study of the temperature, velocity, and concentration fields during the smelting process in a vanadium–titanium blast furnace was conducted. The actual production data from a 1750 m3 vanadium–titanium blast furnace was utilized, combined with softening and dripping parameters and material balance calculations, to develop a two-dimensional blast furnace model. This model was employed to analyze the effects of varying smelting intensities on the internal operating conditions of the furnace. The study found that as smelting intensity increased, significant changes occurred in the temperature fields and CO concentration fields within the furnace, thereby affecting the reduction efficiency of the burdens. Additionally, this research also shows that increasing the proportion of Baima pellets in the furnace will lead to the expansion of the soft melting zone and the upward movement of the soft melting zone. This investigation not only revealed the variations in the internal physical fields of the blast furnace under different operating conditions but also provided theoretical foundations and references for optimizing the design and operation of vanadium–titanium blast furnaces. By comparing the velocity field under different smelting intensities, it was found that the difference was small, which was mainly related to the expansion behavior of the pellets. These findings provide an important scientific basis for further improving the efficiency of blast furnace smelting and reducing costs. [ABSTRACT FROM AUTHOR]

Acoustic tomography utilizes sensor arrays to collect sound wave signals, enabling non-contact measurement of physical parameters within an area of interest. Compared to optical technologies, acoustic tomography offers the advantages of low cost, low maintenance, and easy installation. Current research in acoustic tomography mainly focuses on reconstruction algorithms for temperature fields, while monitoring the composition and concentration of gases is significant for ensuring safety and improving efficiency, such as in scenarios like boiler furnaces and aviation engine nozzles. In excitable gases, the speed of sound exhibits an S-shaped curve that changes with frequency, a characteristic that could be potentially useful for acoustic tomography. Therefore, this study primarily discusses the quantitative calculation of gas concentration and temperature based on the dispersion of the speed of sound. By employing graphic processing and pattern matching methods, a coupled relationship of the dispersion of the speed of sound with gas concentration and temperature is established. The projection intersection method is used to calculate the concentration and temperature of binary and ternary gas mixtures. Combined with the inversion method, a joint reconstruction method for gas concentration fields and temperature fields based on the dispersion of the speed of sound is developed. The feasibility of the proposed simultaneous reconstruction method for temperature and concentration fields is validated using numerical simulations. Additionally, an acoustic tomography experimental system was set up to conduct reconstruction experiments for binary gas concentration fields and temperature fields, confirming the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

In order to solve the problem of spontaneous combustion of coal in U-shaped stope during dynamic advance, a multiphysical field coupled mathematical model including the inlet and return airway, working face and goaf is established, and the reasonableness of the model is verified by field measurement data. The simulation analyzed the law of temperature field and oxygen concentration field in the goaf with the dynamic advance of working face, and further studied the influence of surrounding rock temperature, air flow temperature and working face advance speed on the self-heating of coal oxidation in the mining area. The results indicate that the temperature field on the inlet side of the goaf forms the phenomenon of high temperature region tailing in the shape of “wing section” in the process of advancing the working face, and the temperature of the high-temperature area gradually decreases under the effect of compaction of the goaf and heat dissipation of the surrounding rock; the temperature in the goaf continues to rise after the stoppage of mining, but the high-temperature area migrates to the working face; in the early stage of mining, different ventilation temperature has almost no effect on the maximum temperature in the mining area, while in the later stage of mining, the higher the ventilation temperature, the higher the maximum temperature in the mining area; the faster the working face advances, the lower the maximum temperature in the mining area.

Liquefied natural gas (LNG) is a kind of clean energy, and many LNG-powered vessels have been designed and built around the world. However, LNG introduces the potential risk of leakage and explosion accidents; thus, it is necessary to conduct safety assessments on the layout of typical facilities during the initial design stage. In this paper, an on-deck LNG fuel area model is established by employing the computational fluid dynamics (CFD) method according to an LNG-powered Aframax oil tanker. The distribution of potential dangerous areas on the concentration field and temperature field is presented under leakage and diffusion accident conditions with vent masts of different heights. The results show the following: the gas concentration rises rapidly at the initial stage of leakage and tends to stabilize after a certain period; the leakage and diffusion trend of light gas is basically the same as that of heavy gas, and the lowest heavy gas and light gas temperature on the deck between the storage tank and the upper building is -7.9 C and 4.7 °C, respectively, when the venting mast leakage point is at the height of 6 m; and the higher the mast leakage point is, the more safe the ship design. For safety considerations, the height of the venting mast designed in this paper should not be lower than the height of the LNG storage tank, which is 10 m.

The flue gas temperature of the Smelting Reduction Vessel (SRV) in the HIsmelt process is high while the temperature of the molten iron is low. Therefore, the heat transfer efficiency between the upper and lower regions in the SRV needs to be further improved. The fluid flow and heat transfer characteristics inside the SRV were studied to derive the mass fraction, temperature distribution, and gas motion. The error between the simulated and measured values remained stable within 5%. The gas in the centre of the SRV shows a high-speed vortex flow. The combustion reaction mainly occurs in the centre of the furnace. Since the heat transfer in the furnace is mainly influenced by the gas flow, the high-temperature zone shows a U-shaped distribution and is mainly around the centre of the region, the oxygen lance outlet, and the furnace wall. [ABSTRACT FROM AUTHOR]

Abstract A novel reconstruction model based on inverse radiation analysis was presented for simultaneous estimation of temperature and concentration fields of soot and multiple metal-oxide nanoparticles in nanofluid fuel flame from the knowledge of the flame emission radiation intensity obtained by a CCD camera. The self-absorption effect was considered in the reconstruction model and least-square QR decomposition (LSQR) algorithm combined with iterative method was introduced to solve the inverse radiation problem. The inverse reconstruction model was successfully applied in the flames containing two and three kinds of metal-oxide nanoparticles from simulation values as examples and can be extended to more kinds of metal-oxide nanoparticles containing system. The measured data were also simulated by adding random noise into the exact solution of the direct problem. The numerical results showed that all the unknown parameters fields can be estimated accurately, even with the noisy data. [ABSTRACT FROM AUTHOR]

Abstract The inverse reconstruction method for the simultaneous estimation of temperature and concentration fields of soot and metal-oxide nanoparticles in asymmetric nanofluid fuel flame was improved by considering the self-absorption. The correction method to deal with the self-absorption in axisymmetric sooting flame for obtaining the unattenuated radiation intensity from the attenuated one detected by CCD camera was successfully extended to apply in asymmetric nanofluid fuel flame. These combustion parameters distributions can be concurrently deduced from the knowledge of the unattenuated radiation intensity using least-square QR (LSQR) decomposition and iterative methods. Self-absorption influences on the reconstruction accuracy in flames with different optical thicknesses were investigated and various levels of measurement errors were added into the simulation values from the practical experiment standpoint. The numerical results showed that the relative reconstruction errors of all the unknown parameters fields greatly reduced if self-absorption was considered in the reconstruction method. Moreover, as for the flame with larger optical thickness, the improvement of reconstruction accuracy was more significant. [ABSTRACT FROM AUTHOR]

Highlights • An inverse radiation analysis in asymmetric nanofluid flame was presented. • Temperature and concentration profiles of soot and metal-oxide were estimated. • More grid number resulted in higher reconstruction resolution but lower accuracy. • Reconstructed results were convincing even with signal to noise ratio 46 dB. Abstract An inverse analysis based on the flame emission spectrum technique is presented for the simultaneous reconstruction of two-dimensional (2D) temperature and concentration fields of soot and metal-oxide nanoparticles in the asymmetric nanofluid fuel flames by means of CCD cameras. Four CCD cameras located around the flame cross-section were used to capture the line-of-sight flame emission radiation intensities which were disintegrated to determine the radiation emission source by Least Squares QR algorithm (LSQR) algorithm. The flame cross-section was uniformly divided into several sub-squares with various grid numbers and the relationship between the grid number and the reconstruction precision was investigated in details. Considering the tradeoff between reconstruction resolution and accuracy, the optimal grid number was chosen to be 10 × 10. Satisfactory estimate of the three unknown fields obtained even with the signal to noise ratio of the measurement system as low as 46 dB. Numeral analyses show that the proposed reconstruction method is effective and robust for concurrent reconstructing the temperature and concentration profiles of soot and metal-oxide nanoparticles in the asymmetric nanofluid fuel flames. [ABSTRACT FROM AUTHOR]

The concentration, temperature, and velocity fields of the gas fluxes during gas combustion in the heating channel are calculated on the basis of the mathematical model for a coke oven with a dust-free cokedischarge system. The influence of the air excess and the gas dynamics in the furnace wall on the concentration of combustion products is studied. [ABSTRACT FROM AUTHOR]

The three-dimensional unstable non-linear coupled mathematical model on the underground coal gasification with free channel is established in this article. The determination methods for the major model parameters are explained. Adopting the SIMPLE method, the numerical solution of the mathematical model is found. Additionally, the patterns of variation and development for the temperature field, concentration field and pressure field in the gasification panel are studied. On the basis of the model test, the calculation results are analyzed. Research shows that calculated values of the temperature field are a little higher than the experimental ones, and the relative error for every measuring point is virtually within 16%. Also, a good conformity takes on between the experimental values for the concentration field of the gas compositions and the calculated ones. The simulated results indicate that the relative calculation error of the pressure field is 10.20%–19.44%. Through the analysis of measured data, the change mechanisms of the gas compositions, heating value and pressure field in the underground gasification with free channel are pointed out. [ABSTRACT FROM AUTHOR]

According to the characteristics for combustion and gasification reactions occurring in the gasification gallery, the mathematical functional relationship between the chemical reaction rate and every influencing factor is studied. The dynamic nonlinear coupling mathematical models on underground coal gasification of inclined seams are established. The determination methods of major model parameters are introduced. Additionally, the control volume method is adopted to find the numerical solution to the mathematical models. The patterns of development and variation for temperature field, concentration field and pressure field in gasification panel are studied. On the basis of the model test, calculation results are analyzed. From the distribution of temperature field, its calculation value is a little higher than the experimental one, with the relative error of every measuring point virtually within 17%. Research shows that, the experiment value of gas heat value and calculated value take on a good conformity; due to the influence of temperature, in the high temperature zone, the change gradient of the experiment value for concentration field of gas compositions is greater than that of the calculation value. The simulated results indicate that the relative error of the pressure field calculation is 4.13%-12.69% and 8.25%-17.47%, respectively, 7 h and 45 h after the ignition. The drop rate for the fluid pressure is 6.01% and 10.91%, respectively. Research shows that the simulated values conform with experimental values comparatively well, which demonstrates that the numerical simulation on the "three fields" in underground coal gasification is correct. [ABSTRACT FROM AUTHOR]

The gas production process in underground coal gasification is closely linked to the temperature distribution and seepage conditions of the gasifier. In this paper, mathematical models on the underground coal gasification in steep coal seams are established according to their storage conditions and features of gas production process. Additionally, the paper introduces ways to determine model parameters and the control volume method to solve the model. On the basis of the model experiment, the calculation results are analyzed. From the distribution of temperature field, the calculation value is slightly higher than measurement one. The relative errors of all measuring points are virtually within 10%. According to the simulated calculation results, with the increase of the length for the gasification channel, the heating value of the gas improves. However, behind the reduction zone, it increases with a smaller margin. The influence of the temperature field on the heating value for the gas is noticeable. Due to the effect of temperature, in high temperature zone, the change gradient of the measured value of the concentration field for the gas compositions is larger than that of calculated value. The simulated results of the pressure field in the gasification panel 22 and 75 h after the ignition indicate that the relative calculation errors are 5.00–14.29 and 9.68–17.24%, respectively, with a corresponding pressure drop rate of 9.5 and 11.97%. On the whole, the simulation value conforms with the experiment value, which supports the numerical simulation on the temperature field, concentration field and pressure field of underground coal gasification in the steep coal seams is correct. Thus, it lays a necessary and scientific theoretical foundation for further quantitatively studying the process of underground coal gasification and forecasting the change patterns. [Copyright &y& Elsevier]

Ren, J.; Wang, L.; Huang, Z.; Wang, X.; Li, H., and Lu, J., 2020. Simulation of the 3D structure of pollutants invading sea areas based on 3DLIF technology—A case study of the round tube jet. In: Liu, X. and Zhao, L. (eds.), Today's Modern Coastal Society: Technical and Sociological Aspects of Coastal Research. Journal of Coastal Research, Special Issue No. 111, pp. 49–55. Coconut Creek (Florida), ISSN 0749-0208. Marine pollution is becoming increasingly severe with social and economic progress. The present study adopted the three-dimensional (3D) laser-induced fluorescence technology and used Rhodamine 6G and Rhodamine B fluorescent dyes to simulate the 3D structure of pollutants discharged in the form of a jet. We obtained the scalar field information, conducted 3D reconstruction, and could output the concentration and temperature fields of any cross section. Moreover, we observed and studied the structure and characteristics of the diffusion of pollutants from different perspectives based on the measurement results, and provided theoretical recommendations for the reduction and effective control of marine pollution. [ABSTRACT FROM AUTHOR]