Japanese steel industry have been working on the national project "CO₂ Ultimate Reduction System for Cool Earth 50 (COURSE50)" since 2008, which is one of national projects commissioned by NEDO. The goal of COURSE50 project is to mitigate CO₂ emissions from steelworks by about 30% by (1) technology for reducing iron ore to iron in blast furnace using hydrogen contained in coke oven gas and (2) technology for capturing CO₂ contained in blast furnace gas using unused waste heat in steelworks. Using the knowledge gained from the development of COURSE50 as a foothold, the Japan Iron and Steel Federation will take on the challenge to realize "zero-carbon steel".

Carbonate esters are widely used as electrolytes in commercial lithium-ion batteries and are also attracting attention as promising bio-derived fuels. To obtain systematic understanding of the oxidation and pyrolysis characteristics of three linear carbonate esters, dimethyl carbonate (DMC), diethyl carbonate (DEC) and ethyl methyl carbonate (EMC), based on their molecular structures, their gas-phase reactivities and species evolution were examined using a micro flow reactor with a controlled temperature profile. A first comprehensive chemical reaction model of DMC, DEC and EMC was developed based on literature data. From a comparison of weak flame positions of the three linear carbonate esters, the reactivity of DMC was found to be lower than that of DEC and EMC. Based on a computational heat release rate profile, DEC and EMC showed three-stage reactions driven by thermal decomposition reactions of the fuel, while DMC showed a two-stage reaction. In DEC and EMC oxidation as well as pyrolysis, measured CO₂ and C₂H₄ mole fractions started increasing at low temperatures (around maximum wall temperature of 750 K). This trend, however, did not appear in DMC oxidation nor pyrolysis. These differences in gas-phase reactivity and reactions result from whether the fuel molecular structure consists of an ethyl (or ethyl ester) group or not.

Flammability of carbonate esters, organic solvents often used in Lithium-Ion Battery (LIB), are investigated by using wick-LOC method. The wick-LOC method is a newly developed approach suitable for liquid fuel flammability quantification, which includes wick combustion system and controlling system of the oxygen-nitrogen ratio of external flow. After ignition is attained at the tip of wick soaked with target liquid fuel oxygen concentration in the external flow is gradually decreased up to extinction happens. The limiting oxygen concentration (LOC) to sustain the wick flame is defined as wick-LOC as an indicator of liquid fuel flammability in this work. The wick-LOC of dimethyl carbonate (DMC) is around 15.9% at 10cm/s of external flow velocity and it increases with increase in the external flow velocity. The wick-LOC of ethyl methyl carbonate (EMC) is 1% less than that of DMC. The mixture of EMC and cyclic carbonate ester shows linear change in wick-LOC proportional to the mixing ratio. The addition of organophosphorus compounds (OPCs) as fire retardants results in significant increase in wick-LOC and it is more effective in the range of low OPCs addition. The results of this work provide useful information for the improvement of LIB fire safety.

Two-stage ignition of dimethyl ether (DME)/air mixtures was investigated by using a transparent laminar flow reactor. Ignition and subsequent flame propagation phenomena were captured. Particular attention was paid to the transition from the first-stage ignition to the second-stage ignition. Experiments were performed with the reactor temperature lower than 600 K and equivalence ratio ranged from 0.4 to 4.1. It was found that, under fuel rich conditions, reducing reactor temperature triggered the transition from the first-stage ignition to the second-stage ignition. A transient two-dimensional axisymmetric numerical model considering detailed transport properties and skeletal chemical kinetics was developed to simulate the experiments. The ignition and flame propagation phenomena were reproduced. It was suggested that the intermediate hydroperoxide species hydroperoxy-methylformate (HPMF, HO₂CH₂OCHO) played a critical role in the transition from the first-stage ignition to the second-stage ignition. Higher concentration HPMF was produced and accumulated at a lower reactor temperature due to the prolonged ignition delay time, and its decomposition would produce more OH radicals to promote the transition from the first-stage ignition to the second-stage ignition.

As an HCCI combustion is effective for low NOx and high thermal efficiency, the realization of HCCI engine was expected, however there are many subjects. For example, regular gasoline compositions are different between the oil refineries and fuel production lots, and the HCCI engine performance changes. Further, the maximum pressure rise rate is high even the low load engine operation conditions and the high load HCCI engine operation is difficult. These subjects are caused by the utilization of market fuels, gasoline and diesel fuel, and HCCI research was also conducted by both the engine and chemical researchers. Much research of bio fuels, hydro-refining bio diesel fuel and bio ethanol, was conducted according to the concepts of carbon recycles. Since the ignitability of ethanol is low, the HCCI engine operation with ethanol is difficult, however the RCCI operation with di-methyl ether (DME) and ethanol depending on the engine load and speed is possible. Here, the research of HCCI combustion control by the DME and ethanol, published in 2012 SAE Paper, is introduced and a new concept of HCCI combustion, the dual phase high temperature heat release combustion, is discussed.

Polyoxymethylene dimethyl ethers are a class of ethers with the molecular structure CH₃(-O-CH₂)_n-O-CH₃, called OME for short. Amid a growing global trend for a carbon neutral, OME has attracted the attention as a potential e-fuel for compression ignition engines because it has good ignitability and low-sooting tendency. In this article, the fuel property, the synthesis, the cost, chemical kinetic mechanisms and the effects of OME blends on engine performance are described based on the latest literatures, as well as the research on the spray characteristics made by the authors. The points are as follows: it is not feasible to use neat OME because the cost of OME synthesis is high with the current technology, but to use as diesel fuel additive that can greatly reduce PM emission. Without changing the fuel injection strategy from diesel fuel, the thermal efficiency is penalized with OME blends. The ignition delay and combustion duration decrease with the increasing of OME ratio in the diesel fuel blends. The thermal efficiency could be improved by optimizing the fuel injection parameters.

The two-color pyrometry has been widely used for measurements of flame temperature in combustion devices. The response of this method is enough high to capture the temporal change of flame temperature in the chamber of Diesel engines. The two-color method is based on the measurement of thermal radiation emitted from soot particles formed in a diffusion flame with hydrocarbon fuels. Principle of this method and examples of application of this method are described in this article.

Although the temperature is important information in combustion research and development, it is very difficult to accurately measure the temperature of combustion gases. Thermocouples are inexpensive and traditional measuring tools but careless use leads one completely wrong result. In this lecture, tips for using thermocouples are introduced for beginners, and also several non-intrusive infrared emission methods including CT method for combustion gases are introduced and discussed for better application and accuracy.

Change of velocity distributions, flame structures and pressure fluctuations corresponding to combustion oscillation onset in a methane/air turbulent swirling lean premixed combustion were investigated by simultaneous high-speed measurements of stereoscopic particle image velocimetry (SPIV), OH chemiluminescence and pressure fluctuation. Acoustic forcing was applied to make the coupling systems by means of acoustic interference clear. The transition process towards combustion oscillation was defined based on the root-mean-square (rms) values of pressure fluctuation p'_rms. Experimental conditions on flow rate, equivalence ratio, length of the combustion chamber and a degree of the swirler vane were set so as to be feasible to occur the transition process. Phase-based analyses of physical properties' fluctuation show that the transition process in all cases holds Rayleigh criteria. In the early stages of the transition process, dynamic instabilities were observed in sheer layers. Involved unburnt regions by vorticity growth were found in the latter half stage. Dynamic mode decomposition (DMD) for the velocity distributions around the beginning of the transition process revealed high-frequency asymmetry features in inner recirculation zones and low-frequency asymmetry features in outer recirculation zones.

Aluminum jet flames display both steady and unsteady behaviors that depend on numerous parameters, such as the equivalence ratio and jet flow rate. The identification of combustion regimes poses a challenge due to different combustion behaviors in the same condition. This work applied machine learning, in particular principal component analysis (PCA), clustering, and support vector machine (SVM), to distinguish the combustion behaviors of the aluminum jet flame. First, four features were extracted from high-speed videos of the aluminum jet flame and sound pressure profiles during combustion. These features include the root mean square error of flame shape, the flame oscillation frequency, and the coefficients of variation in flame length and sound pressure. Second, the dimension of the experimentally obtained data was reduced from four dimensions to two dimensions via the PCA. The experimental data was classified into three groups: steady, unsteady, and transition and then labelled by applying the clustering to the processed data. Finally, the highly accurate boundaries between their groups were determined via the SVM. Furthermore, a combustion regime map was obtained by identifying the experimental parameters of some plots near the boundaries, which enables us to predict the combustion behaviors of the aluminum jet flame in a given condition.