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ElsevierGarcía Martínez, A.; Monsalve Serrano, J.; Heuser, B.; Jakob, M.; Pichinger, S. (2016). Influence of fuel properties on fundamental spray characteristics and soot emissions using different tailor-made fuels from biomass. Energy Conversion and Management. 108:243-254. doi:10.1016/j.enconman.2015.11.010.Influence of fuel properties on fundamental spray characteristics and soot emissions using different tailor-made fuels from biomass Energy Conversion and Management, Volume 108, 15 January 2016, Pages 243-254. http://dx.doi.org/10.1016/j.enconman.2015 Antonio García AbstractThis work evaluates the potential of some new biomass-derived fuels as candidates for compression ignition operation. Thus, fundamental spray characteristics related to fuel vaporization and fuel/air mixing process for 2-Methyltetrahydrofuran, Di-n-butyl ether and 1-octanol has been studied and compared with conventional EN590 Diesel fuel. For this purpose, OH* chemiluminescence and shadowgraphy measurements in a high pressure chamber as well as 1D simulations with a spray model have been carried out at different operating conditions representative of the NEDC driving cycle. Finally, measured soot emissions in the singlecylinder engine were presented and discussed.Results from the high pressure chamber presented very good agreement in terms of liquid length and vapor penetration with simulation results. Thus, some analytical expressions related to macroscopic spray characteristics have been proposed and validated experimentally for all four fuels. Finally, the single-cylinder engine results confirmed the relevant role of soot formation on final emissions for 1-octanol and 2-MTHF. In addition, DNBE showed greater soot oxidation potential than diesel and other TMFB candidates.

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In this letter, we describe a technique for determining the Andreev reflection probability of electrons impinging on a semiconductor–superconductor interface. A two-dimensional electron gas (2DEG) in an InGaAs/InP heterostructure is linked to a niobium superconductor. A point contact in the 2DEG emits ballistic electrons and detects the reflected carriers. The vast majority of the detected carriers are retroreflected holes because of our specific sample setup. We have found an Andreev reflection probability of up to 20%. The experimental results are compared with the predictions of two theoretical models.

Recently, several promising biomass-derived fuels for diesel engines have been identified, produced, and tested. Diesel engine experiments confirmed very low soot and low nitrogen oxide emissions. With regard to further improvements of the combustion system, it is desirable to complement the diesel engine experiments with numerical simulations. To date, this is hindered by the lack of suitable chemical reaction mechanisms for these novel fuels. Therefore, a surrogate approach is presented here and applied in computational fluid dynamics simulations. Combustion and pollutant formation is simulated using the representative interactive flamelet model. Ignition, combustion, and pollutant formation are described in a consistent manner by inclusion of detailed reaction chemistry. Different mixtures of n-heptane, toluene, ethanol, dimethylether, ethane, and phenol are employed to describe the combustion chemistry of the biofuels. The compositions of the surrogate fuels are compiled according to hydrogen/carbon ratio, oxygen content, cetane rating, and molecular properties of the experimental fuels. Spray, injection, and evaporation properties of the experimental fuels, as obtained from spray vessel experiments, are included in the computational fluid dynamics simulations. By systematic comparison of experimental and numerical results, the surrogate methodology is validated and an improved understanding of the limitations of the current surrogates is achieved. Thus, a methodology for the fast adoption of novel fuels for simulations is proposed that can be used regardless of the availability of specific chemical reaction mechanisms.

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