Theoretical investigaion of the performance of alternative aviation fuels in an aero-enginve combustion chamber

When considering alternative fuels for aviation, factors such as the overall efficiency of the combustion process and the levels of emissions emitted to the atmosphere, need to be critically evaluated. The physical and chemical properties of a fuel influence the combustion efficiency and emissions and therefore need to be considered. The energy content of a biofuel, which is influenced negatively by the presence of oxygen in the molecular structure (i.e. oxygenated chemical compounds), is relatively low when compared with that of conventional jet fuel. This means that the overall efficiency of the process will be different. In this paper two possible scenarios have been investigated in order to assess the potential to directly replace conventional jet fuel with Methyl Buthanoate - MB (a short chain FAME representing biofuel) and a synthetic jet fuel (FT fuel) using Computational Fluid Dynamics (CFD) modelling in a typical Modern Air-Spray Combustor (MAC). In addition the impact of fuel blending on the combustion performance has been investigated. Computational Fluid Dynamics (CFD) has been verified and validated over past decades to be a powerful design tool in industries where experimental work can be costly, hazardous and time consuming, to support the design and development process. With recent developments in processor speeds and solver improvements, CFD has been successfully validated and used as a tool for optimizing combustor technology. Combustion of each fuel is calculated using a mixture fraction/pdf approach and the turbulence-chemistry interaction has been modelled using the Laminar Flamelet approach. Detailed chemical reaction mechanisms, developed and validated recently by the authors for aviation fuel including kerosene, synthetic fuel and bio-aviation fuel have been employed in the CFD modelling. A detailed comparison of kerosene with alternative fuel performance has been made.

Assessment of the performance of alternative aviation fuel in a modern air-spray combustor (MAC)

Recent concerns over energy security and environmental considerations have highlighted the importance of finding alternative aviation fuels. It is expected that coal and biomass derived fuels will fulfil a substantial part of these energy requirements. However, because of the physical and chemical difference in the composition of these fuels, there are potential problems associated with the efficiency and the emissions of the combustion process. Over the past 25 years Computational Fluid Dynamics (CFD) has become increasingly popular with the gas turbine industry as a design tool for establishing and optimising key parameters of systems prior to starting expensive trials. In this paper the performance of a typical aviation fuel, kerosene, an alternative aviation fuel, biofuel and a blend have been examined using CFD modelling. A good knowledge of the kinetics of the reaction of bio aviation fuels at both high and low temperature is necessary to perform reliable simulations of ignition, combustion and emissions in aero-engine. A novel detailed reaction mechanism was used to represent aviation fuel oxidation mechanism. The fuel combustion is calculated using a 3D commercial solver using a mixture fraction/pdf approach. Firstly, the study demonstrates that CFD predictions compare favourably with experimental data obtained by QinetiQ for a Modern Airspray Combustor (MAC) when used with traditional jet fuel (kerosene). Furthermore, the 3D CFD model has been refined to use the laminar flamelet model (LFM) approach that incorporates recently developed chemical reaction mechanisms for the bio-aviation fuel. This has enabled predictions for the bio-aviation fuel to be made. The impact of using the blended fuel has been shown to be very similar in performance to that of the 100% kerosene, confirming that aircraft running on 20% blended fuel should have no significant reduction in performance. It was also found that for the given operating conditions there is a significant reduction in performance when 100% biofuel if used. Additionally, interesting predictions were obtained, related to NOx emissions for the blend and 100% biofuel

The course of experimental staphylococcus infection in albino mice during action of certain factors of space flight

A study was made of the effect of certain factors of space flight, acceleration and hypokinesia, on the course of experimental staphylococcus infection in mice. Combined action of hypokinesia and acceleration caused a marked depression of the phagocytic activity of leukocytes and formation of a considerable amount of alpha toxin

Sistem Informasi Monitoring Perkembangan Sapi di Lokasi Uji Performance (Studi Kasus : Dinas Peternakan dan Kesehatan Hewan Provinsi Lampung)

Dinas Peternakan dan Kesehatan Hewan Lampung adalah instansi yang bergerak dibidang pengolahan dan pengembangan hewan yang ada di Provinsi Lampung. Pada Dinas Peternakan dan Kesehatan Hewan Provinsi Lampung monitoring perkembangan sapi dilakukan dengan mengelola data penilaian tumbuh kembang sapi. Data yang digunakan dalam monitoring perkembangan sapi adalah dokumen yang didalamnya terdapat isi atau spesifikasi yang terdiri dari beberapa sapi dalam peternakan, yang termasuk dalam spesifikasi sapi yaitu No. Eartg, nama sapi, jenis kelamin, tanggal lahir, berat badan, tinggi pundak, lebar dada dan panjang badan. Pendataan dan penilaian tersebut dilakukan dengan penulisan di lembaran kertas dan kemudian diarsipkan.Agar monitoring perkembangan sapi menjadi lebih baik, cepat, dan terintegritas maka dibutuhkan sebuah sistem informasi. Pengembangan sistem informasi monitoring sapi ini dimaksudkan untuk membantu pegawai atau Kelompok Jabatan Fungsional dalam proses pengolahan data perkembanganan sapi, khususnya dalam penilaian tumbuh kembang sapi pada saat di Lokasi Uji Perfomance, serta menghasilkan keluaran atau infromasi akurat berupa Laporan Perkembangan Sapi dan Laporan Keseluruhan yang akan diserahkan pada Kepala Dinas. Aplikasi monitoring perkembangan sapi yang dikembangkan dilengkapi dengan informasi spesifikasi sapi pada form perkembangan sapi yang secara otomatis tervalidasi berdasarkan SNI tumbuh kembang sapi pada sistem

Rancang Bangun Sistem Informasi Publik Berbasis Web (Studi Kasus : Desa Durian Kecamatan Padang Cermin Kabupaten Pesawaran)

Pelayanan publik pada dasarnya adalah upaya sebuah organisasi baik langsung maupun tidak langsung untuk memenuhi kebutuhan dengan layanan yang baik. Informasi yang dapat diakses oleh publik dibutuhkan informasi yang cepat dan tepat waktu, tidak terkecuali pelayanan informasi di desa. Di kantor desa Durian Kecamatan Padang cermin Kabupaten Pesawaran mempunyai banyak informasi publik diantaranya mengenai kegiatan desa, bantuan atau hanya sekedar memberikan informasi kepada masyarakat. Salah satu dari pelayanan publik yang bersifat pembuatan surat salah satu contohnya penerbitan (SKTM) Surat Keterangan Tidak Mampu. Proses dalam pelayanan surat-surat yang dibutuhkan oleh masyarakat melalui proses yang panjang. Hal ini dapat membuat proses untuk mengurus surat-surat tersebut terasa berat oleh masyarakat. Selain itu informasi desa hanya melalui mading dan informasi melalui ketua RT. Penelitian ini menghasilkan sebuah sistem informasi publik berbasis web yang dapat mepermudah masyarakat untuk mendapatkan informasi yang dibutuhkan sehingga dapat meningkatkan pelayanan kepada masyarakat

Behaviour of the Blazar CTA 102 during two giant outbursts

Blazar CTA 102 underwent exceptional optical and high-energy outbursts in 2012 and 2016-2017. We analyze its behaviour during these events, focusing on polarimetry as a tool that allows us to trace changes in the physical conditions and geometric configuration of the emission source close to the central black hole. We also use Fermi gamma-ray data in conjunction with optical photometry in an effort to localize the origin of the outbursts.AST-1615796 - Boston Universit

A hierarchy of models related to nanoflows and surface diffusion

In last years a great interest was brought to molecular transport problems at nanoscales, such as surface diffusion or molecular flows in nano or sub-nano-channels. In a series of papers V. D. Borman, S. Y. Krylov, A. V. Prosyanov and J. J. M. Beenakker proposed to use kinetic theory in order to analyze the mechanisms that determine mobility of molecules in nanoscale channels. This approach proved to be remarkably useful to give new insight on these issues, such as density dependence of the diffusion coefficient. In this paper we revisit these works to derive the kinetic and diffusion models introduced by V. D. Borman, S. Y. Krylov, A. V. Prosyanov and J. J. M. Beenakker by using classical tools of kinetic theory such as scaling and systematic asymptotic analysis. Some results are extended to less restrictive hypothesis

Melting Point and Lattice Parameter Shifts in Supported Metal Nanoclusters

The dependencies of the melting point and the lattice parameter of supported metal nanoclusters as functions of clusters height are theoretically investigated in the framework of the uniform approach. The vacancy mechanism describing the melting point and the lattice parameter shifts in nanoclusters with decrease of their size is proposed. It is shown that under the high vacuum conditions (p<10^-7 torr) the essential role in clusters melting point and lattice parameter shifts is played by the van der Waals forces of cluster-substrate interation. The proposed model satisfactorily accounts for the experimental data.Comment: 6 pages, 3 figures, 1 tabl

Analysis of particle production in ultra-relativistic heavy ion collisions within a two-source statistical model

The experimental data on hadron yields and ratios in central lead-lead and gold-gold collisions at 158 AGeV/$c$ (SPS) and $\sqrt{s} = 130$ AGeV (RHIC), respectively, are analysed within a two-source statistical model of an ideal hadron gas. A comparison with the standard thermal model is given. The two sources, which can reach the chemical and thermal equilibrium separately and may have different temperatures, particle and strangeness densities, and other thermodynamic characteristics, represent the expanding system of colliding heavy ions, where the hot central fireball is embedded in a larger but cooler fireball. The volume of the central source increases with rising bombarding energy. Results of the two-source model fit to RHIC experimental data at midrapidity coincide with the results of the one-source thermal model fit, indicating the formation of an extended fireball, which is three times larger than the corresponding core at SPS.Comment: 6 pages, REVTEX

Contact orderability up to conjugation

We study in this paper the remnants of the contact partial order on the orbits of the adjoint action of contactomorphism groups on their Lie algebras. Our main interest is a class of non-compact contact manifolds, called convex at infinity.Comment: 28 pages, 1 figur