Anaerobic digestion is a demanding process, due to the large number of process and environmental factors that affect it. Many years of research of the various parameters have made it possible to optimise the process to obtain the maximum amount of biogas and methane contained in it, and this provides energy and environmental benefits. The article deals extensively with the operation of agricultural biogas plants, using the example of a plant that faces numerous operational problems. In order to identify the negative effects on energy yield and the equipment operating in the system, the substrate was examined, the data on its operation analysed, and solutions were proposed that should be taken into account in the further operation of the biogas plant. The analysis showed a good biogas yield from beet pulp of 563 dm3∙kg-1 of TS (total solid) and an average methane yield of 58%. With the analysis presented, it was possible to identify some operational problems. The biogas yield study also highlighted some errors made at the plant design stage. The most important of these is the use of an inappropriate organic matter loading factor for the digester, which leads to acidification of the contents and degradation of the methanogenic microorganism cultures.
The aim of this study was to investigate and analyse the synchronous reluctance machine. An accurate method for determining the lumped parameters of an equivalent circuit of the studied machine has been proposed. The method is based on the phase currents and voltages analysis at low slip operation. Experimental research of a synchronous reluctance machine is supplemented by simulation studies. The field-circuit model of electromagnetic phenomena in the considered motor was developed and used in simulation. The proposed method allows the numerical model to be verified by comparing the calculated and measured torqueangle characteristics of the machine. The test results obtained are presented and discussed. Achieved satisfactory concordance between simulation and experiment results proves that the proposed approach can be useful in the synthesis of reliable synchronous reluctance machines as well as in their control systems.
The paper focuses on adapting the random cellular automata (RCA) method concept for the unconstrained grain growth simulation providing digital microstructure morphologies for subsequent multi-scale simulations. First, algorithms for the generation of initial RCA cells alignment are developed, and then the influence of cells density in the computational domain on grain growth is discussed. Three different approaches are proposed based on the regular, hexagonal, and random cells’ alignment in the former case. The importance of cellular automata (CA) cell neighborhood definition on grain growth model predictions is also highlighted. As a research outcome, random cellular automata model parameters that can replicate grain growth without artifacts are presented. It is identified that the acceptable microstructure morphology of the solid material is obtained when a mean number of RCA cells in the investigated neighborhood is higher than ten.
Marketplace’y zrewolucjonizowały handel detaliczny w wielu obszarach, stwarzając możliwość zakupu szerokiego spektrum produktów i usług oferowanych w Internecie przez wielu sprzedających z różnych branż. Czy podobne rozwiązania i narzędzia dedykowane dla intralogistyki zmienią rynek magazynowy, a tym samym modele biznesowe producentów i dystrybutorów?
The PZL – 10-turboshaft gas turbine engine is straight derivative of GTD-10 turboshaft design by OKMB (Omsk Engine Design Bureau). Prototype engine first run take place in 1968. Selected engine is interested platform to modify due gas generator layout 6A+R-2, which is modern. For example axial compressor design from successful Klimov designs TB2-117 (10A-2-2) or TB3-117 (12A-2-2) become obsolete in favour to TB7-117B (5A+R-2-2). In comparison to competitive engines: Klimov TB3-117 (1974 – Mi-14/17/24), General Electric T-700 (1970 – UH60/AH64), Turbomeca Makila (1976 – H225M) the PZL-10 engine design is limited by asymmetric power turbine design layout. This layout is common to early turboshaft design such as Soloview D-25V (Mil-6 power plant). Presented article review base engine configuration (6A+R+2+1). Proposed modifications are divided into different variants in terms of design complexity. Simplest variant is limited to increase turbine inlet temperature (TIT) by safe margin. Advanced configuration replace engine layout to 5A+R+2-2 and increase engine compressor pressure ratio to 9.4:1. Upgraded configuration after modification offers increase of generated power by 28% and SFC reduction by 9% – validated by gas turbine performance model. Design proposal corresponds to a major trend of increasing available power for helicopter engines – Mi-8T to Mi-8MT – 46%, H225M – Makila 1A to 1A2 – 9%, Makila 1A2 to Makila 2-25%.
Prezentowany artykuł dotyczy projektowania wstępnego komór spalania silników turbinowych klasy mikro. W odróżnieniu od metodyki projektowania komór spalania dużych komercyjnych silników turbinowych, ich mniejsze odpowiedniki należą do konstrukcji eksperymentalnych. Aby dokonać próby budowy na miarę uniwersalnego modelu obliczeniowego należy zbudować bazę wiedzy która pozwoli na jasne wyznaczenie warunków brzegowych dla przyszłych badań. Niewątpliwą zaletą wzorowania się na istniejących rozwiązaniach jest możliwość szybkiego uzyskania prototypowego rozwiązania, bez konieczności głębszego wnikania w skomplikowany mechanizm spalania paliwa w komorach o małej objętości.
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Presented article is focused on initial design of small scale combustors for micro scale jest engines. In comparison to the full size equivalent, small combustor are design and manufactured in experimental way. To try building universal numeric model for micro size design is important to acquire as many data as possible to identify boundary conditions for a model. Major advantage of analyzing different design is possibility to quick building prototype design without investigating complex process of combustion.
A hybrid artificial boundary condition (HABC) that combines the volume-based acoustic damping layer (ADL) and the local face-based characteristic boundary condition (CBC) is presented to enhance the absorption of acoustic waves near the computational boundaries. This method is applied to the prediction of aerodynamic noise from a circular cylinder immersed in uniform compressible viscous flow. Different ADLs are designed to assess their effectiveness whereby the effect of the mesh-stretch direction on wave absorption in the ADL is analysed. Large eddy simulation (LES) and FW-H acoustic analogy method are implemented to predict the far-field noise, and the sensitivities of each approach to the HABC are compared. In the LES computed propagation field of the fluctuation pressure and the frequency-domain results, the spurious reflections at edges are found to be significantly eliminated by the HABC through the effective dissipation of incident waves along the wave-front direction in the ADL. Thereby, the LES results are found to be in a good agreement with the acoustic pressure predicted using FW-H method, which is observed to be just affected slightly by reflected waves.
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Artykuł podejmuje tematykę nowoczesnych rozwiązań podnoszących poziom bezpieczeństwa na drogach oraz nowatorskich zastosowań powszechnie stosowanej w logistyce technologii RFID. Zaprezentowano w artykule trzy rozwiązania wykorzystujące technologię RFID na potrzeby logistyki miejskiej. Identyfikacja badań technicznych pojazdów, identyfikacja użytkownika pojazdów oraz sterowanie ruchem świetlnym na potrzeby pojazdów uprzywilejowanych – to obszary, które zostały poddane analizie oraz dla których zaproponowano innowacyjne usprawnienia poprzez wykorzystanie technologii RFID.
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The following article is taking the subject matter of high-tech solutions of applications raising the level of the road safety and innovative universally used in the logistics of the RFID technology. In the article presented three solutions about using the RFID technology for the purposes of the urban logistics. The identification of technical inspections of vehicles, the user authentication of vehicles and control the traffic lights to needs of emergency vehicles – these are areas which were analysed and which innovative improvements were suggested by using the RFID technology for.
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