Biomass Combustion Control in Small and Medium-Scale Boilers Based on Low Cost Sensing the Trend of Carbon Monoxide Emissions

The effect of the nitrocarburizing process in pastes with heating in a chamber furnace on the struc-ture and strength characteristics of 09Cr15Ni8Al corrosion-resistant steel was investigated. The tech-nology of chemical-thermal treatment was developed, which included nitrocarburizing in pastes with heating in a chamber furnace at different holding times. The thickness of the diffusion layer and its microhardness were determined after nitrocarburizing. To determine the efficiency and select the modes of chemical-thermal treatment, tests were carried out for the investigated steel's strength characteristics. The main feature of the structure of the diffusion layers of valve steels, obtained by nitrocarburizing in the nitrogen-carbon paste, is the presence of an inhomogeneous layer with clearly distinguished zones

Modeling of Technological Processes for a Rectification Plant in Second-Generation Bioethanol Production

The article deals with the recent developments in the fuel industry, considering the permanent increasing requirements for fuel quality and environmental safety. The work aims to study various technological modes at the rectification unit to produce fuel bioethanol from lignocellulosic biomass. The main goals are to solve applied scientific problems of rational designing and technological optimization to obtain boundaries of energy consumption to ensure the quality of bioethanol sufficient for a consumer. Recent approaches for numerical simulation of chemical technological processes were applied to study the operating processes and optimize technological parameters. The plant model was designed from various modules that allow us to simulate technological processes efficiently and accurately for all the primary units of the rectification equipment. The methodology based on the activity coefficient UNIFAC model of phase equilibrium was applied. As a result, a mixture with 74% of bioethanol 9% of impurities was obtained in the brew column. In the epuration column, a mixture of 46% bioethanol and 2.2% of impurities was obtained in bottoms. Finally, in the alcohol column, the mass fraction of distillate of 96.9% and impurities of 2.7% were reached. The numerical simulation results can be applied in recent fuel technologies and designing the corresponding biofuel plants

Динамічне моделювання теплообміну через зовнішні будівельні конструкції

У статті представлені теоретичний і числовий підходи до динамічного моделювання теплообміну через зовнішні будівельні конструкції. У результаті розроблено модель динаміки теплопередачі через стіну на основі математичного моделювання енергетичного балансу елементарного шару плоскої стінки. Стіна розглядалась як суцільне середовище з безперервно розподіленим тепловим опором і ємністю. На основі розробленого аналітичного підходу, що реалізує запропоновану математичну модель, розроблено імітаційну модель із застосуванням середовища MATLAB/Simulink. Продемонстровано динамічну модель теплопередачі через стіну з параметрами реальних матеріалів, а також через вікно з реальними тепловими параметрами. Результати моделювання представлені графічно.In the paper, some approaches to dynamic modeling of heat transfer through external building constructions are presented. The model of heat transfer dynamics through a wall was designed on the base of mathematical describing of an energy balance for the elementary layer of a plane wall. The wall was considered as a continuum with continuously distributed thermal resistance and capacity. Based on the designed analytical mathematical model, a simulation model in MATLAB/Simulink environment was developed. These dynamic models of heat transfer through the wall with real materials parameters and also through the window with real thermal parameters were simulated and some simulation results are presented in the paper

Numerical Simulation of Gas Flow Passing through Slots of Various Shapes in Labyrinth Seals

Labyrinth seals are widely used in centrifugal compressors, turbines, and many other pneumatic systems due to their simplicity of design, reliability, and low cost. The calculation scheme for the movement of the working medium in a labyrinth seal is constructed by analogy with the movement of the working medium through holes with a sharp edge. Annular and flat slots, holes, and such a factor as the shaft rotation with a calculated sector of 3 degrees were studied. The purpose of the study is to determine the flow coefficient when the working medium flows through slots of various shapes. To achieve this purpose, modeling of the working medium flow in the FlowVision software was performed. The mass flow and flow coefficients are determined for the studied slot shapes. The convergence of the calculation results was determined by comparing the values of the mass flow rate at the inlet and outlet of the slot. Differences in visualizations of the flow for the studied variants of slots were established. The resulting difference should be taken into account in practical calculations of the working medium mass flow through the slot using a conditional flow rate factor which is determined by the slot design

Using Regression Analysis for Automated Material Selection in Smart Manufacturing

In intelligent manufacturing, the phase content and physical and mechanical properties of construction materials can vary due to different suppliers of blanks manufacturers. Therefore, evaluating the composition and properties for implementing a decision-making approach in material selection using up-to-date software is a topical problem in smart manufacturing. Therefore, the article aims to develop a comprehensive automated material selection approach. The proposed method is based on the comprehensive use of normalization and probability approaches and the linear regression procedure formulated in a matrix form. As a result of the study, analytical dependencies for automated material selection were developed. Based on the hypotheses about the impact of the phase composition on physical and mechanical properties, the proposed approach was proven qualitatively and quantitively for carbon steels from AISI 1010 to AISI 1060. The achieved results allowed evaluating the phase composition and physical properties for an arbitrary material from a particular group by its mechanical properties. Overall, an automated material selection approach based on decision-making criteria is helpful for mechanical engineering, smart manufacturing, and industrial engineering purposes