Intensification of heat and mass transfer and dewatering of thermolabile organic materials

Ukraine has a high level of industry, agriculture and consumption. As a result of underutilization of recovered materials and their products into the environment returns significant amount of waste that contaminate soil, water, air. Dumps occupy large areas, long ground beneath them put out of production, they pollute the environment. The main causes of waste, lack of effective processes and capacities of processing residues, spatial and chronological dissociation processes of waste and their use, lack of sufficient market. Of all the organic waste in Ukraine is one of the main places belong chicken droppings. Fresh droppings quickly oxidizes the soil, humus and inhibits microorganisms, disrupting its natural ecosystem biological community. With some preparation and processing of chicken manure is a high quality fertilizer that contains chemical elements (N, P, K), macro- and micronutrients, humic acid and other components that are essential for growth and fertility of different plants. For decontamination litter widely used thermal drying at t = 600 – 800 °C. This product is well kept dry, easily transported, but using traditional drying facilities for its handling used large amount of heat. Today continually created and offered new modern technologies for processing chicken manure. At the Institute of Engineering Thermophysics NAS of Ukraine many years conducted investigations on the creation of modern technologies and equipment for processing organic waste. Analysis of the traditional intensification methods and processes of heat and mass transfer during drying of materials was presented in the paper. The author has proved the promising nature of the method of the combined processes of drying and dispersion using a mechanical rotor to intensify the process of drying of high–moisture thermolabile materials.

Analysis of the practical reform of engineering thermal physics teaching based on FLUENT

Engineering thermophysics is a technical science which studies the law of energy transformation in the form of heat and its application.It studies the internal laws of various thermal phenomena and thermal processes, and can be used to guide engineering practice. FLUENT is a tool course that plays a great role in assisting with the simulation of some devices in engineering thermophysics and fluids. However, in the process of learning simulation, students have had difficulty in mastering the FLUENT software and this paper proposes some constructive suggestions for measures to increase students' mastery of this software.

Experimental studies of burning plant pellets in a domestic boiler

In recent years, biofuels have increasingly been used as fuel in Ukraine. Ukraine is an agro-industrial country with great potential for the production and use of pellets of plant origin. Our country ranks 6th in the world for the production of such biofuels as pellets, but most of them (about 85 %) are exported abroad. This is due to the low demand for pellets in the domestic market. Cereal straw can be used in municipal energy. The amount of straw left after harvest is sufficient for its use as fuel. This biofuel in its composition and calorific value is close to such traditional fuels as wood and peat. Also, raw materials for bio-pellets can be sunflower husks and energy crops. The main objectives of this work are experimental studies of the combustion of different types of agropellets. An experimental installation of a solid fuel boiler with a pellet burner was developed and implemented at the Institute of Engineering Thermophysics of the National Academy of Sciences of Ukraine to study the peculiarities of pellet combustion. With the help of the developed measurement system based on a comb with thermocouples, which is located above the torch in the boiler, the temperature regime in the boiler volume was studied and the peculiarities of the pellet burning process in the burner were determined. As a result of the work, experimental studies of the peculiarities of burning pellets of agricultural origin, namely straw (barley, wheat) and pellets from corn cobs were carried out. On the basis of the constructed graphic dependences the characteristic features of temperature modes of work of a household copper at burning of agropellets were defined. The use of the results is possible in the communal and industrial heat energy, social and budgetary sphere and individual household sector.

Improvement of environmental conditions by applying heat recovery technologies of boiler plants

Purpose. Analysis of the effectiveness of using methods of heat and humidity treatment of flue gases to improve the operational modes of chimneys for heating gas-consuming boiler plants with heat recovery systems. Methodology. The known normative methods of thermal calculation of boiler plants and methods of dispersion of pollutants emitted by chimneys of these plants were used. To determine the thermal and moisture parameters of flue gases during their deep cooling, an original method developed at the Institute of Engineering Thermophysics of the National Academy of Sciences of Ukraine was used. Findings. The efficiency of applying the proposed thermal methods to improve environmental conditions and magnification of the operational reliability of chimneys of boiler plants equipped with systems for deep heat recovery of exhaust gases has been studied. The methods which are usually used in boiler-houses to prevent condensate formation in chimneys were considered. Adecrease in the maximum ground-level concentration of nitrogen oxides and carbon monoxide emissions was determined when using these methods. A comparative analysis of the effectiveness of the proposed methods for brick and metal chimneys in different modes of operation of heating boiler plants has been carried out. It is shown that these methods allow improving significantly (up to 32%) the indicators of ecological efficiency of chimneys in conditions of 58% reduction of fuel use in boilers. Originality. For the first time to improve the environmental performance of chimneys of boiler plants with deep heat recovery systems of flue gases has been justified the use of thermal methods of their heat and moisture treatment. Practical value. The possibility of using the results of the work in the design of heat recovery systems for gas-consuming heating boilers.

BIOCARBON AS AN EFFECTIVE SOLID FUEL FROM BIOMASS

We present the results of technical – and – economical analysis showing that the most efficient fuel from biomass for thermal power engineering is bio carbon, which is produced with the help of industrial facility developed and manufactured at the Institute of Engineering Thermophysics of Ukrainian National Academy of Sciences.

Development and Validation of Aerodynamic Measurement on a Horizontal Axis Wind Turbine in the Field

Aerodynamic measurement on horizontal axis wind turbines in the field is a challenging research topic and also an essential research method on the aerodynamic performance of blades in real atmospheric inflow conditions. However, the angle of attack is difficult to determine in the field due to the unsteadiness and unevenness of the inflow. To study the measuring and analyzing method of angle of attack in the field, a platform was developed based on a 100 kW wind turbine from the Institute of Engineering Thermophysics (IET) in China in this paper. Seven-hole probes were developed and installed at the leading edge to measure the inflow direction, static and total pressure at the near field. Two data reducing processes, sideslip angle correction, and induced velocity correction, were proposed to determine the effective angle of attack based on the inflow data measured by probes. The aerodynamic measurement platform was first validated by the comparison with wind tunnel results. Then some particular aerodynamic phenomenon in the field were discussed. As a result, the angle of attack varies quasi-periodically with the rotation of the rotor, which is caused by the yaw angle of the inflow. The variation of angle of attack induces dynamic response of a clockwise hysteresis loop in lift coefficient. The dynamic response is the main source of a dispersion of instantaneous lift coefficients with a standard deviation of 0.2.

Physical modelling of changes in the energy impact on a worker taking into account high-temperature radiation

Purpose: The purpose of this investigation is development of an experimental installation and definition the intensity of thermal irradiation at workplaces to ensure safety under condition of increased thermal radiation. This purpose is justified as follows. Human health and well-being depend to a large extent on conditions of the internal environment of the premises, which affect the heat exchange of workers with the surrounding surfaces. With this the spectral composition and intensity of irradiation are also important for assessing the effect of thermal radiation. Design/methodology/approach: The investigation was carried out using special experimental device. Uniformly lit semitransparent screen was used as a source of thermal radiation source. We used photo film with heat flow sensor ДТП 02 – ДТП 03 developed by Institute of Engineering Thermophysics under Academy of Science of Ukraine as model of the elementary surface of human body. Findings: Based on results of conducted research and optimization, we propose protective compositors that are nonflammable. This fact allows the increase in safety of facilities during operation and evacuation routes in emergency case due to high-temperature effects. Research limitations/implications: In this study, was focused on the dependence of the local angular coefficient of irradiation and maximum thermal loads, as well as the transition from indirect measurements to direct ones. This allows us to predict working conditions by the thermal factor in the workplace. Practical implications: The results of this study can be recommended to the Ministry of Health and the Ministry of Industry for the development to reduce the incidence of occupational morbidity among workers who work under conditions of exposure of thermal radiation. Originality/value: It was disclosed that it is possible to determine the distance to the source of thermal radiation from the point of measurement and the angle at which the source of thermal radiation is visible with high accuracy. Moreover, measurement point may be located at a distance safe for the researcher.

FILM COOLING OVER A FLAT PLATE WITH COOLANT SUPPLY IN TO TRIANGULAR INDENTATION

The modern high-performance gas turbine engines operate at the flow temperatures exceeding the melting temperature of materials, which require the blade cooling. However, the traditional scheme of film cooling is characterized by appearance of secondary vortex structures that destroy the coolant film. From the existing alternative schemes of film cooling, which allow protecting the turbine blades from influence of high temperatures, the scheme with triangular dimples has demonstrated good results in the stationary conditions. This cooling scheme was patented and tested in the Institute of Engineering Thermophysics, National Academy of Sciences of Ukraine. In order to determine the feasibility of such a scheme, it is necessary to consider the effect of the blade rotation influencing the film cooling efficiency. The results are given towards theoretical investigation of the film cooling efficiency of this scheme under rotation conditions. The study was performed using the ANSYS CFX package using SST-turbulence model. The blowing ratio was varied from 0.5 to 2.0. Numerical simulation performed for rotation parameters corresponding to the dominant influence of the Coriolis force – 10, 100 rpm, and centrifugal forces – 3000, 5000 and 7000 rpm. Оn the basis of computer simulation, it has been shown that rotation does not affect weakly the average efficiency of film cooling at Coriolis force, but causes a peak displacement of local adiabatic efficiency, at rotation parameter of 7000 rpm, when there is a distortion of the flow lines.