Energy and exergy analysis of a downstream single-row air washer at different droplet diameters for air cooling application

This study proposes a downstream single-row air washer for air cooling. The theoretical energy and exergy balance models were established at different droplet diameters and verified by the experimental data. Based on the abovementioned theoretical relationship, the single performance indicator of heat exchange efficiency (HEE) and exergy efficiency was quantitatively analyzed; a comprehensive analysis method of two indicators was proposed, combining HEE and exergy efficiency, and a numerical simulation was carried out. Results show that the smaller the droplet diameter and the larger the water–air ratio, the lower the dry-bulb temperature of the outlet air and the higher the HEE and exergy flux destruction. When the droplet diameter is less than 440 μm, the droplet diameter does not affect exergy efficiency and dry-bulb temperature. When the droplet diameter is larger than 440 μm, the droplet diameter is positively correlated with the air outlet dry-bulb temperature and exergy efficiency; in contrast, the water–gas ratio is negatively correlated with the air outlet dry-bulb temperature. An engineering case reveals that when the air outlet temperature is less than 34°C, the critical water–gas ratio can be set as 2.6 (mass ratio). At this time, the HEE is more than 90%, the exergy efficiency is more than 60%, and the critical value of droplet diameter is 440 μm. The research results provide an essential theoretical basis for the optimization of engineering design calculation.

Development of methodology and measures to ensure the reliability of energy systems equipment

THE PURPOSE: The article presents the results of the development of a methodology for the design calculation of reliability and changes in the level of reliability of energy systems, taking into account the influence of control actions based on statistical methods of collection, analysis and models of experimental data processing.METHODS: The system analysis and generalization of experimental data on technological failures of the main equipment of thermal power plants were used in the calculation assessment.RESULTS: The objective function of controlling the reliability parameters of the thermal power plant power equipment is proposed. The approbation of the presented objective control function was performed, which showed the adequacy of the results obtained to assess the reliability of the main nodes and elements of the TPP power equipment.CONCLUSION: The results of the conducted studies show that when determining reliability indicators, it is necessary to take into account the actual technical condition of individual elements and resource-determining functional units of thermal power plant power equipment. The results obtained can be used to develop a methodology for evaluating control actions for calculating the output control parameters and a mathematical model for changing the output characteristics of TPP steam turbines in terms of heat and electric energy generation, as well as at the stage of developing design documentation for the creation of structural elements and practical recommendations in order to extend the service life of power equipment generating systems based on digital technologies.

Designing and Modeling of a Municipal Wastewater Treatment Plant With GPS-X

Wastewater treatment is the process used to remove contaminants from wastewater to produce an effluent suitable for discharge to the environment. Several kinds of wastewater are treated based on the concentration of various parameters. Domestic Wastewater/Municipal Wastewater is treated in Sewage Treatment Plants (STP), which involve various types of processes like physical, chemical and biological to treat the wastewater better. The treatment plant involves five steps of the process – preliminary treatment, primary treatment, secondary treatment, tertiary treatment and sludge treatment to meet the safe disposal guidelines of the department of the environment. In this paper, a municipal wastewater treatment plant for Uttara City is designed and modeled with GPS-X. GPS-X is a wastewater treatment plant modeling software package that is used for verify the treatment process. The design calculation of all unit operations is shown with a specification table. The Process Flow Diagram (PFD), Process Block Diagram (PBD) and mass balance of the process are expressed in the article. The design calculation of the STP is performed with a steady-state process. After each unit operation, the concentration of various parameters – TSS, BOD, VSS, TN is analyzed and the removal efficiency for different equipment is calculated. The STP is designed to maintain the guidelines of the Department of Environment, Bangladesh. At the end of the paper, the designing and modeling steps of a sewage treatment plant will be pursued. Finally, some recommendations are done in the conclusion section.

Experimental Investigation on the Pressure Distribution Law and Calculation Method of Muddy Water with High Silt Content

The pressure distribution law of muddy water with high silt content has great influence on the stress and strain calculation of the dam body. Currently, there is a few research studies referring to the calculation method of high silt content muddy water pressure, which leads to no reliable theoretical basis for muddy water pressure calculation in dam design. In this paper, muddy water with high silt content was prepared and the imitation tests and model tests were carried out to investigate the pressure distribution law. Based on the test result analysis, it is indicated that the muddy water with high silt content is also in a flowable and viscous state, which is consistent with the law of fluid behavior; the horizontal pressure is equal to the vertical pressure at the same position, and this relationship is generally time independent; through the test result analysis, a pressure formula for muddy water with high silt content is proposed; through comparison between the pressure formula-calculated results and monitoring data, it is indicated that the proposed pressure formula is applicable in the calculation of muddy water pressure. The formula can be a useful tool in the dam safety and design calculation.

Selection of the Design of a Contact Condenser of a Gas-Steam Plant with Steam Injection into the Combustion Chamber

Due to the importance of the problems of implementing energy-saving technologies in modern conditions, one of the promising areas is the use of gas turbines for combined heat and power generation. One of the areas of effective development and technical re-equipment is the widespread use of highly economical combined steam and gas plants and gas turbines. The operation of the gas turbine unit “Aquarius” SE NPCG “Zorya-Mashproekt” with the injection of steam into the combustion chamber, which operates on the advanced cycle A-STIG and has in its circuit equipment for water regeneration, condensed from a vapor-gas mixture is considered. For condensation of steam from the vapor-gas mixture, a contact condenser-gas cooler is used, which is a mixing heat exchanger of complex design. The efficiency of heat transfer is determined by the design of the nozzle, namely, the developed heat transfer surface, small hydraulic supports, high heat transfer coefficients. An important aspect is the overall dimensions, which must be within certain limits. In the work it is offered to execute a design of the condenser in the form of a packed column. Different types of nozzles are considered to choose the best option. As a result of thermal design calculation of the contact capacitor, it is proposed to use Rashiga rings (15152) as a nozzle, which provide the lowest height of the nozzle at the required diameter of the device.

Tree shaping catalogs: formation and nature of garden chair applications

Purpose: Tree shaping catalog development of practical use: garden chair category; study of the ergonomic aspects of their design, calculation of the time for the formation of tree shaping objects with regard to the plant types. A deeper study of the formation of natural and artistic objects of architectural space, i.e., tree shaping.Design/methodology/approach: Ergonomic analysis, analysis of woody plants compositions in tree shaping, visual-anthropometric analysis, modeling, comparative analysis.Originality/value: 1. Proposed tree shaping catalogs in the category of garden chairs. These catalogs have no analogues in are Russia. 2. The selected woody plants of the West Siberian region, most adapted to humane correction of growth, with the ecological specification in accordance with the following parameters: gas resistance, growth rate, life cycle of a woody plant. 3. Diagrams are suggested for the garden chair dimensions (chair back height, seat width, chair leg height) depending on the woody plant (willow, Tatar maple, bird cherry).Findings: Many identified aspects are can be used in tree shaping: compositional complexity of tree shaping, woody plant type, growth characteristics, and the growing conditions.Practical implications: The obtained results can be used as in a deeper study of new approaches to the formation of open architectural spaces with plant materials.

Crack resistance of masonry walls

Computer models used in the design calculation of masonry buildings sometimes fail to correctly take into account the stress-strain state of walls and assess the likelihood of cracks caused by the deformation differences of interacting walls.Following the construction of a building, cracks can develop at wall intersections for several years. However, their repair is mostly ineffective until the total damping of masonry creep deformation.Drawing on the analysis of conducted research and field data, the authors give recommendations on ensuring the crack resistance of internal masonry walls.

WHY YACHT RUDDERS BREAK

For most sailing yachts, losing a rudder is probably the most catastrophic structural failure other than losing the keel. Rudder failure happens with distressing regularity. This paper examines the hypothesis that the underlying reason is design failure. There are many qualitative decisions to be taken in the design calculation process. Example calculations are presented which show that the maximum rudder force generated in steady state conditions is easily underestimated. For a typical spade rudder of a typical modern production sailing yacht, the normal rudder force should be calculated using a boat speed of at least 125% hull speed, and a force coefficient of at least 1.3. Care must be taken in selecting an appropriate value for the allowable stress of the material used for the stock.

Designing of ship shafts made of polymer composite materials

В работе предложены процедуры для выполнения проектировочного расчета судовых валов из полимерных композиционных материалов. Рассматривалась цилиндрическая оболочка, являющаяся основным телом промежуточного судового вала. Она сформирована из пакетов монослоев, состоящих из армирующего волокна и связующей матрицы. Определяющей нагрузкой на судовой вал принят крутящий момент. Заданы ограничения на параметры напряженно-деформированного состояния, характеризующие формы отказов для оболочки в целом и пакета монослоев. Получены аналитические зависимости, связывающие параметры проектирования с крутильной жесткостью, касательными напряжениями потери устойчивости оболочки и нормальными напряжения в волокне. При заданных характеристиках материала проектирование сведено к определению радиуса и толщины оболочки вала. Выполнена серия проектировочных расчетов, различающихся типом активных ограничений. Полученные варианты проектирования проанализированы с помощью метода конечных элементов. Произведена проверка удовлетворения всех ограничений. Предложены условия проектирования, обеспечивающие приемлемые варианты проектов валов из ПКМ. The paper proposes procedures for performing the design calculation of ship shafts made of polymer composite materials. The cylindrical shell, which is the main body of the intermediate ship shaft, was considered. It is formed from packages of monolayers consisting of a reinforcing fiber and a binding matrix. The determining load on the ship's shaft is assumed to be the torque. Restrictions are set on the parameters of the stress-strain state that characterize the failure forms for the shell as a whole and the monolayer package. Analytical dependences linking the design parameters with torsional stiffness, tangential stresses of the shell loss of stability and normal stresses in the fiber are obtained. With the specified material characteristics, the design is reduced to determining the radius and thickness of the shaft shell. A series of design calculations, differing in the type of active constraints, has been performed. The obtained design options are analyzed using the finite element method. The check of satisfaction of all restrictions is made. The design conditions that provide acceptable variants of shaft designs from PCM are proposed.