Vol 15, No 1 (2021)
Articles
Vibration levels on operator’s workplace and vibration protection characteristics of seat suspensions
Abstract
Improving the efficiency and safety of operation of underground tunnel escalators. Forecasting model
Abstract
Calculation of wind turbine generator power characteristics using Windpowerlib software module
Abstract
The problem of using alternative energy sources is becoming more and more urgent every year. Wind turbogenerators are one of the most promising alternative power plants. The article is devoted to the creation and testing of a calculation program for determining the main indicators of wind generators - the dependence of the power factor (efficiency) and the generated power on wind speed, the power change curve by time intervals, and the average power per year. At the beginning of the work, basic information is given about alternative power plants, in particular, about wind generators, their advantages, disadvantages and methods of feasibility study for use in a given area according to weather statistics. The following are the modules used in the program, the main of which is a special command library for calculating wind turbines Windpowerlib. The sequence of implementation of the calculation algorithm stages is described: methods of entering weather data and the main characteristics of the turbine, the procedure for calculating the power of the turbine generator, and the output of results in the form of qualitatively formalized graphs. To test the developed program, the energy characteristics of one of the most common and widely used wind generators in the world were calculated - the Siemens SWT 3.6-120 model, the calculation results were compared with operational data published by the manufacturer of this plant. The graphs proved a high degree of conformity between the calculated and actual characteristics. The plant capacity change during the year is determined by hourly time intervals, as well as the average capacity generated per year. The resulting software product allows the end user to easily download input data and automatically calculate all the above characteristics of any wind turbine. In conclusion, conclusions were drawn on the work done, recommendations were made to expand the scope of the methodology to determine the characteristics of other power plants. The planned direction of further research in this area using the developed software product is indicated.
Calculation of the coefficient of local hydraulic diaphragm resistance in transitional and laminar areas of flow
Abstract
Method for determining the temperature fields of the spark plug
Abstract
This article examines the main factors that determine the thermal performance of a spark plug in the temperature range from 300 to 2500 Kelvin. The optimal value of the temperature of the heat cone was determined. A technique and algorithms for the numerical simulation of the thermal state of a spark plug are presented. These made it possible to calculate the dependence of the thermal conductivity coefficient of ceramic elements of a plug and the specific heat capacity of ceramic insulator on temperature. The calculation of the working cycle in the engine cylinder was carried out. The calculation of the temperature distribution of heat fluxes in the elements of the spark plug design was performed.
The assessment of the thermal characteristics of the spark plug is carried out by the method of numerical modeling of the operating cycle of an internal combustion engine. The calculation of the instantaneous temperature distribution in the body of the spark plug and on its surface is carried out. Calculations of the intensity of heat fluxes between the spark plugs and adjacent parts of the working fluid were carried out.
The modeling of the operating cycle for various operating modes of the engine was made. The temperature fields of the spark plugs were determined. An array of initial data for calculating the temperature fields of the spark plug was formed. Dependences of the temperature of the working fluid in the vicinity of the spark plug on the angle of rotation of the crankshaft are determined. The harmonic components of the heat transfer coefficients between the working fluid and the cylinder fire guard (Voshni coefficient) are considered. The harmonic components of the heat flux density are considered. Calculations of the heat field of the spark plug are carried out for various operating modes of the engine, using the finite element method. The calculation of the temperature field of the spark plug by the finite element method was carried out using ANSYS, SolidWorks, Inventor, etc.
Numerical simulation of dynamic processes in transmission of vehicle
Abstract
The article considers the issues of digital modeling of dynamic processes in the transmissions of transport vehicles. The purpose of this research was to develop an algorithm for numerical mathematical modeling of dynamic processes in the transmissions of transport vehicles using modern digital software packages. The method includes a systematic approach to the study of dynamic processes during switching, based on modeling the operation of the gearbox together with the internal combustion engine (taking into account its dynamic, speed and load characteristics). The order of application of the MATLab – Simulink, Simscape software packages for numerical simulation of dynamic processes is considered. Using the fundamental blocks of these applications, models of physical components are created: the internal combustion engine, friction clutches, gearboxes, elastic shafts, damping devices, and tractor power transmission control systems. A digital model of the tractor transmission is created, its design scheme is given, and the initial characteristics are set. It was used to simulate dynamic processes in the tractor gearbox. The main attention in this paper is paid to the application of the proposed method for calculating the dynamic processes in the gearbox during gear changes under load with forward and reverse switching, including the simultaneous use of several friction clutches.