scholarly journals COMPONENTS OF MATHEMATICAL MODEL OF TEXTILE YARN EXTENSION TO A BREAK IN TECHNOLOGICAL PROCESSES

2019 ◽  
pp. 14-19
Author(s):  
K. S. Sultanov ◽  
S. I. Ismoilova ◽  
S. E. Tulonov
Keyword(s):  
Mathematical Model ◽  
Mathematical Simulation ◽  
Textile Yarn ◽  
Cotton Yarn ◽  
Motion Velocity ◽  
Strain Modulus ◽  
Technological Processes ◽  
Motion Process ◽  
External Forces ◽  
Nonlinear Elastic

The idea that mathematical simulation of the process of textile yarn stretching which reveals new features of its destruction in technological processes is substantiated in the paper. Mathematical model should take into account textile yarn motion velocity in technological processes, acting external forces, and the reliable law of yarn strain under stretching. Secant moduli of cotton yarn strain were determined from experimental diagrams of cotton yarn stretching. A significant nonlinearity of the change in strain modulus depending on the strain value is shown. An account of this factor leads to physically nonlinear laws of cotton yarn strain. Therefore, as the basis of a mathematical model of the motion process, a physically developed nonlinear elastic-viscoplastic law of cotton yarn strain is proposed. The main properties of the proposed law and the methods for determining its support dependencies are discussed. An algorithm for using the law in a mathematical model of the process of yarn strain to a break is proposed.

scholarly journals Changes in the Uneven Indexes of Sliver and Threads by Different Technological Processes

2020 ◽  
Vol 9 (1) ◽  
pp. 2809-2812
Keyword(s):  
Mechanical Properties ◽  
Quality Indicators ◽  
Technological Process ◽  
Textile Yarn ◽  
Processing Plant ◽  
Cotton Yarn ◽  
Light Industry ◽  
Modern Equipment ◽  
Optimal Variant ◽  
Technological Processes

The article describes information about textile yarn with texture 20.0, which was obtained from the cotton yarn samples in the laboratory of "Spinning Technology" of the Tashkent Institute of Textile and Light Industry at the cotton processing plant in Akkurgan district of Tashkent region. Worked out in three different options, firstly, raw cotton was converted into fiber in the laboratory of the mill, and the quality indicators of the obtained sliver, wick and thread were studied in the modern equipment of the Uster Tester-5 in the Enterprise" Shovot tex", and were also studied the physic-mechanical properties of the threads in the laboratory" CentexUz" and proposed an optimal variant of the technological process for release

Classification of mathematical models of technological design

2021 ◽  
pp. 68-71
Author(s):  
Keyword(s):  
Mathematical Model ◽  
Mathematical Models ◽  
Technological Process ◽  
Process Design ◽  
Geometric Parameters ◽  
Technological Design ◽  
Technological Processes ◽  
Technological Preparation

The use of mathematical models is of great importance for the automation of the design of technological processes. Representation of the geometric parameters of the part in the form of mathematical models allows automating the development of the structure and calculation of the parameters of the technological process, which is important for the complete digitalization of the technological preparation of production. Keywords: technological process, design, mathematical model, digitalization. [email protected]

scholarly journals ON PREVENTIVE MAINTENANCE POLICY FOR WAVE DISSIPATING BLOCKS COVERING CAISSON BREAKWATER

2018 ◽  
pp. 72
Author(s):  
Takao Ota ◽  
Hiroyuki Kawamura ◽  
Yoshiharu Matsumi ◽  
Junji Koyanagi ◽  
Takashi Satow
Keyword(s):  
Mathematical Model ◽  
Preventive Maintenance ◽  
Maintenance Cost ◽  
Maintenance Policy ◽  
Reliability Engineering ◽  
Coastal Structures ◽  
Service Period ◽  
Caisson Breakwater ◽  
External Forces ◽  
Preventive Maintenance Policy

The infrastructures are required to keep a certain level of performance during the duration of service. Because the performance of the infrastructures including harbor and coastal structures deteriorates due to aging and damage that is caused by the action of external forces, it is necessary to perform appropriate maintenance. Satow et al. (2009) proposed a mathematical model for the preventive maintenance of wave dissipating blocks based on the method of the reliability engineering. They also derived the expected maintenance cost over the in service period and the optimal preventive maintenance policy. In this study, the optimal threshold for preventive maintenance to minimize the expected maintenance cost is determined for the wave dissipating blocks covering caisson breakwater by using the above model.

scholarly journals Belt conveyor failure simulation at the design stage with transverse displacements of the belt

2020 ◽  
Vol 168 ◽  
pp. 00056
Author(s):  
Vitalii Monastyrskyi ◽  
Serhii Monastyrskyi ◽  
Denis Nomerovskyi ◽  
Borys Mostovyi
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Fourier Transform ◽  
Adaptive Control ◽  
Design Stage ◽  
Belt Conveyor ◽  
Failure Simulation ◽  
The Fourier Transform ◽  
External Forces ◽  
The Mathematical Model

To find possible conveyor failures at the design stage means to determine a transverse belt displacement and compare the obtained data with the permissible ones. The dynamic problem of the belt movement on the conveyor has been defined. Resistance and external forces, limits of the belt displacement have been determined. The transverse belt displacement can be described by partial differential equations. To solve the problem, the Fourier transform has been used. Change patterns in the transverse belt conveyor displacement dependent on conveyor’s parameters, type of load, and skewing of the idlers along the conveyor have been obtained. The results agree with experimental data. The method of adaptive control of the transverse belt displacement has been described. The essence of this method is to adapt the model of the moving belt in the conveying trough to changed conditions and to reveal the uncertainty of the control with the known parameters of the mathematical model.

Mathematical Simulation of Hydraulic Power Pulse Machine at Matlab

2016 ◽  
Vol 685 ◽  
pp. 240-243 ◽  
Author(s):  
M.V. Novoseltseva ◽  
E.N. Pashkov ◽  
I.A. Masson
Keyword(s):  
Mathematical Model ◽  
Mathematical Simulation ◽  
Model Simulation ◽  
General Idea ◽  
Restriction Factors ◽  
Hydraulic Power ◽  
Power Pulse ◽  
Machine Operation ◽  
Simulation Results

General idea of mathematical simulation is set. Equations that describe hydraulic power pulse machine operation are described. Restriction factors are identified; they are included in mathematical model simulation. Mathematical simulation results are shown for essential parts of machine. Results of hydraulic power pulse machine mathematical simulation are presented.

Analytical Upper Limit of Drag Reduction With Polymer Additives in Turbulent Pipe Flow

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Xin Zhang ◽  
Xili Duan ◽  
Yuri Muzychka
Keyword(s):  
Mathematical Model ◽  
Drag Reduction ◽  
Pipe Flow ◽  
Critical Concentration ◽  
Turbulent Pipe Flow ◽  
Chemical Additives ◽  
Upper Limit ◽  
Maximum Drag Reduction ◽  
Flow Drag ◽  
Nonlinear Elastic

Flow drag reduction induced by chemical additives, more commonly called drag-reducing agents (DRAs), has been studied for many years, but few studies can manifest the mechanism of this phenomenon. In this paper, a new mathematical model is proposed to predict the upper limit of drag reduction with polymer DRAs in a turbulent pipe flow. The model is based on the classic finitely extensible nonlinear elastic-Peterlin (FENE-P) theory, with the assumption that all vortex structures disappear in the turbulent flow, i.e., complete laminarization is achieved. With this model, the maximum drag reduction by a DRA at a given concentration can be predicted directly with several parameters, i.e., bulk velocity of the fluid, pipe size, and relaxation time of the DRA. Besides, this model indicates that both viscosity and elasticity contribute to the drag reduction: before a critical concentration, both viscosity and elasticity affect the drag reduction positively; after this critical concentration, elasticity still works as before but viscosity affects drag reduction negatively. This study also proposes a correlation format between drag reduction measured in a rheometer and that estimated in a pipeline. This provides a convenient way of pipeline drag reduction estimation with viscosity and modulus of the fluids that can be easily measured in a rheometer.

scholarly journals Mathematical simulation of hard excitation of cavitation self-oscillations in a liquid-propellant rocket engine feed system

2021 ◽  
Vol 2021 (1) ◽  
pp. 29-36
Author(s):  
S.I. Dolgopolov ◽  
Keyword(s):  
Mathematical Model ◽  
Mathematical Simulation ◽  
Small Amplitude ◽  
External Disturbance ◽  
Liquid Propellant ◽  
Feed System ◽  
Hard Excitation ◽  
Set Up ◽  
Pump Inlet ◽  
Propellant Rocket

Hard self-oscillation excitation differs from soft excitation in that self-oscillations are set up only if the initial departure of an oscillating system from equilibrium is strong enough. Experimental studies of cavitation oscillations in hydraulic systems with cavitating pumps of liquid-propellant rocket engines ((LPREs) include works that describe hard excitation of cavitation oscillations. By mow, hard excitation regimes have not been explained theoretically, to let alone their mathematical simulation. This paper presents a mathematical model of hard excitation of cavitation oscillations in a LPRE feed system, which comprises a mathematical model of cavitation self-oscillations in a LPRE feed system that accounts for pump choking and an external disturbance model. A mechanism of hard excitation of cavitation oscillations in a LPRE feed system is proposed. It is well known that hard excitation of cavitation self-oscillations may take place in cases where the pump feed system is near the boundary of the cavitation self-oscillation region. In this case, the self-oscillation amplitudes are small, and they are limited only by one nonlinearity (cavity volume vs. pump inlet pressure and flow relationship). Under excitation of sufficient intensity, the pump inlet pressure and flow find themselves in the choking characteristic; this may be responsible for choking and developed cavitation self-oscillations, which remain of interrupted type and do not go into the initial small-amplitude oscillations even after excitation removal. A mathematical simulation of hard excitation of cavitation self-oscillations was conducted to determine the parameters of cavitation self-oscillations in a bench feed system of a test pump. The simulation results show that without an external disturbance the pump system exhibits small-amplitude self-oscillations. On an external disturbance, developed (interrupted) cavitation oscillations are set up in the system, which is in agreement with experimental data. The proposed mathematical model of hard excitation of cavitation self-oscillations in a LPRE feed system allows one to simulate a case observed in an experiment in which it was possible to eliminate cavitation self-oscillations by an external disturbance.

scholarly journals Building a mathematical model of technological processes in the acetic acid synthesis reactor

2021 ◽  
Vol 5 (2 (113)) ◽  
pp. 94-104
Author(s):  
Zhanna Samojlova
Keyword(s):  
Mathematical Model ◽  
Acetic Acid ◽  
Acid Synthesis ◽  
Critical Value ◽  
Reaction Mass ◽  
Stationary Mode ◽  
Fisher Criterion ◽  
Technological Processes ◽  
Level Of Significance ◽  
The Mathematical Model

The result of the study reported in this paper is the proposed mathematical model of technological processes occurring in the reactor for acetic acid synthesis. The initial parameters of the reactor considered were the value of the concentration of acetic acid at the reactor outlet, temperature, the level of reaction mass, and pressure in the reactor. The input parameters included the amount of methanol and carbon monoxide supplied. Material and thermal balances of reactor technological processes were used to construct the mathematical model of the reactor. Fisher criterion was applied to test the mathematical model for adequacy. At the specified 5 % level of significance, the value of Fisher criterion for the concentration of acetic acid, temperature, and the level of reaction mass in the reactor does not exceed its critical value for a stationary mode. The reproducibility of the modeling results was tested using the Cochran criterion. The value of the Cochrane criterion, at the predefined 5 % level of significance, for the concentration of acetic acid, temperature, and the level of reaction mass in the reactor does not exceed its critical value for different modes. The relative error for the modeled output parameters was calculated. The relative error of the initial parameters did not exceed the level of 10 %. The model built makes it possible to calculate with satisfactory accuracy the value of the concentration of acetic acid at the reactor output, the temperature and level of the reaction mass in the reactor under a stationary mode. The resulting model could be used to automate the control of technological processes in the acetic acid synthesis reactor under a stationary mode. The study results open additional opportunities to manage the stationary mode of the reactor

Sign in / Sign up

Export Citation Format

Share Document