Dynamics of Working Processes in Automatic Direct-Acting Pressure Regulators of Pneumatic Spacecraft Systems

2021 ◽  
pp. 65-76
Author(s):  
A.V. Lebedev ◽  
A.V. Chernyshev ◽  
Y.V. Kyurdzhiev ◽  
A.P. Mitrofanov ◽  
O.S. Ilicheva ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Software Package ◽  
Block Diagram ◽  
Working Fluid ◽  
Pressure Regulator ◽  
Conservation Of Energy ◽  
General Mathematical Model ◽  
Direct Acting ◽  
The Mathematical Model ◽  
Working Processes

The purpose of the study was by means of modern software to explore working processes taking place in automatic direct-acting pressure regulators of pneumatic spacecraft systems. As a result, we developed a general mathematical model of the pressure regulator. The design of the regulator is shown in the form of a block diagram, composed of a set of channels, cavities, and stages. The elements of the block diagram are interconnected by the basic laws of conservation of energy and mass. The mathematical model was evaluated in the Amesim software package. Findings of the full-scale and computational experiments led to the conclusions about the effect the heat exchange between the working fluid and the environment produces on the parameters of the pressure regulator, and about the use of the Amesim software package for further research of working processes in the valve units of pneumatic systems.

scholarly journals МАТЕМАТИЧЕСКОЕ МОДЕЛИРОВАНИЕ ЭЛЕКТРОНАГРЕВНОЙ ДВИГАТЕЛЬНОЙ УСТАНОВКИ В ФОРМИРОВАНИИ МИКРОСПУТНИКОВОЙ ГРУППИРОВКИ

2018 ◽  
pp. 45-51
Author(s):  
Андрей Владимирович Погудин
Keyword(s):  
Mathematical Model ◽  
Transfer Functions ◽  
Block Diagram ◽  
Rocket Engine ◽  
Control Unit ◽  
Electric Heating ◽  
Propulsion System ◽  
Working Fluid ◽  
Space Vehicles ◽  
The Mathematical Model

The subject of the study in the article is the mathematical model of the propulsion system. It is built on the basis of the formed transfer functions of the elements. The goal is to rationalize the process of heating the onboard propulsion system on the basis of mathematical model under given constraints. Tasks: formalization of processes in an electric heating engine with a working body ammonia; formalization of the model of the onboard propulsion system; formation of the structural scheme; consideration of physical processes occurring in the nodes of the propulsion system; description of gas and hydraulic processes; the description of thermodynamic and electrokinetic processes; The construction of a mathematical model based on transfer functions. The methods used are: models of transfer functions of a tank, a filter, a steam generator, a receiver and a jet, an engine with their ranges of work. The following results are obtained. A block diagram of the onboard propulsion system was added, supplemented with a control unit and a power supply system. A formalized mathematical model of an onboard propulsion system with working body ammonia is created. From it formed a model consisting of the key elements that make up the onboard propulsion system, which is used when rationalizing the heating of the working fluid. The scientific novelty of the results is as follows. The mathematical model of the electro-heating propulsion system onboard small space vehicles has been further developed through its application to calculate the traction characteristics of the dispenser, which makes it possible to use an ammonia electric heating rocket engine in the formation of a constellation of satellites. The limitations of the operating parameters of the model are introduced. It was proposed to conduct the further workability of the model in Matlab Simulink. Thus, a rational value of the current and voltage parameters will be obtained, at which the time of the system's output to the operating mode will be minimal, and the thrust is maximum for the given operating temperature and pressure ranges

Performance Analysis of a Solar-Assisted Organic Rankine Cycle

2020 ◽  
Author(s):  
M. T. Nitsas ◽  
I. P. Koronaki
Keyword(s):  
Mathematical Model ◽  
Performance Analysis ◽  
Temporal Variation ◽  
Storage Tank ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Evaporation Temperature ◽  
Solar Powered ◽  
The Mathematical Model

Abstract The objective of this paper is the thermodynamic analysis of a solar powered Organic Rankine Cycle (O.R.C.) and the investigation of potential working fluids in order to select the optimum one. A dynamic model for a solar O.R.C. with a storage tank, which produces electricity is developed. The mathematical model includes all the equations that describe the operation of the solar collectors, the storage tank, the Rankine Cycle and the feedback between them. The model runs for representative days throughout the year, calculating the net produced energy as a function of the selected evaporation temperature for every suitable working fluid. Above that, the temporal variation of the systems’ temperatures, collectors’ efficiency and net produced power, for the optimum organic fluid and evaporation temperature are presented.

Mathematical Model of Three-Phase Boost Converter

2012 ◽  
Vol 507 ◽  
pp. 96-100
Author(s):  
Zhong Zhang ◽  
Wei Ming Tong
Keyword(s):  
Mathematical Model ◽  
Nonlinear Control ◽  
Control Strategy ◽  
Boost Converter ◽  
Analysis Method ◽  
Topology Structure ◽  
Conservation Of Energy ◽  
Three Phase ◽  
Converter Topology ◽  
The Mathematical Model

Now the nonlinear control strategy used by a lot of power electronic converters is not dependent on the mathematical model of the system. They are only based on the error of control variables to control the output voltage or other variables, and this leads to the shortcomings of poor control and not easy to optimize. The fundamental reason is that they are not based on the mathematical model of converter topology structure. This paper presents a new way to build mathematical model. The paper established the unified mathematical model of the three-phase Boost converter topology structure by studied the three-phase Boost converter topology structure deeply and based on the law of conservation of energy and combined with small-signal modeling analysis method, and done the systematic analysis for it. The analysis method is also applicable to other converter topology, such as the buck, buck-boost, etc., and the model not only can be used in the controller design, can also provide a theoretical basis for the applications of a new nonlinear control strategy.

Stability of Velocity-Loop-Based Hydraulic Control Loading System

2012 ◽  
Vol 619 ◽  
pp. 472-475
Author(s):  
Pan Guo Qi ◽  
Li Wei Zhao ◽  
Pei Chao Cong ◽  
Hui Wang
Keyword(s):  
Mathematical Model ◽  
Block Diagram ◽  
System Model ◽  
Flight Simulator ◽  
Stability Conditions ◽  
Hydraulic Control ◽  
Function Block ◽  
Loading System ◽  
The Stability ◽  
The Mathematical Model

A hydraulic Control Loading System (CLS) based on velocity-loop was developed and installed on our flight simulator earlier days, but the CLS cannot keep stable in some conditions. This problem is discussed in this paper. The mathematical model of velocity-loop-based CLS is firstly developed with the method of transfer function block diagram. Then, system’s stability conditions are put forward using Roth criterion based on the system model developed. At last, the experiments proves the stability

NUMERICAL AND PROGRAM IMPLEMENTATION OF A ONE-DIMENSIONAL MATHEMATICAL MODEL OF HYDRAULIC FRACTURING

2021 ◽  
Vol 7 (1) ◽  
pp. 126-145
Author(s):  
Alexey S. SHLYAPKIN ◽  
Alexey V. TATOSOV
Keyword(s):  
Mathematical Model ◽  
Hydraulic Fracturing ◽  
Program Implementation ◽  
Software Package ◽  
Import Substitution ◽  
Point Of View ◽  
Growth Potential ◽  
Design Problems ◽  
Software Market ◽  
The Mathematical Model

At present, an active policy of import substitution is being pursued, dictated by the imposed international sanctions, which creates a need for finding optimal engineering solutions, in particular, in the field of creating Russian software. In the study and design of hydraulic fracturing, they often rely on the results of modeling in specialized simulators. The appearance of the Russian products on the software market, surely, sets the correct vector of development; however, some aspects are not implemented in the existing mathematical models. The authors of this article present a model that allows considering in detail the process of movement of proppant particles in a hydraulic fracture. The chosen direction is important from the point of view of calculating the fracture cavity and refining its productivity, since the behavior of the particles has a significant effect on both the growth potential of the crack and its shape. The research methodology includes a theoretical justification of the mathematical model presented by the authors in their previous works; a description of the basic principles of selecting and constructing a numerical calculation scheme and creating a software package. The main methods of research are the methods of mathematical modeling, formed from practical problems on the estimation of geometric parameters of the crack, including the areas of continuum mechanics and fracture of solids, underground hydrodynamics. The proposed and implemented numerically mathematical model forms the basis of the authors’ software package, which allows solving the main design problems when performing hydraulic fracturing operations.

Influence of pressure distribution in the gap of piston-cylinder unit and properties of working fluid PES-3 on characteristics of high pressure piston-cylinder unit

2020 ◽  
pp. 38-42
Author(s):  
A. E. Aslanyan
Keyword(s):  
Mathematical Model ◽  
High Pressure ◽  
Pressure Distribution ◽  
Pressure Range ◽  
Pressure Change ◽  
Working Fluid ◽  
Research Results ◽  
Piston Cylinder ◽  
Pressure Distributions ◽  
The Mathematical Model

A simulation of the use of PES-3 liquid in a high-pressure piston-cylinder units was performed, and the parameters of the piston-cylinder units were determined in the article. The equations of the mathematical model describing the pressure change in the gap between the piston and the cylinder are given. As a result of the calculations, the pressure distributions in the gap between the piston and the cylinder are determined at under piston pressures less than 1.6 GPa. The profiles of the gaps between the deformed piston and cylinder at different under piston pressures are calculated. The dependences of the speed of lowering the piston and the effective gap on the under piston pressure at different gaps of the undeformed piston-cylinder unit are obtained. The research results can be used in the design of piston cylinder units operating on PES-3 liquid in the pressure range of 0.01–1.6 GPa.

TECHNIQUE OF APPLICATION FOR PROCESSING OF LOW PASS FILTER LF SIGNALS

10.12737/7905 ◽  
2015 ◽  
Vol 7 (4) ◽  
pp. 35-38
Author(s):  
Табаков ◽  
Yu. Tabakov ◽  
Лавлинский ◽  
V. Lavlinskiy
Keyword(s):  
Mathematical Model ◽  
Block Diagram ◽  
Low Frequency ◽  
Frequency Signal ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
The Mathematical Model ◽  
40 Hz

The article includes a block diagram and the mathematical model for low pass filter designed for processing low frequency signal with a frequency of 10-40 Hz in order of eliminate various noises and interference.

Mathematical Modeling and Optimization of Fluidized Layer Carbonitriding Process for 1C 25 Steel

2017 ◽  
Vol 1143 ◽  
pp. 180-187
Author(s):  
Marian Iulian Neacsu ◽  
Sorin Dobrovici
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Software Package ◽  
Order Equation ◽  
Graphical Interface ◽  
Technological Parameters ◽  
Fluidized Layer ◽  
The Mathematical Model ◽  
Hardness Values ◽  
Temperature Depth

This paper presents the experiment-based mathematical modelling of fluidized bed carbonitriding process for 1C 25 steel meant to optimize this type of thermochemical processing.Based on experimental results, the mathematical model was developed, which is a second order equation with three unknown terms (parameters): temperature, depth of carbonitrided layer, the percentage of ammonia.The mathematical model allowed the simulation of the fluidized layer carbonitriding process according to its parameters and the thermal energy optimization for obtaining HV hardness values in the range 300-400 MPa.Using the software package Matlab a graphical interface was done, through which all the combinations of technological parameters of the carbonitriding process are determined, leading to obtaining values of microhardness between 300 and 400 MPa, as well as the amount of energy consumed for each variant. The variant consuming the lowest energy is considered optimal.

Experimental and Theoretic Research on Solar Power Membrane Distillation

2010 ◽  
Vol 97-101 ◽  
pp. 2300-2305
Author(s):  
Hong Jiang Cui ◽  
Pei Ting Sun ◽  
Ming Hai Li
Keyword(s):  
Mathematical Model ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Efficiency ◽  
Solar Power ◽  
Membrane Distillation ◽  
Working Fluid ◽  
Air Gap Membrane Distillation ◽  
The Mathematical Model

Air gap membrane distillation experiments of different temperature and mass flow rate of working fluid were done for the use of solar power and setting up the mathematical model of AGMD’ heat and mass transfer. The calculation correctness of mathematical model was discussed and the thermal efficiency of membrane distillation system was calculated. The results showed that the experimental flux of membrane distillation reached 49kg/m2•h and the biggest relative error is less than 9% between results of experiment and mathematical model calculation. The mathematical model can be used to forecast the process parameters of membrane distillation. The highest thermal efficiency of this system is 68% and the main influencing factors of thermal efficiency are temperature and mass flow rate of working fluid.

General Mathematical Model of Internal Meshing Spiral Bevel Gears for Nutation Drive

2011 ◽  
Vol 101-102 ◽  
pp. 708-712 ◽  
Author(s):  
Zheng Lin ◽  
Li Gang Yao
Keyword(s):  
Mathematical Model ◽  
3D Modeling ◽  
Gear Tooth ◽  
Spiral Bevel Gears ◽  
Bevel Gears ◽  
General Mathematical Model ◽  
Spiral Bevel ◽  
The Mathematical Model ◽  
Crown Gear ◽  
Internal Meshing

The general mathematical model of internal meshing spiral bevel gears for nutation drive is studied. Based on conventional enveloping theory and transmission principle, the meshing of two spiral bevel gears in nutation drive was substituted by the meshing of an imaginary rotating crown gear engaging with the external and internal bevel gear respectively. The general mathematical model of crown gear was established. Then the general mathematical model of internal meshing spiral bevel gears is obtained by matrix transformation, which is suitable for a variety of gear tooth profiles. Finally, the mathematical model and 3D modeling of double circular-arc spiral bevel gears are developed.

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