MODELING THE HYDRAULIC CHARACTERISTICS OF DRAIN VALVE AND BURST FITTING OF AN AIRCRAFT ACCIDENT-RESISTANT FUEL SYSTEM

2020 ◽  
Vol 7 (3) ◽  
pp. 37-44
Author(s):  
KONSTANTIN NAPREENKO ◽  
◽  
ROMAN SAVELEV ◽  
ALEKSEY TROFIMOV ◽  
ANNA LAMTYUGINA ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Hydraulic Resistance ◽  
Hydraulic Calculation ◽  
Fuel System ◽  
Hydraulic Characteristics ◽  
System A ◽  
Ansys Cfx ◽  
Calculation Results ◽  
Scale Experiment ◽  
Aircraft Accident

The article discusses methods for determining the hydraulic resistance of units of an accident-resistant fuel system. A detailed description of the need to create such fuel systems for modern helicopters is given. The development of such systems today is impossible without the use of the method of mathematical modeling, which allows to qualitatively solve problems arising in the design process. To obtain accurate research results, it is necessary to have a complete description of all elements and assemblies of the system. Methods for determining the hydraulic characteristics of AFS elements using the drag coefficient, reference literature and CFD codes are considered. As the investigated AFS units, a drain valve and burst fitting were studied in the article. A hydraulic calculation of these AFS elements ware performed, the simulation results are presented in the ANSYS CFX software package. Also as the calculation results of bursting fitting, the pressure distribution fields of full and static pressure, velocity and streamlines are also shown. An experimental setup for validating the results obtained using the mathematical modeling method is considered, as well as a methodology for conducting a full-scale experiment to determine the hydraulic resistance of the unit. Materials have been prepared for inclusion in a one-dimensional mathematical model of an accident-resistant fuel system.

Q-H characteristics for heavy crude oil pipeline

2021 ◽  
pp. 32-39
Author(s):  
Сергей Евгеньевич Кутуков ◽  
Ольга Витальевна Четверткова ◽  
Андрей Иванович Гольянов
Keyword(s):  
Detection System ◽  
Hydraulic Calculation ◽  
Pipeline System ◽  
Hydraulic Characteristics ◽  
Oil Pipeline ◽  
Oil Pipelines ◽  
Oil Flow ◽  
Direct Interpretation ◽  
Calculation Results ◽  
Oil Blend

Проблема повышения точности технологических расчетов нефтепроводов обрела особую остроту на фоне модернизации системы обнаружения утечек и разработки программного обеспечения в области планирования грузопотоков в системе магистральных трубопроводов. Расхождение результатов гидравлических расчетов и фактических параметров перекачки вызвано, в частности, такими факторами, как игнорирование мультифазного характера течения нефти (особенно на недогруженных участках нефтепроводов, проложенных по пересеченной местности), отсутствие актуальных данных по состоянию длительно эксплуатируемых труб, применение методик расчета потерь энергии на трение, базирующихся на постулатах классической гидравлики. В настоящей статье авторами предложен метод определения гидравлической характеристики трубопровода на установившемся режиме эксплуатации, перекачивающего неньютоновские реологически сложные нефти в диапазоне малых скоростей сдвига, который предполагает непосредственную интерпретацию экспериментальных данных вискозиметрии и исключает погрешности аппроксимации кривой течения реологической моделью и осреднения параметра вязкости. С этой целью рассмотрены вопросы аномалии вязкости и тиксотропии неньютоновских нефтей. Дано обоснование предлагаемого метода и представлено практическое приложение излагаемой методики на примере анализа гидравлической характеристики магистрального нефтепровода Атырау-Самара, по которому транспортируется смесь нефтей с частично разрушенной внутренней структурой. The problem of improving the accuracy of technological calculations for oil pipelines has become especially acute against the background of modernization of the leak detection system and development of software in the field of planning cargo flows in the trunk pipeline system. Discrepancy between hydraulic calculation results and actual pumping parameters is caused, in particular, by such factors as ignoring the multiphase oil flow nature (especially in under-loaded sections of oil pipelines laid over rough terrain), the lack of up-to-date data on the state of long-operating pipes, the use of methods for calculating friction-related energy losses based on the postulates of classical hydraulics. In this article, the authors propose a method for determining the hydraulic characteristics of a pipeline at steady state operation, pumping non-Newtonian rheologically complex oils in the range of low shear rates, which implies a direct interpretation of experimental viscometry data, excluding errors in approximating the flow curve by a rheological model and averaging the viscosity parameter. For this purpose, the anomaly of viscosity and thixotropy of non-Newtonian oils are considered. The article provides a substantiation of the proposed method and presents a practical application of the described technique by the example of the analysis of the hydraulic characteristics of the Atyrau-Samara main oil pipeline, through which an oil blend with partially destroyed internal structure is transported.

scholarly journals Stabilization of hydraulic characteristics for non-pressure pipelines

2019 ◽  
Vol 97 ◽  
pp. 05003
Author(s):  
Vladimir Orlov ◽  
Sergey Zotkin
Keyword(s):  
Water Flow ◽  
Water Flow Rate ◽  
Pipeline System ◽  
Hydraulic Characteristics ◽  
System A ◽  
Transportation Capacity ◽  
Calculation Results ◽  
Hydraulic Friction ◽  
Practical Recommendations ◽  
Hydraulic Balance

The article presents the aspects concerning the preservation of the transporting capacity of the waste water flow in the gravity pipeline during its trenchless renovation by polymer pipes. It is shown that the priority measure to preserve the required degree of self-cleaning of the restored pipeline section, as well as these ones adjacent to it, are the values of the water flow rate and filling in the pipe, which allows to provide the necessary transportation capacity of the entire pipeline system. A formula for determining the length of the rate destabilization zone is proposed and the calculation results using an automated program are given. The program algorithm includes the functions to determine the hydraulic friction coefficients of the pipeline material depending on various parameters, as well as the diameters and lengths of all sections. The essence of the calculations using an automated complex is described and the comparison of the calculation results under different conditions is made. There are given practical recommendations for the potential achievement of the hydraulic balance in the pipeline system and the creation of conditions under which the destabilization zone on the site after the repair becomes minimal.

Assessment of Certainty of Ventilation Processes Mathematical Modeling

2015 ◽  
Vol 725-726 ◽  
pp. 1255-1260
Author(s):  
Tamara Daciuk ◽  
Vera Ulyasheva
Keyword(s):  
Mathematical Modeling ◽  
Turbulent Flows ◽  
Turbulence Models ◽  
Field Measurements ◽  
Heat Emission ◽  
Emission Sources ◽  
Wide Range ◽  
Calculation Results ◽  
Definition Of ◽  
Semiempirical Models

Numerical experiment has been successfully used during recent 10-15 years to solve a wide range of thermal and hydrogasodynamic tasks. Application of mathematical modeling used to design the ventilation systems for production premises characterized by heat emission may be considered to be an effective method to obtain reasonable solutions. Results of calculation performed with numerical solution of ventilation tasks depend on turbulence model selection. Currently a large number of different turbulence models used to calculate turbulent flows are known. Testing and definition of applicability limits for semiempirical models of turbulence should be considered to be a preliminary stage of calculation. This article presents results of test calculations pertaining to thermal air process modeling in premises characterized by presence of heat emission sources performed with employment of different models of turbulence. Besides, analysis of calculation results and comparison with field measurements data are presented.

CALCULATION OF ADDITIONAL AXIAL FORCE OF ANGULAR-CONTACT BALL BEARINGS IN ROTOR SYSTEM

2016 ◽  
Vol 40 (4) ◽  
pp. 585-596
Author(s):  
Zhenhuan Ye ◽  
Zhansheng Liu ◽  
Liqin Wang
Keyword(s):  
Axial Force ◽  
Dynamic Properties ◽  
Descent Method ◽  
Rotor System ◽  
Ball Bearings ◽  
Rolling Bearings ◽  
System A ◽  
Calculation Results ◽  
Relationship Of ◽  
Raphson Method

Based on a loading-deformation relationship of bearing elements and the coordination of displacement between bearings in the rotor system, a model for calculating the additional axial force of angular-contact ball bearings in a single-rotor system is established. Nonlinear equations of this model are solved through the Rapid Descent method and Newton-Raphson method. The simulation results which are based on Gupta’s example verify that both the model and solving methods in this paper are reliable. A pair of 276927NK1W1(H) angular-contact ball bearings in symmetry in the single-rotor system is used as the example, calculation results of the additional axial force of bearings from the model in this paper and from the ISO method are compared and the influence of bearing geometry parameters and working conditions on the additional axial force is further studied. This model and its conclusions could provide the basic data and reference for analyzing the carrying ability and dynamic properties of rolling bearings.

scholarly journals The regularities of resistance and flow in pipes and wide channels

2018 ◽  
Vol 193 ◽  
pp. 02034
Author(s):  
Ilya Bryansky ◽  
Yuliya Bryanskaya ◽  
Аleksandra Оstyakova
Keyword(s):  
Comparative Analysis ◽  
Velocity Profile ◽  
Hydraulic Resistance ◽  
Cross Section ◽  
Resistance Coefficient ◽  
Hydraulic Structures ◽  
Hydraulic Characteristics ◽  
Hydraulic Resistance Coefficient ◽  
Logarithmic Velocity Profile

The data of hydraulic characteristics of flow are required to be more accurate to increase reliability and accident-free work of water conducting systems and hydraulic structures. One of the problems in hydraulic calculations is the determination of friction loss that is associated with the distribution of velocities over the cross section of the flow. The article presents a comparative analysis of the regularities of velocity distribution based on the logarithmic velocity profile and hydraulic resistance in pipes and open channels. It is revealed that the Karman parameter is associated with the second turbulence constant and depend on the hydraulic resistance coefficient. The research showed that the behavior of the second turbulence constant in the velocity profile is determined mainly by the Karman parameter. The attached illustrations picture the dependence of logarithmic velocity profile parameters based on different values of the hydraulic resistance coefficient. The results of the calculations were compared to the experimental-based Nikuradze formulas for smooth and rough pipes.

Modeling of Characteristics of Water-Ring Vacuum Pumps

2019 ◽  
pp. 70-77 ◽  
Author(s):  
N.L. Velikanov ◽  
V.A. Naumov
Keyword(s):  
Mathematical Modeling ◽  
Physical Models ◽  
Hydraulic Calculation ◽  
Suction Pressure ◽  
Gas Compression ◽  
Physical And Mathematical Modeling ◽  
Empirical Coefficients ◽  
Isothermal Gas ◽  
Pumping Units ◽  
Water Ring

Physical and mathematical modeling of characteristics of water-ring vacuum pumps has a number of specific features. Isothermal efficiency, i.e. the ratio of the isothermal gas compression power to the pump power consumed is used as an efficiency indicator. The article describes the existing methods of hydraulic calculation of pumping units. An analysis of physical models, numerical values of empirical coefficients is carried out. An improved algorithm for calculating water-ring vacuum pumps of different manufacturers in the framework of previously developed models is presented. The calculations of compressors manufactured by ZAO Beskom (VVN-3, VVN1-6, VVN1-12) and ERSTVAK (ELRS-45, ELRS-57) are considered as examples. The results of tests of vacuum pumps published by the manufacturers in the open press are used as the initial data for the calculations. The experimental dependences of the performance, power expended, isothermal efficiency of water-ring vacuum pumps on the suction pressure are presented. The results obtained make it possible to improve the accuracy and reliability of predicting the amount of displaced liquid or steam during the operation of the pumping unit.

scholarly journals Simulation of Transient Processes in a Generator-Transformer-Load System with Non-Symmetry of Phase Windings of the Stator and Saturation of the Magnetic System

2019 ◽  
pp. 939-951
Author(s):  
Gleb V. Glazyrin ◽  
Nikolay A. Mitrofanov
Keyword(s):  
Magnetic System ◽  
Synchronous Machine ◽  
Transient Processes ◽  
Stator Winding ◽  
System A ◽  
Voltage Drops ◽  
Phase Coordinates ◽  
Calculation Results ◽  
Unequal Number ◽  
Short Circuits

Transient processes of a generator-transformer-load system are considered taking into account the saturation of its magnetic system. A method is proposed for numerical simulation of the transient processes of a synchronous machine with the possibility of taking into account the asymmetry of the stator winding and the saturation of the magnetic system. The appearance of asymmetry is possible if the synchronous machine is damaged, in particular, during inter-turn short circuits in the stator winding. It is based on the direct solution of the differential equations of equilibrium of the emf and voltage drops in the windings in phase coordinates together with the equation of motion of the rotor. In this case, the contour of each phase winding of the stator is described by a separate equation, and different phase parameters can be taken into account. The mathematical model of the system is realized in the software package MATLAB. The model takes into account one of the possible types of nonsymmetry – an unequal number of turns in phase windings, which makes it possible to simulate interturn short circuits without taking into account the appearance of additional short-circuited circuits. The model was verified by comparing the transient calculation results obtained using the developed model and using the MATLAB Simulink tools. The simulation results for the idle and load modes are analyzed. The obtained results allowed to draw a conclusion about the adequacy of the realized model

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