Journal articles: 'Hydraulic servomechanisms Simulation methods'

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Muraru, Vergil, Constantin Calinoiu, Sebastian Muraru, Ana Dulgheru, and Cornelia Muraru-Ionel. "Mathematical modelling and numerical simulation of linear electro-hydraulic servomechanism with stepper motor." E3S Web of Conferences 180 (2020): 04005. http://dx.doi.org/10.1051/e3sconf/202018004005.

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The paper presents the results of research on the performance of linear electro-hydraulic servomechanisms with stepper motor, evaluated by mathematical modelling and numerical simulation with the AMESIM software package. These servomechanisms have a great potential for application, including for agricultural technical equipment. Servomechanisms of various types are used for the rapid and high precision operation of the various systems. In practice, electro-hydraulic servomechanisms have been required in the case of the systems requiring high forces or moments. These equipment are automatic hydraulic tracking systems and can be analysed with methods specific to automatic systems. The paper contains a structural description of an electro-mechanical servomechanism with stepper motor, its operation, mathematical model and its performances obtained by numerical simulation. The mathematical modelling of the electro-hydraulic servomechanism is based on the relations between the input sizes and output sizes of the equipment in its structure as well as the connection relations between these equipment. Based on the obtained results it is demonstrated that the analysis and synthesis of electro-hydraulic servomechanisms with stepper motor can be determined by numerical simulation using the AMESIM simulation software.

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Maltezos, Evangelos, Michail Papoutsidakis, and V. J. De Negri. "A STUDY OF HYDRAULIC ACTUATOR CONTROL METHODS IN SIMULATION." International Journal of Engineering Applied Sciences and Technology 04, no. 05 (October 1, 2019): 455–62. http://dx.doi.org/10.33564/ijeast.2019.v04i05.066.

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Xu, Zengguang, Xue Wang, Junrui Chai, Yuan Qin, and Yanlong Li. "Simulation of the Spatial Distribution of Hydraulic Conductivity in Porous Media through Different Methods." Mathematical Problems in Engineering 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/4321918.

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Seepage problems exist in water conservancy projects, groundwater research, and geological research, and hydraulic conductivity is an important factor that affects the seepage field. This study investigates the heterogeneity of hydraulic conductivity. Kriging methods are used to simulate the spatial distribution of hydraulic conductivity, and the application of resistivity and grain size is used to obtain hydraulic conductivity. The results agree with the experimental pumping test results, which prove that the distribution of hydraulic conductivity can be obtained economically and efficiently and in a complex and wide area.

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Pfeiffer, Friedrich, and Fredrik Borchsenius. "New Hydraulic System Modelling." Journal of Vibration and Control 10, no. 10 (October 2004): 1493–515. http://dx.doi.org/10.1177/1077546304042063.

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The efficient design of hydraulic systems requires fast simulation methods. In most simulation programs, the hydraulic components are coupled by compressible joints. Since the compressibility of oil is very small, this leads to stiff differential equations. To avoid these difficulties stiff elastic couplings can be replaced by algebraic and, in some cases, unilateral constraints. Examples for hydraulic components with unilateral behavior are check valves, cylinders with stop limits and fluid volumes, in which cavitation can occur. The resulting complementarity equations can be solved with a standard Lemke algorithm. Compared to conventional methods, this leads to a significant reduction of computational effort.

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Hlbočan, Peter, Marta Murgašová, Zoltán Csuka, and Michal Varchola. "Hydraulic Design of an Axial Runner Using Classical Methods and CFD Simulation." MATEC Web of Conferences 369 (2022): 01008. http://dx.doi.org/10.1051/matecconf/202236901008.

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The paper deals with the principles of hydraulic design of runners of axial turbines or pumps. The procedures of classical methods of hydraulic design of primary runner geometry and the possibilities of subsequent optimization of this geometry by CFD simulation are presented. In the paper, the advantages of the procedure of hydraulic design of the primary runner geometry of a tubular Kaplan turbine with the application of the classical methods and the subsequent CFD simulation are shown on a specific example. The purpose of the CFD simulation is to verify the achievement of the required parameters of the designed runner geometry and its possible fine-tuning and optimization.

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Pellicciari, Marcello, Giovanni Berselli, Mirko Ori, and Francesco Leali. "The Role of Co-Simulation in the Integrated Design of High-Dynamics Servomechanisms: An Experimental Evaluation." Applied Mechanics and Materials 278-280 (January 2013): 1758–64. http://dx.doi.org/10.4028/www.scientific.net/amm.278-280.1758.

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This paper reports about the design and modeling process of high performance servo-actuated mechanisms for automatic machines. Besides being a delicate and time consuming process, coupled simulations based on virtual prototyping finally offer the chance to integrate engineering methods proper of control system engineering and mechanical design. In particular, the main target of this work is to investigate how different virtual prototyping approaches, each having increasing level of detail, can contribute to the appropriate prediction of the expected machine performance. These results are then compared with experimental data obtained on a real servomechanism prototype. The comparison quantitatively demonstrate the improvement on torque prediction and position error reduction when detailed models of the controller and the electric motor dynamics are coupled with the mechanical system model.

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Fei, Ye, Qiong Wu, and Hai Yang Yu. "Dynamic Simulation of Hydraulic Truck Crane Hoisting System Based on AMESim." Applied Mechanics and Materials 29-32 (August 2010): 2031–36. http://dx.doi.org/10.4028/www.scientific.net/amm.29-32.2031.

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This paper is made from a certain type of truck crane hydraulic lifting mechanism system as an object, then the second lifting working condition is analyzed. With AMESim, according to the hydraulic system diagram building lifting mechanism hydraulic system simulation model, hereby corresponding simulation conditions is set and the effects of secondary slide response on input signal, hoisting load, discharge and speed of pump, fluid resistance of one-way throttle is studied. This research on truck crane hoisting mechanism hydraulic system provides the theory basis for the design improvement, the relevant research methods and means have reference on the research of other engineering machinery hydraulic system working characteristics.

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Skorek, Grzegorz. "Study of Losses and Energy Efficiency of Hydrostatic Drives with Hydraulic Cylinder." Polish Maritime Research 25, no. 4 (December 1, 2018): 114–28. http://dx.doi.org/10.2478/pomr-2018-0138.

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Abstract Energy efficiency of hydrostatic transmissions, and especially efficiencies of drives with motor speed controlled by throttle, as well as efficiency of hydraulic servomechanisms can in fact be higher than the efficiency values most frequently given by the respective literature in this field. With the progress achieved in recent years in the development of hydraulic systems it is becoming necessary to develop methods for precise energy efficiency calculation of such systems. It is difficult to imagine that more and more, better and better machines and control elements could be used without the possibility of a mathematical tool at our disposal to enable an accurate analysis and assessment of behavior of the system in which such machines and control elements have been applied. The paper discusses energy savings using mathematical model of losses in elements, the energy efficiency of the system. There are possibilities to reduce energy losses in proportional control systems (in the pump, in the throttle control unit, especially in the cylinder), and thus to improve the energy efficiency of the throttling manifold. The considerations allow for comparison of the loss power resulting from the applied hydraulic control structure of the hydraulic cylinder and the power consumed by the pump from the electric motor that drives it, the power necessary to provide pump-driven hydraulic cylinder. The article shows the impact on the output (useful) power consumed in the considered systems, and the impact on the power consumed of the loss power in the individual elements. The paper presents also formulas of loss power, formulas of energy efficiency connected with investigated hydrostatic drives, two schematic diagrams of hydraulic systems, their principle of operation and problems of studying losses in elements and energy efficiency characteristics of systems consisting of a feed assembly, control set and cylinder. It also includes a subject matter connected with an energy loss power of hydrostatic systems with hydraulic cylinder controlled by proportional directional control valve. Diagrams of loss power of two hydraulic systems worked at the same parameters of speed and load of a cylinder, which were different due to structure and ability of energy saving, were presented and compared.

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Guo, Xu Sheng, Quan Cai Li, and Ju Liang Xiao. "Dynamic Characteristics Simulation of the Digital Hydraulic Cylinder Based on AMESim." Advanced Materials Research 625 (December 2012): 75–78. http://dx.doi.org/10.4028/www.scientific.net/amr.625.75.

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Hydraulic transmission has a wide range of applications and attains rapid development. As the traditional methods of mathematic modeling in the design of the electro-hydraulic control system are very complex, making the design and debugging cycle of the hydraulic system longer. Thus in this paper, using the AMESim which is a senior modeling software facing engineering task design, does the modeling and simulation calculations for one kind of digital hydraulic cylinder. We get its simulation in the application of the actual working condition. At the same time, we optimize the simulation parameters and analyze the simulation results. The simulation results and analysis can provide certain reference value for the design, debugging and subsequent improvement of the digital hydraulic cylinder. According to the simulation results, it can meet different operational requirements by making appropriate compensation and adjustment in practical applications.

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Yan, Jing. "Hydraulic System Simulation Research of Demolishing Robots Based on Matlab." Advanced Materials Research 753-755 (August 2013): 2757–60. http://dx.doi.org/10.4028/www.scientific.net/amr.753-755.2757.

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Modular modeling methods based on the reasonable simplifying and supposing of hydraulic system of demolishing robots are proposed in this paper, dynamic mathematical model of each hydraulic element of demolishing robots is set up by the dynamic system analysis software package Simulink of Matlab, response characteristic curve is obtained by the simulation, and analysis of the simulation results is operated in this paper. The experimental results explicate that the hydraulic system is stably, real-time, low-cost, and easy to expand; it can meet the applying requirements of demolishing robots, and it provides the theory basis for the project applying of the hydraulic system of demolishing robots.

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Zhou, Wen Chao, Wei Zhou, Cun Ping Liu, and Shan Hua Xiao. "Simulation and Optimization on Dynamic Hydraulic Drawing for Spiral Bottom Shell Parts." Applied Mechanics and Materials 496-500 (January 2014): 935–38. http://dx.doi.org/10.4028/www.scientific.net/amm.496-500.935.

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The dynamic hydraulic drawing simulation is a valid method that reduces costs, increases quality and discovers hydraulic forming process problems.The simulation process of hydraulic drawing for spiral bottom brake shell parts with space surface feature was investigated and the optimal processing parameters were acquired by using Dynaform software. The results showed that model approaches, model methods, meshing and parameters setting were the foundation of hydraulic drawing simulation and the optimized control of holder force and fluid pressure were the key factors for preventing defects during hydraulic deep drawing. Meanwhile, the suitable blank shape was found good for reducing the defects of Wall Thickness Unevenness and oral flange earing, etc.

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Sepehri, N., G. A. M. Dumont, P. D. Lawrence, and F. Sassani. "Cascade control of hydraulically actuated manipulators." Robotica 8, no. 3 (July 1990): 207–16. http://dx.doi.org/10.1017/s0263574700000060.

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SUMMARYA fundamental study on the control of hydraulically actuated robots is presented. Dynamic modelling is performed in both time-domain and frequency-domain. It is shown that the inclusion of hydraulic elements increases the order of the system. Hydraulic compliance is the most effective factor in this regard.Three distinct control strategies are applied. Their performances are evaluated and compared. All three methods are exemplified with a two link hydraulic robot in a computer simulation. The robot has the same hydraulic configuration as many existing industrial manipulators. The simulation program is written in ACSL (Advanced Continuous Simulation Language) running on a VAX 11/750.

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Huang, Qitao, Peng Wang, Yudong Liu, and Bowen Li. "Modeling and Simulation of Hydraulic Power Take-Off Based on AQWA." Energies 15, no. 11 (May 26, 2022): 3918. http://dx.doi.org/10.3390/en15113918.

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The AQWA software is often used to perform hydrodynamic analysis, and it is highly convenient for performing frequency domain simulations of Pelamis-like wave energy converters. However, hydraulic power take-off (PTO) must be simplified to a linear damping model or a Coulomb torque model when performing a time domain simulation. Although these simulation methods can reduce the computational complexity, they may not accurately reflect the energy capture characteristics of the hydraulic PTO. By analyzing system factors such as the flow and pressure of each branch of the hydraulic PTO, the output torque of the hydraulic cylinder to the buoy, and the electromagnetic torque of the generator, a relatively complete hydraulic PTO model is obtained, and the model is applied to AQWA using the FORTRAN language. Comparing and analyzing the simulation results of the linear damping model, the Coulomb torque model, and the hydraulic PTO, we found that the simulation results obtained by the linear damping model are quite different from those of the hydraulic PTO, while the torque characteristics, kinematic characteristics and energy capture characteristics of the Coulomb torque model are closer to those of the hydraulic PTO model. Therefore, it is more appropriate to simplify hydraulic PTO to a Coulomb torque model based on AQWA.

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Wang, Jincheng, Qin Wang, and Ming Ding. "Review on neutronic/thermal-hydraulic coupling simulation methods for nuclear reactor analysis." Annals of Nuclear Energy 137 (March 2020): 107165. http://dx.doi.org/10.1016/j.anucene.2019.107165.

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Biscarini, Chiara, Silvia Di Francesco, Fernando Nardi, and Piergiorgio Manciola. "Detailed Simulation of Complex Hydraulic Problems with Macroscopic and Mesoscopic Mathematical Methods." Mathematical Problems in Engineering 2013 (2013): 1–14. http://dx.doi.org/10.1155/2013/928309.

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The numerical simulation of fast-moving fronts originating from dam or levee breaches is a challenging task for small scale engineering projects. In this work, the use of fully three-dimensional Navier-Stokes (NS) equations and lattice Boltzmann method (LBM) is proposed for testing the validity of, respectively, macroscopic and mesoscopic mathematical models. Macroscopic simulations are performed employing an open-source computational fluid dynamics (CFD) code that solves the NS combined with the volume of fluid (VOF) multiphase method to represent free-surface flows. The mesoscopic model is a front-tracking experimental variant of the LBM. In the proposed LBM the air-gas interface is represented as a surface with zero thickness that handles the passage of the density field from the light to the dense phase and vice versa. A single set of LBM equations represents the liquid phase, while the free surface is characterized by an additional variable, the liquid volume fraction. Case studies show advantages and disadvantages of the proposed LBM and NS with specific regard to the computational efficiency and accuracy in dealing with the simulation of flows through complex geometries. In particular, the validation of the model application is developed by simulating the flow propagating through a synthetic urban setting and comparing results with analytical and experimental laboratory measurements.

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Kaleris, V., C. Hadjitheodorou, and A. C. Demetracopoulos. "Numerical simulation of field methods for estimating hydraulic conductivity and concentration profiles." Journal of Hydrology 171, no. 3-4 (October 1995): 319–53. http://dx.doi.org/10.1016/0022-1694(94)06012-t.

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Zhu, Dan Dan. "The Simulation Analysis of Virtual Prototype of Hydraulic Shovel." Applied Mechanics and Materials 614 (September 2014): 584–87. http://dx.doi.org/10.4028/www.scientific.net/amm.614.584.

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The application of dynamic simulation software ADAMS virtual prototype was carried out on the powerful triangle structure of excavator analysis methods, including environmental Settings; add parts import, motion pair, driving Settings, the simulation calculation and image processing, etc. Application by ADAMS virtual prototype technology to "strong triangle" structure modeling and analysis, the performance of the excavator movement process and intuitive parameters change, for the realization of the excavator laid the foundation of virtual design and dynamic.

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Shen, Wei, Jihai Jiang, Xiaoyu Su, and Hamid Reza Karimi. "A new type of hydraulic cylinder system controlled by the new-type hydraulic transformer." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 228, no. 12 (December 12, 2013): 2233–45. http://dx.doi.org/10.1177/0954406213515646.

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In order to enhance the efficiency of the hydraulic system, one new-type hydraulic transformer is presented in this paper. First, the basic structure and the principle of the new-type hydraulic transformer are explained. Then, the mathematical models including both the inner and outer loops are analyzed. Moreover, two kinds of control methods are discussed corresponding to the two loops, respectively. Furthermore, the proposed strategies are translated into the simulation languages, and the simulation is made in Simulink. Finally, the prototypes of new-type hydraulic transformer and the test rig are constructed to test the performance. Both the simulated and experimental results show that the new-type hydraulic transformer can be used in the practical condition, and the proposed control algorithm is suitable.

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Bogdevicius, Marijonas, Jolanta Janutėnienė, and Oleg Vladimirov. "Simulation of Hydrodynamics Processes of Hydraulic Braking System of Vehicle." Solid State Phenomena 147-149 (January 2009): 296–301. http://dx.doi.org/10.4028/www.scientific.net/ssp.147-149.296.

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The 3D vehicle with the hydraulic braking system and disc brake with the wheel has been investigated. The dynamic models of the disk brake assembly and the wheel have been constructed. The automobile hydraulic braking system consisting of two contours is considered. . The mathematical model of the hydraulic braking system is presented, where the flow of liquid and the interaction of liquid with the rigid bodies are taken into account. The flow of fluid in a hydraulic system is described by a system of equations of a hyperbolic type, which is solved by a characteristics method. During the mathematical simulations and natural experimentations the following results were achieved. The systems of equations of dynamic models’ motions are solved by numerical methods. The dynamic characteristics of the braking system of the automobile are obtained. The results of extreme braking tests and calculations are presented.

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Wei, Xiao Hui, Yin Yin, Heng Chen, and Hong Nie. "Modeling and Simulation of Aircraft Nose Landing Gear Emergency Lowering Using Co-Simulation Method." Applied Mechanics and Materials 215-216 (November 2012): 1213–18. http://dx.doi.org/10.4028/www.scientific.net/amm.215-216.1213.

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This paper builds dynamical models and hydraulic system models of retraction/lowering of some regional aircraft nose landing gear respectively based on the software LMS VL motion and AMESim. The simulation analysis result was proved to be credible by checking with that of ground test. The peak oil return pressure with the critical damping force can be obtained by analyzing the hydraulic damping characteristic of actuator cylinder during landing gear emergency lowering based on methods of estimation and co-simulation. The results indicate that the damping characteristic of actuator cylinder plays an important role in emergency lowering. Only when the damping force breaks through the critical value, can the landing gear succeed in emergency lowering and being locked. However, the little damping force will result in great impact load while lowering. Thus, damping force should be changed only when emergency lowering.

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Wei, Jiafu, Hao Wang, Yuanchu Cheng, and Xinran Guo. "Dynamics Analysis for Hydroturbine Regulating System Based on Matrix Model." Mathematical Problems in Engineering 2017 (2017): 1–6. http://dx.doi.org/10.1155/2017/3565296.

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The hydraulic turbine model is the key factor which affects the analysis precision of the hydraulic turbine governing system. This paper discusses the basic principle of the hydraulic turbine matrix model and gives two methods to realize. Using the characteristic matrix to describe unit flow and torque and their relationship with the opening and unit speed, it can accurately represent the nonlinear characteristics of the turbine, effectively improve the convergence of simulation process, and meet the needs of high precision real-time simulation of power system. Through the simulation of a number of power stations, it indicates that, by analyzing the dynamic process of the hydraulic turbine regulating with 5-order matrix model, the calculation results and field test data will have good consistency, and it can better meet the needs of power system dynamic simulation.

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Shi, Yuanling, and Pingsong Zhang. "Modeling and Dynamic Performance Analysis of Hydraulic Top Drive Main Transmission System with Long Hydraulic Pipelines." Geofluids 2022 (April 16, 2022): 1–15. http://dx.doi.org/10.1155/2022/1304176.

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Hydraulic top drive is the main power component used to drive drilling tools rotating to drill a hole for drilling rigs. Its main transmission system was built with hydraulic power source and hydraulic actuators. During the drilling procession, the hydraulic top drive is mounted on a derrick, and moving along its vertical guide rails. The hydraulic power station is usually placed on the drilling platform or the ground. In that way, long pipelines are needed to connect the hydraulic pumps and hydraulic motors. Thus, the effects on the performance of hydraulic top drive should not be neglected. A mathematical model of hydraulic top drive main transmission with differential equation of hydraulic units and state space equation of hydraulic long pipelines was deduced in this research. A simulation model was built using the AMESim software. And field drilling test of the hydraulic top drive was carried out in Songliao Basin Drilling Project (SK-II) well site. To verify and modify the virtual model, a comparison analysis was performed by setting the parameters and load of the three methods at the same values. The result of comparison shows that the simulation results are very close to the theoretical results and field drilling test data. Thus, the dynamic characteristics could be analyzed by this simulation model. Dynamic characteristics of the hydraulic top drive with different length and various diameters of pipelines were studied. The simulation results demonstrate that pipeline lengths and pipeline diameters affect the system in different laws, and it needs to comprehensively consider the system response speed, overshoot, and steady-state characteristics when choosing the size of pipelines for hydraulic top drive.

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Khoreshok, Aleksey, Andrey Kuznetsov, and Anton Shalkov. "Simulation and Field Measurements of Reliability Parameters of Dump Truck Hydraulic System." E3S Web of Conferences 41 (2018): 03004. http://dx.doi.org/10.1051/e3sconf/20184103004.

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Paper studies the problem of non-failure operation of dump trucks hydraulic system that is exploited in the climatic conditions of Kuzbass region. The main characteristic of the Kuzbass climate is hardly continental, so, it has sharp fluctuations in ambient temperature for seasons, for a month or even a day. To analyze the negative factors affecting the operation of the dump trucks hydraulic system a systematic approach was used, based on the methodology of SADT structural analysis. The result of field and cameral researches identified that the major negative factor is instability of kinematic viscosity of working fluids used in the hydraulic system of mining dump trucks over a wide range of ambient temperatures. There were offered the further ways for methods to stabilize the parameters of working fluids in the hydraulic system of dump trucks.

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Zhu, Xin Cai, Lei Guo, You Qing Ding, and Shun Hong Lin. "Modeling and Simulation of Hydraulic Turnover Device for Large Bearing House." Applied Mechanics and Materials 226-228 (November 2012): 660–64. http://dx.doi.org/10.4028/www.scientific.net/amm.226-228.660.

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The geometric models of the hydraulic turnover device are constructed by using three -dimensional modeling software UG, and then they are induced into simulation software ADAMS by a sharing data format. By using ADAMS, models are further simplified and the virtual prototype is established. By using the associated model, the simulation of the hydraulic turnover device is analyzed in ADAMS. Compared with the traditional methods of using physical prototypes, the movement processes and relevant parameters of the hydraulic turnover device can be effectively obtained by means of this method. Furthermore, the quality of the constraint relations between the parts is very important in terms of the accuracy of the model simulation analysis. This simulation results accord with the practical situation, which indicates that the operation is stable and the efficiency is high. It provides a theoretical basis for the practical design of the hydraulic turnover device, which shows that the combination of ADAMS and UG works well.

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Roos Launchbury, D., E. Casartelli, and L. Mangani. "Lattice Boltzmann simulation of the ERCOFTAC pump impeller." IOP Conference Series: Earth and Environmental Science 1079, no. 1 (September 1, 2022): 012074. http://dx.doi.org/10.1088/1755-1315/1079/1/012074.

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Abstract The analysis of unsteady flows is becoming more and more important in the field of hydraulic turbomachinery applications, both for stable and especially for unstable operating conditions and other transient phenomena. Unsteady Reynolds-averaged Navier-Stokes (RANS) methods for incompressible flows, implemented via finite volume or finite element approaches, reach their limit in both accuracy and acceptable computational time. The accuracy mainly suffers due to the strong dependence of the solution on turbulence model variants. Furthermore, incompressibility of the flow and the linked implicit pressure equation makes large eddy simulations (LES) of Navier-Stokes-based methods for such flows prohibitively expensive. An alternative to Navier-Stokes fluid solvers are methods based on the solution of the discrete Boltzmann equation, so-called Lattice Boltzmann Methods (LBM). The purpose of this work is to present first results of an ongoing project involving the simulation of unsteady hydraulic turbomachines at high Reynolds numbers. For this purpose, the ERCOFTAC pump impeller was selected as a test case. Results obtained with the current implementation of the in-house code suggest, that the present methodology could provide a viable alternative for the analysis of unsteady flow phenomena in hydromachines.

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TANAKA, Kazuhiro, Koji TAKAHASHI, Keiko NAKAGAWA, and Hajime TAJIMA. "Simulation and Design Method of Hydraulic Deceleration Valve by using Bond Graph Methods." Hydraulics & Pneumatics 20, no. 1 (1988): 64–70. http://dx.doi.org/10.5739/jfps1970.20.64.

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Abraham, Edo, and Ivan Stoianov. "Efficient Preconditioned Iterative Methods for Hydraulic Simulation of Large Scale Water Distribution Networks." Procedia Engineering 119 (2015): 623–32. http://dx.doi.org/10.1016/j.proeng.2015.08.915.

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Zhao, Rui Ying, and Xin Wang. "Research on Power Adaptive Control Method for Hydraulic Motor Grader Based on Simulink/AMESim." Applied Mechanics and Materials 135-136 (October 2011): 793–99. http://dx.doi.org/10.4028/www.scientific.net/amm.135-136.793.

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A method of power adaptive control for hydraulic motor graders is provided, including the dynamic regulation methods of pump and motor and realization algorithms related. The simulation models of hydraulic transmission system and the control system are established in AMESim and Simulink respectively. By using these two softwares, the models are co-simulated. The co-simulation results verify the feasibility and effectiveness of the control system.

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Viti, Nicolò, Daniel Valero, and Carlo Gualtieri. "Numerical Simulation of Hydraulic Jumps. Part 2: Recent Results and Future Outlook." Water 11, no. 1 (December 24, 2018): 28. http://dx.doi.org/10.3390/w11010028.

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During the past two decades, hydraulic jumps have been investigated using Computational Fluid Dynamics (CFD). The second part of this two-part study is devoted to the state-of-the-art of the numerical simulation of the hydraulic jump. First, the most widely-used CFD approaches, namely the Reynolds-Averaged Navier–Stokes (RANS), the Large Eddy Simulation (LES), the Direct Numerical Simulation (DNS), the hybrid RANS-LES method Detached Eddy Simulation (DES), as well as the Smoothed Particle Hydrodynamics (SPH), are introduced pointing out their main characteristics also in the context of the best practices for CFD modeling of environmental flows. Second, the literature on numerical simulations of the hydraulic jump is presented and discussed. It was observed that the RANS modeling approach is able to provide accurate results for the mean flow variables, while high-fidelity methods, such as LES and DES, can properly reproduce turbulence quantities of the hydraulic jump. Although computationally very expensive, the first DNS on the hydraulic jump led to important findings about the structure of the hydraulic jump and scale effects. Similarly, application of the Lagrangian meshless SPH method provided interesting results, notwithstanding the lower research activity. At the end, despite the promising results still available, it is expected that with the increase in the computational capabilities, the RANS-based numerical studies of the hydraulic jump will approach the prototype scale problems, which are of great relevance for hydraulic engineers, while the application at this scale of the most advanced tools, such as LES and DNS, is still beyond expectations for the foreseeable future. Knowledge of the uncertainty associated with RANS modeling may allow the careful design of new hydraulic structures through the available CFD tools.

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Li, Jun, Huanliang Li, Hongxin Cui, and Yawei Zhu. "Nonlinear dynamics characteristics and influence factors analysis of servo hydraulic cylinder." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, no. 20 (November 6, 2017): 3629–38. http://dx.doi.org/10.1177/0954406217740166.

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Aiming at problems of vibration, impact, and noise, the nonlinear dynamic characteristics of servo hydraulic cylinder are studied by using combination of theoretical derivation and simulation experiment methods. The nonlinear effect rules of spring force and friction force are analyzed based on nonlinear dynamic theory; it can be derived that the coupling effect rules of nonlinear spring force and friction force can be described by Duffing–Van Der Pol equation. The dynamic simulation model of servo hydraulic cylinder is established by using SimHydraulics software. The numerical simulation and experiment results showed that nonlinear vibration of servo hydraulic cylinder is mainly caused by exciting force, spring force, and friction force; the system has different motion states when the parameters take different values, which lays a good foundation for the optimal designs and precise control of hydraulic cylinder.

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ShengQing, Yang, Ji Hong, Li SenLin, Sun Fei, and Wang SuYan. "Prediction and verification for the models of temperature rising by medium bubbles in hydraulic system." Advances in Mechanical Engineering 14, no. 3 (March 2022): 168781322210854. http://dx.doi.org/10.1177/16878132221085431.

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In order to obtain the influence of the medium bubble contents on temperature rising characteristics of a hydraulic system, the working hydraulic system of a wheel loader was taken as the research object. By carrying out the comparison experiments of the hydraulic system with and without de-aeration devices on a 5-ton wheel loader, the air bubble contents and concerning temperatures were obtained. To identify the factors which have impact on temperature rising of the hydraulic system, the head chamber of boom cylinder is taken to analyze, and the temperature rising expression in a volume were deduced. By the utilization of the thermal hydraulic library, combining with mechanism and control libraries on AMESim simulation platform, the integrated simulation model of the whole system was established and verified, meanwhile, the simulation was carried out from aspects in different air contents and initial chamber temperatures. From the simulation, the prediction models of the air contents to temperature rising, and the pressures to temperature rising were predicted. Finally, the correctness of the prediction models are verified by experiment data and showing good results, which can be used to enrich and improve the calculation and evaluation methods of heat generation to any other hydraulic systems.

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Gao, Zhiwei, Lianfa Yang, Jianping Ma, Chenchen Don, Xu Liu, and Lin Song. "Detection methods for springback of assembled camshaft under hydraulic expansion." Journal of Physics: Conference Series 2125, no. 1 (November 1, 2021): 012026. http://dx.doi.org/10.1088/1742-6596/2125/1/012026.

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Abstract The assembled camshaft under hydraulic expansion has the advantages of low cost, lightweight and high performance, which is an advanced technology with great development potential. By applying the tube hydroforming to the fabrication of assembled camshaft, the expansion principle is due to the different degrees of resilience of the cam and the shaft. Therefore, the effective detection method of elastic recovery of camshaft is of great significance to research how to improve the connection strength of the assembled camshaft. This paper introduces several springback detection methods for assembled camshaft under hydraulic expansion, namely resistance strain detection method, gap dynamic detection method and finite element simulation.

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Huber, David, Viktoria Illyés, Veronika Turewicz, Gregor Götzl, Andreas Hammer, and Karl Ponweiser. "Novel District Heating Systems: Methods and Simulation Results." Energies 14, no. 15 (July 23, 2021): 4450. http://dx.doi.org/10.3390/en14154450.

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Fifth-generation district heating and cooling (5th DHC) systems offer promising approaches to decarbonizing space heating, cooling and domestic hot water supply. By using these systems, clustered buildings combined with industrial waste heat can achieve a net-zero energy balance on a variety of time scales. Thanks to the low exergy approach, these systems are highly efficient. As part of the Smart Anergy Quarter Baden (SANBA) project, the thermal energy grid simulation tool TEGSim has been further developed and used to design an ultra-low-temperature district heating (ULTDH) network with hydraulic and thermal components fitted to the specific regional characteristics of the investigated case. Borehole thermal energy storage (BTES) used as seasonal storage ensures long-term feasibility. The annual discrepancy of input of thermal energy provided by space cooling and output of energy demanded by space heating and domestic hot water is supplied by an external low-grade industrial waste heat source. This paper presents the functionality of the simulation and shows how to interpret the findings concerning the design of all components and their interplay, energy consumption and efficiencies.

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Kim, Hyun, Ho Keum, and Kun Han. "Real-Time Urban Inundation Prediction Combining Hydraulic and Probabilistic Methods." Water 11, no. 2 (February 8, 2019): 293. http://dx.doi.org/10.3390/w11020293.

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Damage caused by flash floods is increasing due to urbanization and climate change, thus it is important to recognize floods in advance. The current physical hydraulic runoff model has been used to predict inundation in urban areas. Even though the physical calculation process is astute and elaborate, it has several shortcomings in regard to real-time flood prediction. The physical model requires various data, such as rainfall, hydrological parameters, and one-/two-dimensional (1D/2D) urban flood simulations. In addition, it is difficult to secure lead time because of the considerable simulation time required. This study presents an immediate solution to these problems by combining hydraulic and probabilistic methods. The accumulative overflows from manholes and an inundation map were predicted within the study area. That is, the method for predicting manhole overflows and an inundation map from rainfall in an urban area is proposed based on results from hydraulic simulations and uncertainty analysis. The Second Verification Algorithm of Nonlinear Auto-Regressive with eXogenous inputs (SVNARX) model is used to learn the relationship between rainfall and overflow, which is calculated from the U.S. Environmental Protection Agency’s Storm Water Management Model (SWMM). In addition, a Self-Organizing Feature Map (SOFM) is used to suggest the proper inundation area by clustering inundation maps from a 2D flood simulation model based on manhole overflow from SWMM. The results from two artificial neural networks (SVNARX and SOFM) were estimated in parallel and interpolated to provide prediction in a short period of time. Real-time flood prediction with the hydraulic and probabilistic models suggested in this study improves the accuracy of the predicted flood inundation map and secures lead time. Through the presented method, the goodness of fit of the inundation area reached 80.4% compared with the verified 2D inundation model.

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Ren, Qingshan, Yaodong Jiang, Pengpeng Wang, Guangjie Wu, and Nima Noraei Danesh. "Experimental and Numerical Simulation Study of Hydraulic Fracture Propagation during Coalbed Methane Development." Geofluids 2021 (August 17, 2021): 1–12. http://dx.doi.org/10.1155/2021/3632997.

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The extraction of low-permeability coalbed methane (CBM) has the dual significance of energy utilization and safe mining. Understanding hydraulic fracturing mechanism is vital to successful development of CBM. Therefore, it is important to improve the law of hydraulic fracture propagation in coal and rigorously study the influencing factors. In this paper, laboratory experiments and numerical simulation methods were used to investigate the hydraulic fracture propagation law of coal in coalbed methane reservoir with natural fractures. The results show that the maximum and minimum horizontal in situ stress and the difference in stress significantly affect the direction of crack propagation. The elastic modulus of coal, the mechanical properties of natural fractures, and the injection rate can affect the fracture length, fracture width, and the amount of fracturing fluid injected. To ensure the effectiveness of hydraulic fracturing, a reservoir environment with a certain horizontal stress difference under specific reservoir conditions can ensure the increase of fractured reservoir and the controllability of fracture expansion direction. In order to increase the volume of fractured reservoir and fracture length, the pumping speed of fracturing fluid should not be too high. The existence of stress shadow effect causes the hydraulic fracture to propagate along the main fracture track, where the branch fracture cannot extend too far. Complex fractures are the main hydraulic fracture typology in coalbed methane reservoir with natural fractures. The results can provide a benchmark for optimal design of hydraulic fracturing in coalbed methane reservoirs.

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Potakhov, D. A., and Ya S. Vatulin. "NUMERICAL CALCULATION OF THE HYDROLIQUID LEAKAGE THROUGH THE RADIAL CLEARANCE OF THE CONNECTED ELEMENTS ON THE TOWER CRANE HYDROCILINDER." Russian Automobile and Highway Industry Journal 16, no. 1 (March 1, 2019): 18–30. http://dx.doi.org/10.26518/2071-7296-2019-1-18-30.

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Introduction. The authors present the numerical calculation of the hydro-liquid leakage throughthe radial clearance of the “piston - hydraulic cylinder” conjugate node on the basis of determiningthe sealing elements’ resource of the tower crane hydraulic cylinder.Materials and methods. The authors use the method of mathematical modeling, which makes it possible to model the containing elements’ interaction of different physical nature on the unified methodological basis. Moreover, the paper presents such simulation systems as Simulation (finite element method), Flow Simulation (finite volume method) of the SolidWorks CAD program and Simulink Matlab with expansion packs.Results. As a result, the authors demonstrate the three-dimensional and irregular cross-section conjugation model of the radial clearance in the “piston - hydraulic cylinder” conjugate node. In addition, the authors propose the calculating method of the hydraulic cylinder tightness. Such method establishes the following scheme: “load on the hydraulic cylinder —number of operating cycles — uneven radial clearance between the piston and the liner — amount of fluid leakage — shrinkage of the rod”.Discussion and conclusions. The results of the research make it possible to increase the reliability of the power hydraulic cylinders of the road construction machines and equipment.

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Lu, Weiyong, and Changchun He. "Numerical simulation on the simultaneous stress interference of parallel multiple hydraulic fractures." Energy Exploration & Exploitation 39, no. 4 (March 31, 2021): 1143–61. http://dx.doi.org/10.1177/01445987211001955.

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During horizontal well staged fracturing, there is stress interference between multiple transverse fractures in the same perforation cluster. Theoretical analysis and numerical calculation methods are applied in this study. We analysed the mechanism of induced stress interference in a single fracture under different fracture spacings and principal stress ratios. We also investigated the hydraulic fracture morphology and synchronous expansion process under different fracture spacings and principal stress ratios. The results show that the essence of induced stress is the stress increment in the area around the hydraulic fracture. Induced stress had a dual role in the fracturing process. It created favourable ground stress conditions for the diversion of hydraulic fractures and the formation of complex fracture network systems, inhibited fracture expansion in local areas, stopped hydraulic fractures, and prevented the formation of effective fractures. The curves of the maximum principal stress, minimum principal stress, and induced principal stress difference with distance under different fracture lengths, different fracture spacings, and different principal stress ratios were consistent overall. With a small fracture spacing and a small principal stress ratio, intermediate hydraulic fractures were difficult to initiate or arrest soon after initiation, fractures did not expand easily, and the expansion speed of lateral hydraulic fractures was fast. Moreover, with a smaller fracture spacing and a smaller principal stress ratio, hydraulic fractures were more prone to steering, and even new fractures were produced in the minimum principal stress direction, which was beneficial to the fracture network communication in the reservoir. When the local stress and fracture spacing were appropriate, the intermediate fracture could expand normally, which could effectively increase the reservoir permeability.

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Yang, Kai, Ali E. Yılmaz, and Carlos Torres-Verdín. "A goal-oriented framework for rapid integral-equation-based simulation of borehole resistivity measurements of 3D hydraulic fractures." GEOPHYSICS 82, no. 2 (March 1, 2017): D123—D133. http://dx.doi.org/10.1190/geo2016-0179.1.

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We have developed a goal-oriented framework for fast integral-equation-based simulation of low-frequency borehole resistivity measurements of 3D arbitrarily shaped hydraulic fractures. The framework explores the possibility of applying various approximate integral-equation methods to simulate borehole electromagnetic (EM) measurements acquired in the vicinity of 3D hydraulic fractures generated with electrically conductive proppant. It includes four approximate methods that are progressively more accurate, costly, and rigorous. Each method is used to approximate the method-of-moments solution of the integral equation and to evaluate/extract quantities of interest, e.g., bucked signals detected at receivers. When compared with rigorous fast Fourier transform (FFT)-accelerated method-of-moments solutions, the numerical results obtained with the four methods indicate the following (1) All of the approximate methods capture the main features of the quantities of interest, e.g., the shape of detected signals. (2) Different approximate methods exhibit different accuracies and efficiencies in the simulation of EM scattering from various 3D fractures. (3) The identified approximate method achieves accurate results (error [Formula: see text]) while reducing the simulation time by a factor of 2–1000 compared with the FFT-accelerated rigorous method. Thus, our approximate simulation framework is a promising candidate for evaluating the Jacobian matrix in the fast inversion of borehole EM measurements to detect and assess the geometry of 3D hydraulic fractures generated with electrically conductive proppant.

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Zolghadr, Masih, Mohamad R. Rafiee, Fatemeh Esmaeilmanesh, Abazar Fathi, Ravi Prakash Tripathi, Upaka Rathnayake, Sreedhar Rao Gunakala, and Hazi Mohammad Azamathulla. "Computation of Time of Concentration Based on Two-Dimensional Hydraulic Simulation." Water 14, no. 19 (October 7, 2022): 3155. http://dx.doi.org/10.3390/w14193155.

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Time of concentration (TC) is a parameter in runoff estimation, used to study and design different types of projects in watersheds. Any error in TC calculation leads to an inaccurate estimation of the design flow, which can lead to over-sizing or under-sizing of designed facilities that can have great economic and environmental consequences. Therefore, choosing the correct method to estimate TC is of great importance. Due to the diversity of estimation methods in the literature, the obtained TC values are different. This study aims to present a new method to calculate TC, based on its main concept, i.e., the time required for a water parcel to reach its outlet from the farthest hydrological point of a watershed. A two-dimensional hydraulic simulation was used to model the water parcel travel. A watershed was selected as a case study, and its time of concentration was determined by salt solution tracing. The field measurement results were used for calibration of the numerical simulation model. Meanwhile, 31 empirical relations in the literature were reviewed to determine the most accurate ones. Estimated TC values were compared with the measured ones, and the relative error percentage was used to evaluate the accuracy of the result. In the empirical TC methods, the maximum error was above 300%, and the minimum error was 6.7% for the field studied area. The relative errors of hydraulic simulation outputs were between 3 and 27%. The results showed that only three empirical methods, namely Simas and Hawkins, SCSlag, and Yen and Chow, had the least errors respectively equal to 6.7%, 8.660%, and 13.5%, which can be recommended for the studied area and those with similar hydrological characteristics. On the other hand, hydraulic simulation is also introduced as an efficient method to determine TC which can be used in any desired watershed.

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Gareyev, A. M., I. A. Popelnyuk, and D. M. Stadnik. "Imitation models of aircraft hydraulic units with account for typical faults." VESTNIK of Samara University. Aerospace and Mechanical Engineering 18, no. 1 (April 16, 2019): 30–41. http://dx.doi.org/10.18287/2541-7533-2019-18-1-30-41.

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А method based on comparing oscilloscope patterns of operational parameters with reference curves is one of the most promising methods of diagnosing hydraulic systems among the existing ones. Its implementation does not allow accurate localization of the faulty unit in the system and quantitative estimation of the magnitude of the fault. To eliminate these shortcomings, it is advisable to use simulation models of hydraulic units, taking into account typical faults of a hydraulic system. Their use makes it possible to evaluate the effect of a particular malfunction on the change of dynamic parameters at the stage of mathematical modeling. As a result of the analysis of statistical information and literary sources, characteristic faults of hydraulic systems are identified. Their causes and the impact on the operation of hydraulic units are examined. Simulation models of units taking into account typical faults are described in the Matlab / Simscape software package. They are implemented using a typical hydraulic system as an example. Dynamic characteristics of a hydraulic system in a healthy condition and those of a system with one of the characteristic faults are compared.

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Dmitriev, Dmitry S., and Alexander A. Uchevatkin. "Mathematical simulation in the system of safety monitoring of hydraulic structures and automated control systems of stress-strain state." Vestnik MGSU, no. 12 (December 2021): 1582–91. http://dx.doi.org/10.22227/1997-0935.2021.12.1582-1591.

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Introduction. The article describes the features of the systems for monitoring the safety of hydraulic structures, which are based on the apparatus of mathematical and computer modeling. Prospects for the use of automated control systems for the stress-strain state of building structures of hydraulic structures are considered. Materials and methods. An analytical review of foreign examples of the implementation of monitoring systems for high-pressure hydraulic structures based on mathematical models is presented. The results of computational studies of the Zagorsk PSPP complex within the framework of the hardware and software complex for safety monitoring are shown. The concept of automated stress-strain state control systems is described. Results. The advantages and limitations of widely used, domestic and foreign automated information and diagnostic systems are outlined. On specific examples of the integration of numerical models of hydraulic structures into integrated systems for monitoring the safety of hydraulic structures, methods of expanding the capabilities of monitoring systems in terms of analyzing the stress-strain state of structures and predictive estimates are demonstrated. Insufficient elaboration of the issues of management of the stress-strain state of structures is noted, but the need to develop special structural elements with variable parameters to influence the stress-strain state of hydraulic structures is substantiated. Conclusions. The data presented in the article confirm the need to develop systems for monitoring the safety of hydraulic structures based on complex, multiphysics mathematical models, which can significantly expand the functionality of monitoring systems and, as a result, improve the safety of hydraulic structures. The analysis of world experience indicates the growing lag of the Russian hydropower industry in terms of the integration of mathematical models into the safety monitoring systems for hydraulic structures, which obviously requires additional research and practical work in this area.

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Ren, Ziqiang, Feng Zhou, Hai Zhu, Peihao Zhang, Jiawang Chen, Peng Zhou, Lieyu Tian, Chunhu Liu, and Xiaochao Zhang. "Analysis and Research on Mobile Drilling Rig for Deep Seabed Shallow Strata." Marine Technology Society Journal 55, no. 2 (March 1, 2021): 81–93. http://dx.doi.org/10.4031/mtsj.55.2.7.

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Abstract Drilling rigs for deep seabed shallow strata are commonly used to explore ocean cobalt-rich crust resources and other fields. This paper mainly presents the structure and mechanism of a mobile drilling rig for use in acquiring seafloor cores that are up to 1.5 m in length. The software Simcenter Amesim is used to establish the mobile drilling rig's hydraulic propulsion system model, which is the basis and a core part of the rig. Moreover, closed-loop and PID (proportion-integral-differential) control methods are separately used to control the hydraulic propulsion system for simulation analysis. Comparison of the simulation results shows that the PID control method is more convincing in verifying the design rationality of the hydraulic propulsion system. In the simulation of the PID-controlled hydraulic propulsion system, the co-simulation technology of Simcenter Amesim and MATLAB/Simulink not only establishes the hydraulic and control models but also determines the relevant simulation parameters, thereby helping improve system simulation efficiency. In its verification deployment in the South China Sea, the mobile drilling rig has been operated many times at different depths, and some cores have been successfully obtained. It was also used during the 55th Voyage of China Oceanic Scientific Expedition, which was supported by the China Ocean Mineral Resources R&D Association. Several sites were explored, and a large number of cobalt-rich crust cores were obtained. Theory and sea trials are explained to support further research on the survey of abyssal resources.

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Li, Wending, and Guanglin Shi. "Redundancy management strategy for electro-hydraulic actuators based on intelligent algorithms." Advances in Mechanical Engineering 12, no. 6 (June 2020): 168781402093045. http://dx.doi.org/10.1177/1687814020930455.

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This paper explores three methods for electro-hydraulic actuator redundancy management strategies based on fuzzy aggregation, Mamdani’s fuzzy logic rules, and fuzzy neural network theory. These intelligent management schemes and implementation strategies are studied for a designed hardware-independent redundancy loop. Fault identification and isolation and system reconstruction are performed by combining fuzzy clustering with Mamdani’s fuzzy control, a fuzzy neural network, and redundancy management. Simulation analyses of the three algorithms are performed and loop simulation models are established based on the analysis algorithm. The methods proposed in this paper can solve the problem of misjudgment encountered in traditional methods and can also avoid uncertain states in the system.

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Zhao, Guo Hua, and Jian Guo Chen. "Applications Research on the Synchronization Control of Multi Hydraulic Cylinders of Dump Truck." Applied Mechanics and Materials 220-223 (November 2012): 1653–56. http://dx.doi.org/10.4028/www.scientific.net/amm.220-223.1653.

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Abstract: In this article, a three-hydraulic-cylinders synchronization control model of the hydraulic system of a large dump truck is discussed and the proportional integral (PI) control is used for the hydraulic system. Simulation and performances comparison between the improved and unimproved system have been done by using MATLAB 7.10. To meet different practical engineering requirements, different control methods are designed and selected，aiming to the practical purpose.

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Na, Qi, Guosheng Feng, and Tixian Tian. "Real-Time Leak Detection in High Frequency Hydraulic Cylinder Based on Intelligent Control." Wireless Communications and Mobile Computing 2022 (September 25, 2022): 1–8. http://dx.doi.org/10.1155/2022/4753328.

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Most of the existing hydraulic cylinder internal leakage detection methods are laboratory testing methods, mainly the pressure-holding method, measurement of hydraulic cylinder settlement method, and measuring cup measurement method. The internal leakage of the hydraulic cylinder affects the damping characteristics of the control system. Therefore, real-time internal leakage detection plays an important role in the control characteristics. This paper first proposes a wavelet analysis-based extraction of hydraulic cylinder internal leakage fault eigenvalues for analysis, that is, data processing. A convolutional neural network-based detection method is also proposed, in which the pressure signal of a chamber of a hydraulic cylinder is first obtained through simulation under four operating conditions: no leakage, small leakage, medium leakage, and large leakage. Compared to traditional modelling methods, the method overcomes the difficulties in modelling nonlinear hydraulic systems, requires only pressure signal acquisition, is simple and reliable, and is compared with traditional BP neural networks to demonstrate its superiority.

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Damjanac, Branko, and Peter Cundall. "Application of distinct element methods to simulation of hydraulic fracturing in naturally fractured reservoirs." Computers and Geotechnics 71 (January 2016): 283–94. http://dx.doi.org/10.1016/j.compgeo.2015.06.007.

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Shanmugam, Mohanasundaram, G. Suresh Kumar, Balaji Narasimhan, and Sangam Shrestha. "Effective saturation-based weighting for interblock hydraulic conductivity in unsaturated zone soil water flow modelling using one-dimensional vertical finite-difference model." Journal of Hydroinformatics 22, no. 2 (December 9, 2019): 423–39. http://dx.doi.org/10.2166/hydro.2019.239.

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Abstract Richards equation is solved for soil water flow modeling in the unsaturated zone continuum. Interblock hydraulic conductivities, while solving for Richards equation, are estimated by some sort of averaging process based on upstream and downstream nodes hydraulic conductivity values. The accuracy of the interblock hydraulic conductivity estimation methods mainly depends on the distance between two adjacent discretized nodes. In general, the accuracy of the numerical solution of the Richards equation decreases as nodal grid discretization increases. Conventional interblock hydraulic conductivity estimation methods are mostly mere approximation approaches while the Darcian-based interblock hydraulic conductivities involve complex calculations and require intensive computation under different flow regimes. Therefore, in this study, we proposed an effective saturation-based weighting approach in the soil hydraulic curve functions for estimating interblock hydraulic conductivity using a one-dimensional vertical finite-difference model which provides a parametric basis for interblock hydraulic conductivity estimation while reducing complexity in the calculation and computational processes. Furthermore, we compared four test case simulation results from different interblock hydraulic conductivity methods with the reference solutions. The comparison results show that the proposed method performance in terms of percentage reduction in root mean square and mean absolute error over other methods compared in this study were 59.5 and 60%, respectively.

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Zhang, Yun Long, Si Qing Zhang, Dong Wang, and Dan Li. "Projective Modeling of Hydraulic Turbine Draft Tube Elbow Part Based on Pro/E." Applied Mechanics and Materials 700 (December 2014): 647–50. http://dx.doi.org/10.4028/www.scientific.net/amm.700.647.

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According to the CFD numerical simulation of hydraulic turbine internal flow and simulation calculation of vortex and cavitation of draft tube, and in the three dimensional modeling and analysis of the draft tube elbow is found that commonly modeling methods are tedious process, there is more deviations, not conducive to modify the part size and flow over a smooth. This article proposes a projective modeling method to avoid some drawbacks of traditional methods; the modeling process is convenient and concise, easy to modify the local size, flow more smoothly, and achieve more accurate simulation process.

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Shafiqul Islam, Md, and Abid Hossain Khan. "Thermal-hydraulic analysis of fuel rod of a TRIGA Mark II research reactor." International Journal of Engineering & Technology 9, no. 1 (January 23, 2020): 69. http://dx.doi.org/10.14419/ijet.v9i1.30035.

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In this work, the feasibility of employing “Single Flow Channel Analysis” technique for obtaining the thermal-hydraulic behavior of a TRIGA Mark II research reactor has been studied. Two different simulation methods have been investigated for this purpose; one in which there is no variation in volumetric heat generation along the fuel axis and the other in which there is variation. A hot rod factor of 1.70 has been taken. Results obtained from simulation methods have been compared with both theoretical results and experimental data provided by the manufacturers. Results show that data generated from both simulation methods are more accurate compared to theoretical calculations. Also, the simulation method exempting variation of heat generation has predicted maximum temperature of the fuel centerline just above 750 oC, which is sufficiently accurate. However, temperatures obtained at different axial and radial locations are not close to the experimental values. On the other hand, the simulation technique in which variation of heat generation exists has been able to provide temperature profiles inside the fuel rod and cladding surface almost identical to the experimental values. However, temperature profile of the fuel outer surface is found to be quite different from experimental values.

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Gong, Xun, Xinhua Ma, Yuyang Liu, and Guanfang Li. "Advances in Hydraulic Fracture Propagation Research in Shale Reservoirs." Minerals 12, no. 11 (November 12, 2022): 1438. http://dx.doi.org/10.3390/min12111438.

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The characterization of artificial fracture propagation law in the fracturing process of shale reservoirs is the basis for evaluating the fracture conductivity and a key indicator of the reservoir stimulated effect. In order to improve the fracture stimulated volume of shale reservoirs, this paper systematically discusses the current status of research on artificial fracture propagation law from the research methods and main control factors and provides an outlook on its future development direction. The analysis finds that the study of fracture propagation law by using indoor physical simulation experiments has the advantages of simple operation and intuitive image, and the introduction of auxiliary technologies such as acoustic emission monitoring and CT scanning into indoor physical model experiments can correct the experimental results so as to better reveal the propagation mechanism of artificial fractures. At present, the numerical simulation methods commonly used to study the propagation law of artificial fractures include the finite element method, extended finite element method, discrete element method, boundary element method and phase field method, etc. The models established based on these numerical simulation methods have their own advantages and applicability, so the numerical algorithms can be integrated and the numerical methods selected to model and solve the different characteristics of the propagation law of artificial fractures in different regions at different times can greatly improve the accuracy of the model solution and better characterize the propagation law of artificial fractures. The propagation law of artificial fracture in the fracturing process is mainly influenced by geological factors and engineering factors, so when conducting research, geological factors should be taken as the basis, and through detailed study of geological factors, the selection of the fracturing process can be guided and engineering influencing factors can be optimized.

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Journal articles on the topic 'Hydraulic servomechanisms Simulation methods'

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