THE FORMALIZATION OF VARIATIONAL PROBLEM MODELING IN THE CURRENT DISTRIBUTION IN THE SAFE OPERATION OF HYDRAULIC SYSTEMS

2016 ◽  
Vol 8 (4) ◽  
pp. 46-49
Author(s):  
Мезенцев ◽  
A. Mezentsev ◽  
Сазонова ◽  
Svetlana Sazonova
Keyword(s):  
Mathematical Models ◽  
Variational Problem ◽  
Current Distribution ◽  
Hydraulic System ◽  
Transient Flow ◽  
Flow Distribution ◽  
Safety Performance ◽  
System Of Equations ◽  
Hydraulic Systems ◽  
Safe Operation

For the calculated area of the hydraulic system is considered a sequence of formation of mathematical models of flow distribution. The solution of the variational problem allows to obtain a system of equations describing the transient flow regime for the protection of objects of management tasks in safety performance.

Methodology Development for Transient Flow Distribution Analysis in High Temperature Gas-Cooled Reactor

2020 ◽  
Author(s):  
Takeshi Aoki ◽  
Hiroyuki Sato ◽  
Hirofumi Ohashi
Keyword(s):  
High Temperature ◽  
Hydraulic System ◽  
System Analysis ◽  
Molecular Diffusion ◽  
Transient Flow ◽  
Flow Distribution ◽  
Distribution Analysis ◽  
Design Improvement ◽  
Air Ingress ◽  
High Temperature Gas

Abstract In the thermal hydraulic design of the prismatic-type of the high temperature gas cooled reactor (HTGR), unintended flows such as gap flows between columns, cross flows between column layers and gap flows between permanent reflectors should be analyzed to minimizing the unintended flows. The flow distribution considering unintended flows in the reactor has been evaluated for steady and conservative condition. On the other hand, the transient thermal hydraulic analysis for satisfactorily realistic conditions will be helpful for the design improvement of prismatic-type HTGR. The present study aims to improve the thermal hydraulic system analysis code developed by Japan Atomic Energy Agency based on the RELAP5/MOD3 code and confirm its applicability for the transient flow distribution analysis for prismatic-type HTGRs during anticipated operational occurrences and accidents for its design improvement utilizing experiences on high temperature engineering test reactor (HTTR) design. The calculation model and code were developed and validated to evaluate the detailed flowrate distribution considering the unintended flows in the core and the molecular diffusion that is important to analyze beginning air ingress behavior in an air ingress accident triggered by a rupture of a primary coolant piping in HTGR. It is concluded that a prospect has confirmed to apply the improved thermal hydraulic system analysis code for transient flow distribution analysis for prismatic-type HTGRs.

Energy Efficient Excavator Hydraulic Systems With Digital Displacement® Pump-Motors and Digital Flow Distribution

2020 ◽  
Author(s):  
Jill Macpherson ◽  
Christopher Williamson ◽  
Matthew Green ◽  
Niall Caldwell
Keyword(s):  
Power Distribution ◽  
Hydraulic System ◽  
Energy Recovery ◽  
Flow Distribution ◽  
Small Scale ◽  
Hydraulic Systems ◽  
System Architectures ◽  
Fuel Savings ◽  
Duty Cycles ◽  
Displacement Pump

Abstract Environmental and economic factors are driving the development of more fuel efficient off-highway vehicles. The pathway to fuel savings of greater than 50% in an excavator application through utilisation of system architectures unlocked by Digital Displacement technology is presented. Pump flow distribution using digital valves instead of traditional proportional control valves is demonstrated experimentally. The “Workbus” power distribution scheme is demonstrated on a small scale backhoe arm on a laboratory test rig. These tests do not include hydraulic energy recovery. A backward-facing simulation of an 18 tonne excavator is described. The simulation uses input data collected from grading and lorry loading duty cycles. Applying the workbus system architecture to the excavator in simulation, fuel savings of 31% to 48% are realized. With the addition of energy recovery capability via Digital Displacement Pump-Motors, simulated fuel savings are 53% to 58% compared to the original excavator hydraulic system.

THE CALCULATION OF THE UNLOADED TRANSMISSION CAPACITY OF THE DESIGNED HYDRAULIC SYSTEM

2016 ◽  
Vol 8 (3) ◽  
pp. 77-81
Author(s):  
Сазонова ◽  
Svetlana Sazonova ◽  
Мезенцев ◽  
A. Mezentsev
Keyword(s):  
Approximation Algorithm ◽  
Hydraulic System ◽  
A Priori ◽  
Transmission Capacity ◽  
System Of Equations ◽  
Hydraulic Systems

For the formation of the unloaded reserve functioning of hydraulic systems can be applied approximation algorithm. Thus it is necessary to ensure the consistency of the system of equations consists in the fact that the number of manageable nodes in the parameters of limited consumption must match the number of bypass lines, the diameters of which are to be determined. Once movement of these lines is not involved in the formalization of ass-Chi, so their rational configuration can be obtained on the basis of the study of a priori given set of options.

THE CALCULATION OF THE LOADED TRANSMISSION CAPACITY OF THE DESIGNED HYDRAULIC SYSTEM

2016 ◽  
Vol 8 (3) ◽  
pp. 64-70
Author(s):  
Мезенцев ◽  
A. Mezentsev ◽  
Сазонова ◽  
Svetlana Sazonova
Keyword(s):  
Iterative Algorithm ◽  
Hydraulic System ◽  
Analytical Calculation ◽  
Flow Distribution ◽  
Transmission Capacity ◽  
System Control ◽  
System Of Equations ◽  
Mode Of Operation ◽  
Functional Reduction ◽  
Nominal Mode

Used approximation conversion method of the system of equations that defines the conditions of extremum for the analytical calculation of the loaded transmission capacity of the designed hydraulic system. Control action in the iterative algorithm is set in the key settings that you previously found limited consumption and hydraulic ha-the characteristics connected subscriber subsystems. Their tuning is performed according to the analysis of the flow distribution in the nominal mode of operation of systems according to the principles of functional reduction.

Soft Switching Approach to Reducing Transition Losses in an On/Off Hydraulic Valve

2009 ◽  
Author(s):  
Michael B. Rannow ◽  
Perry Y. Li
Keyword(s):  
Hydraulic System ◽  
Check Valve ◽  
Fluid Flows ◽  
Soft Switching ◽  
Total System ◽  
System Efficiency ◽  
Hydraulic Systems ◽  
Controlled Systems ◽  
Flow Through ◽  
Hydraulic Valve

A method for significantly reducing the losses associated with an on/off controlled hydraulic system is proposed. There has been a growing interest in the use of on/off valves to control hydraulic systems as a means of improving system efficiency. While on/off valves are efficient when they are fully open or fully closed, a significant amount of energy can be lost in throttling as the valve transitions between the two states. A soft switching approach is proposed as a method of eliminating the majority of these transition losses. The operating principle of soft switching is that fluid can temporarily flow through a check valve or into a small chamber while valve orifices are partially closed. The fluid can then flow out of the chamber once the valve has fully transitioned. Thus, fluid flows through the valve only when it is in its most efficient fully open state. A model of the system is derived and simulated, with results indicating that the soft switching approach can reduce transition and compressibility losses by 79%, and total system losses by 66%. Design equations are also derived. The soft switching approach has the potential to improve the efficiency of on/off controlled systems and is particularly important as switching frequencies are increased. The soft switching approach will also facilitate the use of slower on/off valves for effective on/off control; in simulation, a valve with soft switching matched the efficiency an on/off valve that was 5 times faster.

Dynamic balance analysis of contamination control for hydraulic systems based on dynamic filtration ratio

2016 ◽  
Vol 68 (1) ◽  
pp. 45-51
Author(s):  
Guangying Ma ◽  
Shurong Ning ◽  
Yunlong Hu ◽  
jun Gao
Keyword(s):  
Hydraulic System ◽  
Dynamic Balance ◽  
Contamination Level ◽  
Hydraulic Systems ◽  
Level Control ◽  
Content Type ◽  
Contamination Control ◽  
Precise Control ◽  
Dynamic Filtration ◽  
The Relationship

Purpose – The aim of this study is to establish a dynamic model of the filtration ratio. For the problem that the measured value of the filtration ratio is far less than the theoretical value in the actual hydraulic filtering system, the paper aims to find the relationship between the filtration ratio and the parameters of the hydraulic systems, such as the contamination level and the dirt-holding quantity of the filter. Design/methodology/approach – The paper opted for the method of experimental analysis and simulation to determine the relationship between the filtration ratio and the parameters of the hydraulic system, and established a dynamic filtration ratio model. Findings – The paper provides a preliminary model of dynamic filtration ratio, and the model shows that the filtration ratio is exponentially related to the contamination level and the dirt-holding quantity. Different filters have different influence coefficients. The filtering capacity for a certain particle size and the contamination level control of the filter for different hydraulic systems can be judged according to the dynamic balance equation of hydraulic systems. Originality/value – The paper is useful in the selection of filters and in the precise control of the contamination level of the hydraulic system.

Calculation of a closed hydraulic volumetric system

2021 ◽  
pp. 27-30
Author(s):  
Keyword(s):  
Power Plant ◽  
Wind Power ◽  
Hydraulic System ◽  
Working Fluid ◽  
Wind Power Plant ◽  
Hydraulic Systems ◽  
Hydraulic Motor ◽  
Hydraulic Pump ◽  
Oil Pump ◽  
Selection Of

An algorithm is proposed for calculating a closed volumetric hydraulic pump-hydraulic motor system using the example of the hydraulic system of a wind power plant, based on the calculation of the hydraulic systems of mobile machines. The main characteristics of the system components, the selection of initial data for the calculation, working fluid and diameters of hydraulic lines are analyzed. Keywords: hydraulic system, energy, fluid, oil, pump, motor, renewable energy source, wind power plant, machine. [email protected]

Synchronous Control Characteristics Analysis of Shield Propulsion Hydraulic System Based on Tracking Differentiator and Self-Adaptive Nonlinear PID

2021 ◽  
Author(s):  
Sen Li ◽  
XiaoHua Cao
Keyword(s):  
Pid Control ◽  
Hydraulic System ◽  
Control Method ◽  
Hydraulic Systems ◽  
Fuzzy Pid Control ◽  
Synchronous Control ◽  
Tracking Differentiator ◽  
Characteristics Analysis ◽  
Servo Tracking ◽  
Self Adaptive

Aiming at the low precision problem of multi-cylinder cooperative propulsion control in different regions of shield propulsion hydraulic systems under conditions of large load changes, this paper proposes a tracking differentiator and self-adaptive nonlinear PID (TD-NPID) control method to improve the synchronous control characteristics of shield propulsion hydraulic systems. First, the working principles of shield propulsion hydraulic systems were analyzed, and a mathematical model and TD-NPID controller were developed. Then, a simulation model was developed in AMESim-MATLAB environment, and the synchronous dynamic performances of fuzzy PID control, conventional PID control, and TD-NPID control were compared and analyzed. The results demonstrated that the shield propulsion hydraulic system with TD-NPID control had better servo tracking ability and steady-state performance than the systems with fuzzy or conventional PID control, which verified the feasibility of the application of TD-NPID control for the synchronous control of shield propulsion hydraulic systems.

scholarly journals The Influence of Valve-Pump Weight Ratios on the Dynamic Response of Leaking Valve-Pump Parallel Control Hydraulic Systems

2018 ◽  
Vol 8 (7) ◽  
pp. 1201 ◽  
Author(s):  
Haigang Ding ◽  
Jiyun Zhao ◽  
Gang Cheng ◽  
Steve Wright ◽  
Yufeng Yao
Keyword(s):  
Dynamic Response ◽  
Hydraulic System ◽  
Weight Ratio ◽  
Open Loop ◽  
Hydraulic Systems ◽  
Variable Speed ◽  
Weight Factors ◽  
Wide Range ◽  
Parallel Control ◽  
Valve Control

A new leaking valve-pump parallel control (LVPC) oil hydraulic system is proposed to improve the performance of dynamic response of present variable speed pump control (VSPC) system, which is an oil hydraulic control system with saving energy. In the LVPC, a control valve is operating at leaking status, together with a variable speed pump, to regulate the system flow of hydraulic oil simultaneously. Therefore, the degree of valve control and pump control can be adjusted by regulating the valve-pump weight ratio. The LVPC system design, mathematical model development, system parameter and control performance analysis are carried out systematically followed by an experimental for validation process. Results have shown that after introducing the valve control, the total leakage coefficient increases significantly over a wide range with the operating point and this further increases damping ratios and reduces the velocity stiffness. As the valve-pump weight ratio determines the flow distribution between the valve and the pump and the weight factors of the valve and/or the pump controls determines the response speed of the LVPC system, thus if the weight factors are constrained properly, the LVPC system will eventually have a large synthetic open-loop gain and it will respond faster than the VSPC system. The LVPC will enrich the control schemes of oil hydraulic system and has potential value in application requiring of fast response.

scholarly journals Imitation models of aircraft hydraulic units with account for typical faults

2019 ◽  
Vol 18 (1) ◽  
pp. 30-41
Author(s):  
A. M. Gareyev ◽  
I. A. Popelnyuk ◽  
D. M. Stadnik
Keyword(s):  
Hydraulic System ◽  
Quantitative Estimation ◽  
Simulation Models ◽  
Statistical Information ◽  
Hydraulic Systems ◽  
Operational Parameters ◽  
Accurate Localization ◽  
Literary Sources ◽  
Reference Curves ◽  
The Impact

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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