dynamic modelling of the swash plate of a hydraulic axial piston pump for condition monitoring applications

Abstract In the last years Prognostic and Health Management (PHM) has become one of the challenging topic in the engineering field. In particular, model-based approach for diagnostic relies on the development of a mathematical model of the system representing its flawless status. Once the model has been developed and carefully calibrated on experimental data referred to flawless pump condition the comparison between the model output and the real system output leads to the residual analysis, which gives a diagnosis of the component health. This paper presents the mathematical model of a hydraulic axial piston pump developed in order to replicate the dynamic behavior of the swash plate for PHM applications. The model has been developed on the basis of simplified hypotheses, a friction model between swash plate and bearings has been introduced. A detailed experimental activity was carried out to calibrate and validate the model with step tests and sweep tests. The comparison between numerical and experimental results shows a satisfying agreement and highlights the model capability to reproduce the swash plate dynamics. Future works will include tests with the pump in faulty conditions to evaluate the pump health state through the residual analysis of the swash plate position

Design and testing of orifice valves for use in freight railcars hydraulic suspension system

The work presented in this thesis describes the specific steps undertaken to design and test two spool type control valves that will be part of Amsted Rail’s innovative vertical hydraulic damper system. The design challenge lies in the requirement that these spool valves must maintain a linear relation between pressure drop, flow rate, and position, during the extension and retraction cycles of the hydraulic damper. To this end, a series of laboratory experiments were conducted on spools having different land geometries in order to acquire the optimum apertures that will produce the desired performance based on simulation data provided by Amsted Rail. The effect of the working fluid temperature on the performance of the two designed spool valves was also investigated. Experimental testing was successful in identifying two spool valves that meet the provided design criteria within 2% for AW46 hydraulic oil working fluid at a temperature of 25°C (77°F)

Investigation of spool-type solenoid operated hydraulic directional control valves

The integrated approach of engineering systems analysis enables one to outline a systematic method of solution of a number of engineering problems. The investigation of the problem usually starts with the definition of a physical model of the system on the basis of a set of requirements; the system can be some equipment like a valve or a pump. The physical model is normally much too complex to be investigated directly, therefore, through assumptions it is simplified to an abstract model. From the abstract model, again via assumptions, a mathematical model is derived which combines the separate subsystems (mechanical, hydraulic, etc.,) into an integrated network of ideal network elements. Network topology enables the investigator to obtain a set of independent equations which can then be solved. In parallel with the analytical work tests on the physical model are carried out to compare the accuracy of the analysis and, hence, to make suitable adjustments in the theory. The knowledge gained from the exercise just described is used with other considerations for the design of a new or improved product. This is the approach which has been adopted in this thesis to the analysis of a hydraulic, solenoid-actuated, four-port, directional-control valve. The experimental work was restricted to the operation of the valve with fluid flow through two ports only, further to Fig. 1.1 the hydraulic supply was connected to port P and port A to tank. This meant that the fluid was passing through a single orifice without flowing into an external load such as a hydraulic motor. This is in accordance with the definition of the system under investigation discussed later. The complete system was simulated by means of digital and analogue computers, and in addition, programmes have been suggested to make suitable design changes in the valve

Volume 2 – Conference: Wednesday, March 9

10. Internationales Fluidtechnisches Kolloquium:Group 1 | 2: Novel System Structures Group 3 | 5: Pumps Group 4: Thermal Behaviour Group 6: Industrial Hydraulic

Numerical Heat Transfer and Fluid Flow 2021

This reprint focuses on experiments, modellings, and simulations of heat transfer and fluid flow. Flowing media comprise single- or two-phase fluids that can be both compressible and incompressible. The reprint presents unique experiments and solutions to problems of scientific and industrial relevance in the transportation of natural resources, technical devices, industrial processes, etc. In the presented works, the formulated physical and mathematical models together with their boundary and initial conditions and numerical computation methods for constitutive equations lead to solutions for selected examples in engineering

Erosion Degradation Characteristics of a Linear Electro-Hydrostatic Actuator Under a High-Frequency Turbulent Flow Field

The paper proposes a performance degradation analysis model based on dynamic erosion wear for a novel Linear Electro-Hydrostatic Actuator (LEHA). Rather than the traditional statistical methods based on degradation data, the method proposed in this paper firstly analyzes the dominant progressive failure mode of the LEHA based on the working principle and working conditions of the LEHA. The Computational Fluid Dynamics (CFD) method, combining the turbulent theory and the micro erosion principle, is used to establish an erosion model of the rectification mechanism. The erosion rates for different port openings, under a time-varying flow field, are obtained. The piecewise linearization method is applied to update the concentration of contaminated particles within the LEHA, in order to gain insight into the erosion degradation process at various stages of degradation. The main contribution of the proposed model is the application of the dynamic concentration of contamination particles in erosion analysis of Electro-Hydraulic Servo Valves (EHSVs), throttle valves, spool valves, and needle valves. The effects of system parameters and working conditions on component wear are analyzed by simulations. The results of the proposed model match the expected degradation process. (C) 2017 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics