Investigations on Wave Propagation of the Pressure Pulsation in a Helmholtz-Type Hydraulic Silencer With a Hemispherical Vessel

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Takayoshi Ichiyanagi ◽  
Tetsuya Kuribayashi ◽  
Takao Nishiumi
Keyword(s):  
Wave Propagation ◽  
Resonance Frequency ◽  
Pressure Pulsation ◽  
Lumped Parameter Model ◽  
Design Stage ◽  
Hydraulic Systems ◽  
Lumped Parameter ◽  
Reasonable Cost ◽  
Attenuation Characteristics ◽  
Step Section

The Helmholtz-type hydraulic silencer is one of the most practical silencers for attenuating pressure pulsations in hydraulic systems owing to its simple structure and reasonable cost. Maximum attenuation performance can be attained at the resonance frequency in accordance with the principle of Helmholtz resonance. Therefore, it is extremely important to precisely determine the resonance frequency at the design stage. It was clarified in our previous study that the shape of the volume vessel affects the resonance frequency of the silencer because of the wave propagation of pressure pulsation inside the volume vessel. In this study, the attenuation characteristics and wave propagation in a silencer with a hemispherical vessel are investigated. A mathematical model that takes into account the propagation of a one-dimensional wave in the radial direction of the hemispherical vessel is proposed and compared with the step section approximation model and the classic lumped parameter model. Furthermore, the effectiveness of the theoretical analysis is verified by experiments wherein the dimensional specifications of the vessel and neck are adjusted.

Tuning the hygro-mechanical response of paper-based systems using glycerol

2020 ◽  
pp. 1045389X2094716
Author(s):  
Isaias Cueva-Perez ◽  
Roque Alfredo Osornio-Rios ◽  
Aurelio Dominguez-Gonzalez ◽  
Ion Stiharu ◽  
Angel Perez-Cruz
Keyword(s):  
Dynamic Response ◽  
Resonance Frequency ◽  
Mechanical Response ◽  
Water Solution ◽  
Low Cost ◽  
Mechanical Systems ◽  
Lumped Parameter Model ◽  
Glycerol Water ◽  
Energy Harvesters ◽  
Lumped Parameter

In recent years, the need for portable, low-cost, and eco-friendly devices for testing and monitoring has arisen. Paper-based devices have emerged as a response to these needs due to the properties induced by capillarity, flexibility, disposability, and biodegradability. In this work, the authors explored the possibility of tuning the hygro-mechanical response of paper-based cantilever beams using glycerol. A lumped-parameter model with non-linear stiffness is used to describe the dynamic response of the beams using three parameters. An experimental method based on resonance frequency tests is used to study the influence of glycerol on the dynamic response of four different beam configurations. The obtained results demonstrate that the resonance frequency of paper-based mechanical systems can be easily tuned by the imbibition of a glycerol–water solution. This study could lead to the development of tunable paper-based mechanical systems for specific applications such as energy harvesters and hygro-mechanical-based sensors.

Soft Switching in Switched Inertance Hydraulic Circuits

2016 ◽  
Author(s):  
Alexander C. Yudell ◽  
James D. Van de Ven
Keyword(s):  
High Speed ◽  
Soft Switching ◽  
Power Delivery ◽  
Lumped Parameter Model ◽  
Energy Losses ◽  
Hydraulic Systems ◽  
Zero Voltage Switching ◽  
Lumped Parameter ◽  
Capacitive Element ◽  
Zero Voltage

Switched Inertance Hydraulic Systems (SIHS) use inductive, capacitive, and switching elements to boost or buck a pressure from a source to a load in an ideally lossless manner. Real SIHS circuits suffer a variety of energy losses, with throttling of flow during transitions of the high-speed valve resulting in 44% of overall losses. These throttling energy losses can be mitigated by applying the analog of zero-voltage-switching, a soft switching strategy, adopted from power electronics. In the soft switching circuit, the flow that would otherwise be throttled across the transitioning valve is stored in a capacitive element and bypassed through check valves in parallel with the switching valves. To evaluate the effectiveness of soft switching in a boost converter SIHS, a lumped parameter model was constructed. The model demonstrates that soft switching can improve the efficiency of the circuit up to 42% and extend the power delivery capabilities of the circuit by 76%.

A Resonant Air-Standard Heat Engine

2010 ◽  
Author(s):  
C. Richards ◽  
R. Richards ◽  
H. Bardaweel ◽  
M. Anderson
Keyword(s):  
Resonance Frequency ◽  
Heat Engine ◽  
Lumped Parameter Model ◽  
Local Maxima ◽  
Standard Heat ◽  
At Resonance ◽  
Lumped Parameter ◽  
Piston Assembly

A resonant heat engine in which the piston assembly is replaced by a sealed elastic cavity is modeled and analyzed. A linearized nondimensional lumped-parameter model is derived and used to investigate the factors that control the performance of the engine. The results show that operation at resonance is beneficial. Local maxima in efficiency are encountered at odd multiples of the resonance frequency. Efficiency is enhanced by small damping.

scholarly journals Modelling and Validation of Cavitating Orifice Flow in Hydraulic Systems

2021 ◽  
Vol 13 (13) ◽  
pp. 7239
Author(s):  
Paolo Casoli ◽  
Fabio Scolari ◽  
Massimo Rundo
Keyword(s):  
Lumped Parameter Model ◽  
Hydraulic Systems ◽  
Vena Contracta ◽  
Lumped Parameter ◽  
Lumped Parameter Models ◽  
Orifice Flow ◽  
Computational Fluid Dynamics Cfd ◽  
Set Up ◽  
Cfd Method ◽  
Hydraulic Valves

Cavitation can occur at the inlet of hydraulic pumps or in hydraulic valves; this phenomenon should be always avoided because it can generate abnormal wear and noise in fluid power components. Numerical modeling of the cavitation is widely used in research, and it allows the regions where it occurs more to be predicted. For this reason, two different approaches to the study of gas and vapor cavitation were presented in this paper. In particular, a model was developed using the computational fluid dynamics (CFD) method with particular attention to the dynamic modeling of both gaseous and vapor cavitation. A further lumped parameter model was made, where the fluid density varies as the pressure decreases due to the release of air and the formation of vapor. Furthermore, the lumped parameter model highlights the need to also know the speed of sound in the vena contracta, since it is essential for the correct calculation of the mass flow during vaporization. A test bench for the study of cavitation with an orifice was set up; cavitation was induced by increasing the speed of the fluid on the restricted section thanks to a pump located downstream of the orifice. The experimental data were compared with those predicted by CFD and lumped parameter models.

Design and Modelling of a Cartridge Pressure Amplifier

2019 ◽  
Author(s):  
Barbara Zardin ◽  
Giovanni Cillo ◽  
Peter Zavadinka ◽  
Juraj Hanusovsky ◽  
Massimo Borghi
Keyword(s):  
High Pressure ◽  
Duty Cycle ◽  
Research Work ◽  
Control Valve ◽  
Lumped Parameter Model ◽  
Hydraulic Pressure ◽  
Hydraulic Systems ◽  
Hydraulic Actuator ◽  
Virtual Test ◽  
Lumped Parameter

Abstract This works describes the modelling and simulation of a compact cartridge pressure amplifier for linear actuators, especially designed to fit within the rod of the piston. Hydraulic pressure amplifiers of the cylinder type are appreciated in hydraulic systems where high pressure work is needed, especially for a small part of the overall duty cycle. The use of these boosters allows the designer not to oversize the system, which will perform confining the high pressure operation only on the side of the hydraulic actuator. Starting from a previous research work on the same topic, this work proposes new designs for the cartridge amplifier to explore the influence of the control valve, which is the responsible for the delivering of the fluid to the amplifier. The new designs are discussed and then the results coming from the simulation performed with a lumped parameter model in a virtual test rig are shown. The operation of the amplifier is then applied to a more realistic duty cycle to illustrate and validate its operation.

Dynamic Model for an Automotive Overhead Valve-Gear System

1989 ◽  
Vol 42 (11S) ◽  
pp. S171-S174 ◽  
Author(s):  
J. A. Me´ndez-Adriani
Keyword(s):  
Mathematical Model ◽  
Dynamic Model ◽  
Hybrid Simulation ◽  
Gear System ◽  
Lumped Parameter Model ◽  
Design Stage ◽  
Qualitative Comparison ◽  
Viscous Forces ◽  
Lumped Parameter ◽  
Valve Gear

This research presents a lumped-parameter model, distinct from the ones developed until the present time, easily adaptable for its analog/hybrid simulation, and that combines favorably its simplicity and precision to represent appropriately an automotive valve gear system by means of the inclusion of the hydraulic lifter and of the viscous forces produced by its guide. The checking of this new mathematical model has been accomplished by means of a qualitative comparison with other models previously devised. This model will be useful in the design stage to predict the speed at which the valve jump occurs.

Soft Switching in Switched Inertance Hydraulic Circuits

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Alexander C. Yudell ◽  
James D. Van de Ven
Keyword(s):  
High Speed ◽  
Peak Load ◽  
Soft Switching ◽  
Power Delivery ◽  
Lumped Parameter Model ◽  
Energy Losses ◽  
Hydraulic Systems ◽  
Zero Voltage Switching ◽  
Lumped Parameter ◽  
Capacitive Element

Switched inertance hydraulic systems (SIHS) use inductive, capacitive, and switching elements to boost or “buck” (reduce) a pressure from a source to a load in an ideally lossless manner. Real SIHS circuits suffer a variety of energy losses, with throttling of flow during transitions of the high-speed valve resulting in as much as 44% of overall losses. These throttling energy losses can be mitigated by applying the analog of zero-voltage-switching, a soft switching strategy, adopted from power electronics. In the soft switching circuit, the flow that would otherwise be throttled across the transitioning valve is stored in a capacitive element and bypassed through check valves in parallel with the switching valves. To evaluate the effectiveness of soft switching in a boost converter SIHS, a lumped parameter model was constructed. Simulation demonstrates that soft switching improves the efficiency of the modeled circuit by 42% at peak load power and extends the power delivery capabilities by 77%.

Pressure pulsation in roller pumps: A validated lumped parameter model

2008 ◽  
Vol 30 (9) ◽  
pp. 1149-1158 ◽  
Author(s):  
Francesco Moscato ◽  
Francesco M. Colacino ◽  
Maurizio Arabia ◽  
Guido A. Danieli
Keyword(s):  
Pressure Pulsation ◽  
Lumped Parameter Model ◽  
Lumped Parameter
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