Cavitation Erosion in the Portion of an Oil Passage Through Which Bubbles Pass

2017 ◽  
Author(s):  
Kento Kumagai ◽  
Toshiharu Kazama
Keyword(s):  
Hydraulic System ◽  
Cavitation Erosion ◽  
Dynamics Simulation ◽  
Hydraulic Systems ◽  
Computational Fluid Dynamics Simulation ◽  
Construction Machinery ◽  
Cavitation Bubbles ◽  
Experimental Apparatus ◽  
Research Findings ◽  
Pass Through

Cavitation erosion is a serious problem in the hydraulic system of construction machinery. In particular, the erosion which occurs even when cavitation bubbles only pass through oil passages, occurs at a connecting portion between the hydraulic components and piping, and the erosion causes oil leakage, which is a serious problem for hydraulic systems. However, it is difficult to predict the eroded area and to prevent the erosion because of a lack of research findings. The present study investigated erosion in the portion through which cavitation bubbles passes using a basic experimental apparatus that simulates an oil passage of hydraulic components, and by conducting a computational fluid dynamics simulation. The following results were obtained. Erosion occurs near the outlet of the oil passage, cavitation bubbles frequently disappear rapidly near the area of erosion, and the cause of bubble disappearance is the pressure distribution and amplification of the pressure wave of cavitation jets at the outlet of the oil passage. These results help explain the erosion generation mechanism and the characteristics of erosion in oil passages of hydraulic components, and can be used to design methods of reducing erosion.

An Adding Mass Method for Stiffly Mechanical System Simulation and Applications to Construction Machinery

2001 ◽  
Author(s):  
Etsujiro Imanishi ◽  
Satoshi Yonezawa ◽  
Naoki Sugano ◽  
Eiko Hirooka ◽  
Takahiro Kobayashi
Keyword(s):  
Mechanical System ◽  
Dynamic Simulation ◽  
Hydraulic System ◽  
Piecewise Linear ◽  
Hydraulic Systems ◽  
Practical Application ◽  
Construction Machinery ◽  
Linear Elements ◽  
Improvement Method ◽  
And Control

Abstract A characteristic improvement method for dynamic simulation of a stiff mechanical system by adding mass is presented. Hydraulic systems with check valves and control valves on construction machinery exhibit piecewise-linear characteristics for hydraulic flow rate and spool stroke. The proposed improvement method involves no time delay in determining the mass by considering both eigenvalue distortion of the system and time response. This paper shows a practical application to the boom derricking system of a rough terrain crane, and demonstrates that this method is useful for dynamic simulation of hydraulic system including stiff piecewise-linear elements.

The Modeling Analysis and Dynamics Simulation of Load-Sensing Hydraulic Systems

2011 ◽  
Vol 317-319 ◽  
pp. 307-313 ◽  
Author(s):  
Cong Mei Wei ◽  
Jin Yi Lian ◽  
Jing Jie Li
Keyword(s):  
Simulation Model ◽  
Hydraulic System ◽  
Simulation Analysis ◽  
Dynamics Simulation ◽  
Hydraulic Systems ◽  
Load Sensing ◽  
Modeling Analysis ◽  
Analysis System ◽  
Working Device ◽  
The Mathematical Model

This paper analyzes the mathematical model of load-sensing hydraulic system based on power linkage graph method and builds the simulation model AMESim of the system. The load sensitive hydraulic system is applied in the working device of loader, and the simulation model AMESim with ADAMS is built by combining the dynamics analysis system with ADAMS,. The study of simulation on the dynamics is completed under different working conditions and the results of simulation analysis are given.

scholarly journals Comparison of Downdraught and Up Draft Passive Air Conduction Systems (PACS) in a Winery Building

Buildings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 259
Author(s):  
Ádám László Katona ◽  
István Ervin Háber ◽  
István Kistelegdi
Keyword(s):  
Air Conditioning ◽  
Natural Ventilation ◽  
Dynamics Simulation ◽  
Computational Fluid Dynamics Simulation ◽  
General Applicability ◽  
Change Rate ◽  
Air Change Rate ◽  
Simulation Based ◽  
Ventilation Performance ◽  
Air Conduction

A huge portion of energy consumption in buildings comes from heating, ventilation, and air conditioning. Numerous previous works assessed the potential of natural ventilation compared to mechanical ventilation and proved their justification on the field. Nevertheless, it is a major difficulty to collect enough information from the literature to make decisions between different natural ventilation solutions with a given situation and boundary conditions. The current study tests the passive air conduction system (PACS) variations in the design phase of a medium-sized new winery’s cellar and production hall in Villány, Hungary. A computational fluid dynamics simulation based comparative analysis enabled to determine the differences in updraft (UD) and downdraught (DD) PACS, whereby the latter was found to be more efficient. While the DD PACS performed an air change range of 1.02 h−1 to 5.98 h−1, the UD PACS delivered −0.25 h−1 to 12.82 h−1 air change rate. The ventilation performance of the DD version possessed lower amplitudes, but the distribution was more balanced under different wind incident angles, thus this version was chosen for construction. It could be concluded that the DD PACS provides a more general applicability for natural ventilation in moderate climates and in small to medium scale industry hall domains with one in- and one outlet.

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