A study on vibration control of the engine body for a large scale diesel engine using the semi-active controlled hydraulic type of top bracing

Emission and fuel consumption in swirl-supported diesel engines strongly depend on the in-cylinder turbulent flows. But the physical effects of squish flow on the tangential flow and turbulence production are still far from well understood. To identify the effects of squish flow, Particle image velocimetry (PIV) experiments are performed in a motored optical diesel engine equipped with different bowls. By comparing and associating the large-scale flow and turbulent kinetic energy (k), the main effects of the squish flow are clarified. The effect of squish flow on the turbulence production in the r−θ plane lies in the axial-asymmetry of the annular distribution of radial flow and the deviation between the ensemble-averaged swirl field and rigid body swirl field. Larger squish flow could promote the swirl center to move to the cylinder axis and reduce the deformation of swirl center, which could decrease the axial-asymmetry of annular distribution of radial flow, further, that results in a lower turbulence production of the shear stress. Moreover, larger squish flow increases the radial fluctuation velocity which makes a similar contribution to k with the tangential component. The understanding of the squish flow and its correlations with tangential flow and turbulence obtained in this study is beneficial to design and optimize the in-cylinder turbulent flow.

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Experimental Study on Wear Monitoring of Marine Diesel Engine’s Piston Ring by Magnetoresistive Sensor

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.424-425.132 ◽

2012 ◽

Vol 424-425 ◽

pp. 132-136

Author(s):

Guo Jin Chen ◽

Zhang Ming Peng ◽

Jian Guo Yang ◽

Qiao Ying Huang

Keyword(s):

Diesel Engine ◽

Large Scale ◽

Piston Ring ◽

Test Bed ◽

Operating Modes ◽

Magnetoresistive Sensor ◽

Marine Diesel ◽

Wear Monitoring ◽

Oil Tanker ◽

Test Result

On the diesel engine’s test bed, this paper has studied the parameters regarding the diesel engine’s rotational speed, the piston ring’s width and wearing capacity and so on, and their relation with the output signal of the magnetoresistive sensor under the reverse drawing of the diesel engine. The research discovered that the piston ring’s wear and the magnetoresistive sensor’s output have the corresponding relationship. And on the oil tanker with the 6RTA52U diesel engine, the influence of the diesel engine’s operating parameters and the load situations to the magnetoresistive sensor’s output is surveyed under four kinds of different operating modes. The test result and the research conclusion provide the technical foundation for the online Wear monitoring of the large-scale marine diesel engine’s piston ring.

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Active Vibration Control of a Triple Flexible Structures Combined With Actuators

Volume 3C: 15th Biennial Conference on Mechanical Vibration and Noise — Vibration Control, Analysis, and Identification ◽

10.1115/detc1995-0598 ◽

1995 ◽

Author(s):

Kazuto Seto ◽

Yoshihiro Toba ◽

Fumio Doi

Keyword(s):

Vibration Control ◽

Large Scale ◽

Active Vibration Control ◽

Flexible Structures ◽

Low Frequency ◽

Tall Buildings ◽

Control Force ◽

Active Vibration ◽

Strong Winds ◽

Lq Control

Abstract In order to realize living comfort of tall buildings by reducing the vibration of higher floors by strong winds, this paper proposes a new method of vibration control for flexible structures with a large scale. The higher a tall building the lower its natural frequency. Since obtaining sufficient force to control the lower frequency vibrations of tall buildings is a difficult task, controlling the vibration of ultra-tall buildings using active dynamic absorbers is nearly impossible. This problem can be overcome by placing actuators between a pair of two or three ultra-tall buildings and using the vibrational force of each building to offset the vibrational movement of its paired mate. Therefore, it is able to obtain enough control force under the low frequency when the proposed method is used. In this paper, a reduced-order model expressed by 2DOF system under taking into consideration for preventing spillover instability is applied to control each flexible structure. The LQ control theory is applied to the design of such a control system. The effectiveness of this method is demonstrated theoretically as well as experimentally.

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Vibration Control and Actuation of Large-Scale Systems

10.1016/c2019-0-02636-2 ◽

2020 ◽

Keyword(s):

Vibration Control ◽

Large Scale ◽

Large Scale Systems

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High-Rise Building Seismic Vibration Control Using Large Tuned Top-Floor Mass Damper

Journal of Disaster Research ◽

10.20965/jdr.2009.p0246 ◽

2009 ◽

Vol 4 (3) ◽

pp. 246-252

Author(s):

Akifumi Makino ◽

Keyword(s):

Reinforced Concrete ◽

Vibration Control ◽

Large Scale ◽

Response Analysis ◽

Strong Wind ◽

Reinforced Concrete Structure ◽

Vibration Period ◽

High Rise ◽

Mass Damper ◽

Story Drift

This paper details the design of a high-rise reinforced concrete building whose top floor is isolated and used as the mass for a large-scale mass damper, describing the effect of the vibration control realized. Conventional mass dampers with additional weight at the building tops have been installed to improve environmental vibration against strong wind. Mass dampers have rarely been used, however, as measure against earthquakes. We developed large-scale vibration control using the top floor building weight to serve as a mass damper. The building is a high-rise reinforced concrete structure, 162 meters high, with 43 above-ground stories. Based on seismic response analysis using artificial earthquake waves, the natural vibration period of the mass damper was tuned to decrease story drift in the entire building. The mass damper reduced maximum story drift angle by 20%.

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Study on the Combustion Noise Characteristic of Low Speed Diesel Engine

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.945-949.750 ◽

2014 ◽

Vol 945-949 ◽

pp. 750-753 ◽

Cited By ~ 1

Author(s):

Li Qi Yan ◽

Hui Jun Ge

Keyword(s):

Diesel Engine ◽

Vibration Control ◽

Combustion Engine ◽

Combustion Noise ◽

Aerodynamic Noise ◽

Power Device ◽

Response Analysis ◽

Cylinder Pressure ◽

Real Condition ◽

Low Speed

In recent years, the Low speed two stroke diesel engines are widely used as the main power device of big ship for its so many advantages such as the high power, better economical efficiency and good maintenance. However, the problem of diesel strong vibration and noise becomes a more and more serious at the same time. Because of the Construction Features of marine two-stroke low-speed diesel engine, the structure has to be suffered different kind of forces when it runs. In considering the source of vibration, the whole noise can be divided into combustion noise、machinery noise and aerodynamic noise. The combustion noise caused by cylinder pressure is the most important part of diesel noise. In this paper, the cylinder pressure curves are tested. The internal combustion engine dynamics and the equivalent node load are used in the calculation procedure to achieve the real condition simulation. The loading program is made to simulate the change of cylinder pressure and the move of piston. The transient response of the diesel engine is calculated. The characteristics of diesel caused by cylinder pressure are analyzed.The response analysis can be used to the vibration control.

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