Studying the Dynamics of Miniature in-Pipe Vibration Type Robots

2018 ◽  
Vol 19 (6) ◽  
pp. 396-401 ◽  
Author(s):  
V. G. Gradetsky ◽  
◽  
V. G. Chashchukhin ◽  
Keyword(s):  
Author(s):  
Wenjie Bai ◽  
Quan Duan ◽  
Zaoxiao Zhang

Hydraulic tests for elongated orifice-induced wall pressure fluctuations and vibration in pipeline have been carried out. The regulating modes of test system consist of maintaining outlet pressure to increase flow rate and maintaining flow rate to decrease outlet pressure. Both regulating modes would increase the possibility of cavitation within elongated orifice, which has been confirmed by numerical simulation in present study. Statistical characteristics of the fluctuating pressure and structure vibration response have been studied. The standard deviation analyses indicate that the amplitude of fluctuating pressure is mainly determined by flow rate. The power spectral density analyses show that the energy of the fluctuating pressure behind elongated orifice is concentrated in lower frequency range and it can be divided into two parts in this test: the pressure pulsation excited by plunger pump and the random fluctuating pressure produced by elongated orifice’s disturbance. The power spectral density of pipe vibration response shows that the lower frequency of pipe vibration response can be ascribed to the fluctuating pressure behind elongated orifice and the characteristic frequencies corresponding to cavitation within elongated orifice are in the higher frequency range.


2012 ◽  
Vol 626 ◽  
pp. 993-996
Author(s):  
N. Liyana Tajul Lile ◽  
M.J. Hasnul ◽  
R.A. Siregar ◽  
J.C. Leong

Circular pipes are widely used to convey goods to a desired location. Flow inside a pipe needs to be smoothed and unobstructed to ensure an optimize flow of particle. However, pipes are prone to clogging or blocking due to deposition of unwanted impurities and external objects. Built up inside a circular pipe will affect the flow velocity and pressure within the pipe. This paper presents a method of assessing blockage inside a pipe by using vibration analysis. The effect of blockage was observed through changes in pipe vibration response and also turbulence intensity. The changes in vibration parameters were identified together with the reduction of flow area due to increasing blockage size.


Author(s):  
Thomas Shurtz ◽  
Daniel Maynes ◽  
Jonathan Blotter

This paper presents an approach using numerical simulations that have been used to characterize pipe vibration resulting from fully developed turbulent flow in a straight pipe. The vibration levels as indicated by; pipe surface displacement, velocity, and acceleration are characterized in terms of the influences of geometric and material properties of the pipe, and the effects of varying flow velocity, fluid density and viscosity have considered Reynold’s numbers ranging from 9.1×104 – 1.14×106. A large eddy simulation fluid model was coupled with a finite element structural model to simulate the fluid structure interaction using both one-way and two-way coupled techniques. The one-way technique passes the spatially and temporally varying wall pressure from a completed flow solution with fixed wall boundaries to the structural model. The structural model is then solved for wall displacements. The two-way technique involves the additional passing of wall displacement back to the fluid model which is then resolved given the new boundary location. The structural and fluid models are thus continually updated until convergence is reached at each time step. The results indicate a strong nearly quadratic dependence of pipe wall displacement on fluid average velocity. This relationship has also been verified in experimental investigations of pipe vibration. The results also indicate the pipe vibration has a power law type dependence on several variables. Dependencies on investigated variables are non-dimensionalized and assembled to develop a functional relationship that characterizes turbulence induced pipe vibration.


2017 ◽  
Vol 263 ◽  
pp. 733-736 ◽  
Author(s):  
P. Dunst ◽  
T. Hemsel ◽  
W. Sextro

Tribologia ◽  
2017 ◽  
Vol 272 (2) ◽  
pp. 49-58 ◽  
Author(s):  
Wacław GAWĘDZKI ◽  
Jerzy TARNOWSKI

The article presents the influence of friction force values during the contact of a gas pipeline with sand pack on the transmission of soil vibrations on a tested pipe section. Field experiments were carried out on standard gas pipeline insulations subjected to dynamic interactions. The load sources comprised artificially generated soil vibrations with an impulsive character. Within the course of experiments, soil and pipe vibration acceleration signals were registered for different values of friction forces in its contact with the soil. The value of friction forces being a variable parameter during experiments were applied by the change of values of the tension static force of the gas pipeline section. The analysis of the registered soil and pipe vibration acceleration signals were conducted based on the time-domain signal decomposition method, Hilbert-Huang Transform (HHT). This method enables one to decompose the non-stationary vibration acceleration signal into narrowband components. For each component, a course of instantaneous values for frequency and amplitude was specified. The dependence of the pipe vibration acceleration amplitude on the pipe tensile force and friction force of the pipe in the contact with the soil was demonstrated.


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