Effect of Blockage Size on Pipe Vibration

2012 ◽  
Vol 626 ◽  
pp. 993-996
Author(s):  
N. Liyana Tajul Lile ◽  
M.J. Hasnul ◽  
R.A. Siregar ◽  
J.C. Leong
Keyword(s):  
Flow Velocity ◽  
Turbulence Intensity ◽  
Vibration Analysis ◽  
Vibration Response ◽  
Circular Pipe ◽  
Flow Area ◽  
Circular Pipes ◽  
External Objects ◽  
Vibration Parameters ◽  
Pipe Vibration

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.

Vibration Analysis of Blocked Circular Pipe Flow

2012 ◽  
Vol 165 ◽  
pp. 197-201 ◽  
Author(s):  
N. Liyana Tajul Lile ◽  
Hasnul Hadi ◽  
M.R. Roslan
Keyword(s):  
Fluid Flow ◽  
Pipe Flow ◽  
Vibration Analysis ◽  
Vibration Measurement ◽  
Circular Pipe ◽  
Foreign Objects ◽  
Circular Pipe Flow ◽  
Vibration Parameters ◽  
Almost All ◽  
The Impact

Pipes are found in almost all buildings and constructions where they are used to convey fluid to a desired location. Liquid containing foreign objects and impurities will sometimes creates unintentional built up or clog obstruction along the interior surface of the pipeline. This phenomenon may affect the fluid flow within the pipe. This work analyzed the impact of different blockage sizes inside a clear Polyvinyl Chloride (PVC) circular pipe using vibration measurement. Observations were made on the fluid flow patterns during the flow. This work encompasses the correlation between blockage thickness inside a circular pipe and vibration parameters.

Vibration Analysis of a Screw Pump Unit

2013 ◽  
Vol 753-755 ◽  
pp. 1727-1730
Author(s):  
Yue Zhang ◽  
You Hong Xiao ◽  
Jun Weng ◽  
Wan You Li
Keyword(s):  
Mathematical Method ◽  
Vibration Analysis ◽  
Vibration Spectrum ◽  
Vibration Response ◽  
Fe Model ◽  
Force Response ◽  
Pump Unit ◽  
Surface Integral ◽  
Screw Pump

In this paper, the vibration of a three screw pump was studied. Firstly the vibration response of the pump was tested. Then the FE model of the pump was constructed and the modals of it were calculated. The exactness of the result was confirmed by the testing modals and the reasonable of the FE model was verified at the same time. Finally, the force acted on rotors due to pressure was calculated by the mathematical method of surface integral. The force was loaded on the FE model and the force response was predicted, which represented the basic vibration of the screw pump. Based on the work above, the vibration spectrum of the screw pump was analyzed.

Numerical and Experimental Studies of Pipe Vibration Generated by Elongated Orifice

2016 ◽  
Author(s):  
Wenjie Bai ◽  
Quan Duan ◽  
Zaoxiao Zhang
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Flow Rate ◽  
Vibration Response ◽  
Frequency Range ◽  
Fluctuating Pressure ◽  
Outlet Pressure ◽  
Wall Pressure Fluctuations ◽  
Power Spectral ◽  
Pipe Vibration

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.

Computerized Model of Transition in Circular Pipe Flows: Part 1 — Experimental Definition of the Problem

1999 ◽  
Author(s):  
Hidesada Kanda
Keyword(s):  
Reynolds Number ◽  
Turbulent Flow ◽  
Critical Reynolds Number ◽  
Natural Disturbance ◽  
Reynolds Numbers ◽  
Entrance Region ◽  
Circular Pipe ◽  
Experimental Investigations ◽  
Circular Pipes ◽  
Definition Of

Abstract A conceptual model was constructed for the problem of determining in circular pipes the conditions under which the transition from laminar to turbulent flow occurs, so that it becomes possible to calculate the minimum critical Reynolds number. Up until now this problem has been investigated by stability theory with disturbances at the pipe inlet. However, the minimum critical Reynolds number has not yet been obtained theoretically. Hence, the author took up the problem directly from many previous experimental investigations and found that (i) plots of the transition length versus the Reynolds number show that the transition occurs in the entrance region under the condition of a natural disturbance, and (ii) plots of the critical Reynolds number versus the ratio of bellmouth diameter to the pipe diamter show that with larger shapes of bellmouths, laminar flow will persist to higher Reynolds numbers. The problem is thus defined clearly as: Under the condition of an ordinary disturbance, the transition from laminar to turbulent flow occurs in the entrance region of a straight circular pipe, then the Reynolds number takes a minimum value of about 2000.

scholarly journals Discharge Estimation Using Tsallis and Shannon Entropy Theory in Natural Channels

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1786
Author(s):  
Jitendra Kumar Vyas ◽  
Muthiah Perumal ◽  
Tommaso Moramarco
Keyword(s):  
Flow Velocity ◽  
Surface Flow ◽  
Tsallis Entropy ◽  
Accurate Estimation ◽  
Mean Flow ◽  
Flow Area ◽  
Cross Sectional ◽  
The Cross ◽  
Discharge Estimation ◽  
Mean Flow Velocity

Streamflow measurements during high floods is a challenge for which the World Meteorological Organization fosters the development of innovative technologies for achieving an accurate estimation of the discharge. The use of non-contact sensors for monitoring surface flow velocities is of interest to turn these observed values into a cross-sectional mean flow velocity, and subsequently, into discharge if bathymetry is given. In this context, several techniques are available for the estimation of mean flow velocity, starting from observed surface velocities. Among them, the entropy-based methodology for river discharge assessment is often applied by leveraging the theoretical entropic principles of Shannon and Tsallis, both of which link the maximum flow velocity measured at a vertical of the flow area, named the y-axis, and the cross-sectional mean flow velocity at a river site. This study investigates the performance of the two different entropic approaches in estimating the mean flow velocity, starting from the maximum surface flow velocity sampled at the y-axis. A velocity dataset consisting of 70 events of measurements collected at two gauged stations with different geometric and hydraulic characteristics on the Po and Tiber Rivers in Italy was used for the analysis. The comparative evaluation of the velocity distribution observed at the y-axis of all 70 events of measurement was closely reproduced using both the Shannon and Tsallis entropy approaches. Accurate values in terms of the cross-sectional mean flow velocity and discharge were obtained with average errors not exceeding 10%, demonstrating that the Shannon and Tsallis entropy concepts were equally efficient for discharge estimation in any flow conditions.

Vibration Analysis of Masonry Structures due to Blasting Construction of Mountain Tunnels

2012 ◽  
Vol 170-173 ◽  
pp. 3116-3120
Author(s):  
Tao Wang ◽  
Zhong Qiang Fang ◽  
Hao Li
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Vibration Analysis ◽  
Element Model ◽  
Vibration Response ◽  
Blasting Vibration ◽  
Masonry Structures ◽  
Safety Standard ◽  
Construction Quality ◽  
Mountain Tunnels

Blasting construction of Houyuntai Mountain tunnels has vibration influence on ground masonry structures. 3-D finite element model is established to analyze this problem which indicates the house’s vibration response velocity induced by blasting loads. According to this analysis, the structure range of removal and strengthening is assured based on the allowable safety standard of 0.02~0.025m/s of blasting vibration. They include that the houses in 20m range of both sides of horizontal tunnel axis should be removed; the security in 20~28m range is not good, as a result the houses should be removed or strengthened; and the security over 28m range is good for houses. Moreover, some factors such as construction quality can influence houses’ anti-vibration safety.

G802 Torsion Effect on the Flow Velocity and Turbulence in Helical Circular Pipes(2)

2007 ◽  
Vol 2007 (0) ◽  
pp. _G802-1_-_G802-4_
Author(s):  
Yasutaka HAYAMIZU ◽  
Shinitirou YANASE ◽  
Toru HYAKUTAKE ◽  
Toru SHINOHARA ◽  
Toshiya NODA ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Circular Pipes ◽  
Torsion Effect

Effetti dell'ipocapnia e dell'ipercapnia sul flusso liquorale acqueduttale e sul flusso ematico nel seno sagittale superiore. Studio quantitativo con Cine-RM contrasto di fase in soggetti normali

1997 ◽  
Vol 10 (2_suppl) ◽  
pp. 43-45
Author(s):  
M. Santoni ◽  
M. Mascalchi ◽  
M. Cellerini ◽  
A. Cuttano ◽  
G. Dal Pozzo
Keyword(s):  
Flow Velocity ◽  
Cardiac Cycle ◽  
Mean Flow ◽  
Csf Flow ◽  
Flow Area ◽  
Sagittal Sinus ◽  
Cine Mr ◽  
Plastic Bag ◽  
The Mean ◽  
Hydrodynamic Equilibrium

The aqueductal CSF and superior sagittal sinus (SSS) blood flow were quantified in 9 healthy volunteers using a Phase Contrast Cine MR technique with retrospective cardiac gating and velocity of encoding of 10 and 30 cm/s. All subjects were examined in basal conditions, during hypocapnia determined by sustained hyperventilation and during hypercapnia (>5%) obtained with rebreathing in a plastic bag. In basal conditions, the aqueductal CSF flow area showed a mean increase of 24% synchronous with the cerebral systole, whereas variations of the SSS flow area during the cardiac cycle were negligible (>9%). The mean flow velocity and volume in the SSS were 11.7 cm/s and 236 ml/min. Mean peak systolic and diastolic aqueductal CSF velocity were + 2 cm/s and −2 cm/s. Hypocapnia determined in all but one subjects a decrease of the SSS blood and aqueductal CSF velocities. During hypocapnia a decrease of the aqueductal CSF flow area was also observed. Hypercapnia was associated with a decrease of the SSS flow velocity in 3 subjects and to minor changes in the remaining 6 subjects. Hypercapnia determined an increase (up to 30%) in the peak systolic and diastolic aqueductal CSF flow velocity in 3 subjects, negligible changes in 5 subjects and a decrease of the same parameters in one subject. The aqueductal CSF flow area was decreased in 8 subjects during hypercapnia. Hypocapnia and hypercapnia are relatively simple tests which can be used to modify the intracranial hydrodynamic equilibrium in healthy subjects. Further investigations are however needed before their application to the study of intracranial hydrodynamics in patients with hydrocephalus.

Efficiency Comparison Between Circular and Semicircular Fins Circumscribing Circular Pipes

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
R. Chakraborty ◽  
A. Sirkar
Keyword(s):  
Temperature Distribution ◽  
Thermal Performance ◽  
Numerical Results ◽  
Circular Pipe ◽  
Two Dimensional ◽  
Governing Equations ◽  
Degree Polynomial ◽  
Circular Pipes ◽  
Efficiency Comparison ◽  
Detailed Derivation

A new design of fin has been conceived, which is in the shape of a semicircular strip. A step-by-step straightforward detailed derivation of the governing equations for two-dimensional temperature distribution in a semicircular fin has been presented, assuming a third degree polynomial. Numerical results are presented to illustrate the effects of pipe size and the number of semicircular fins on the thermal performance of the fin. It has been shown mathematically that the efficiency of a semicircular fin can be greater than that of a circular fin, having same total volume of fin material when employed over the circumference of a circular pipe.

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