Experimental Study of Turbulence Across the Fractal Orifice Plate

2010 ◽  
Author(s):  
S. M. Muztaba Salim ◽  
Franck C. G. A. Nicolleau ◽  
Stephen B. M. Beck ◽  
Andrzej F. Nowakowski
Keyword(s):  
Experimental Study ◽  
Pressure Drop ◽  
Wind Tunnel ◽  
Orifice Plate ◽  
Flow Structures ◽  
Flow Properties ◽  
Flow Area ◽  
Flow Mixing ◽  
Circular Orifice ◽  
Edge Sharpness

An experimental study of turbulence behind a fractal orifice plate, a variant of classical circular orifice plate, was conducted in a circular wind tunnel. Four fractal orifice plates with iteration levels from zero to three in combination with a classical circular orifice plate, each with equal flow area, were used in the study. Of the two main objectives, the first one was to test the superiority of the proposed fractal orifice plate against the classical one and the second one was to investigate the fractal orifice effect on the flow properties. Across the fractal orifice plate, a decrease in the pressure drop and an increase in the flow mixing is observed making it much more efficient than the classical orifice plate. It was suggested that at each fractal iteration, the added edge sharpness generated finer flow structures and these flow structures were eventually responsible for the improved efficiency.

Experimental Study of Various Porosity of Fractal Flow Conditioner for Orifice Plate Flowmeters

2014 ◽  
Vol 699 ◽  
pp. 915-920 ◽  
Author(s):  
Bukhari Manshoor ◽  
Mohd Fahmi Othman ◽  
Izzuddin Zaman ◽  
Zamani Ngali ◽  
Amir Khalid
Keyword(s):  
Experimental Study ◽  
Pressure Drop ◽  
Mass Flow Rate ◽  
Flow Rate ◽  
Experimental Work ◽  
Discharge Coefficient ◽  
Orifice Plate ◽  
Rate Data ◽  
Plant Industry ◽  
Measure Flow Rate

The plant industry is required to measure flow rate more accurately to meet plant operation and cost accounting objectives. The opposing concern of improving flow meter accuracy is resolved by using flow conditioners. The distance of implementation of flow conditioner upstream of the orifice plate flowmeter is also need to be addressed. Hence, in present study, an analysis of the porosity of fractal flow conditioner towards orifice plate flowmeter’s accuracy and the best distance of fractal flow conditioner upstream of the orifice plate flowmeter was determined. In an experimental work, a different porosity of the fractal flow conditioners were installed with different distance upstream of the orifice plate in conjunction with the different disturbances to assess the effects of these devices on the measurement of the mass flow rate. Data gained for all the plates showed that there is increment of pressure drop and change in discharge coefficient of the orifice with lower β value of fractal flow conditioner. Good comparisons with the previous experimental work demonstrate the fractal flow conditioner can preserve the accuracy of metering up to the level required in the standards.

The aeroacoustics of finite wall-mounted square cylinders

2017 ◽  
Vol 832 ◽  
pp. 287-328 ◽  
Author(s):  
Ric Porteous ◽  
Danielle J. Moreau ◽  
Con J. Doolan
Keyword(s):  
Boundary Layer ◽  
Experimental Study ◽  
Reynolds Number ◽  
Wind Tunnel ◽  
Three Dimensional ◽  
Flow Structures ◽  
Hot Wire ◽  
Radiated Noise ◽  
Aspect Ratios ◽  
Square Cylinders

This paper presents the results of an experimental study that relates the flow structures in the wake of a square finite wall-mounted cylinder with the radiated noise. Acoustic and hot-wire measurements were taken in an anechoic wind tunnel. The cylinder was immersed in a near-zero-pressure gradient boundary layer whose thickness was 130 % of the cylinder width, $W$. Aspect ratios were in the range $0.29\leqslant L/W\leqslant 22.9$ (where $L$ is the cylinder span), and the Reynolds number, based on width, was $1.4\times 10^{4}$. Four shedding regimes were identified, namely R0 ($L/W<2$), RI ($2<L/W<10$), RII ($10<L/W<18$) and RIII ($L/W>18$), with each shedding regime displaying an additional acoustic tone as the aspect ratio was increased. At low aspect ratios (R0 and RI), downwash dominated the wake, creating a highly three-dimensional shedding environment with maximum downwash at $L/W\approx 7$. Looping vortex structures were visualised using a phase eduction technique. The principal core of the loops generated the most noise perpendicular to the cylinder. For higher aspect ratios in RII and RIII, the main noise producing structures consisted of a series of inclined vortex filaments, where the angle of inclination varied between vortex cells.

Computational Simulation for Predicting Flow Through a Belleville Washer Damper Unit

2007 ◽  
Author(s):  
Anil Patel ◽  
Derek Tilley ◽  
Jos Darling
Keyword(s):  
Experimental Study ◽  
Pressure Drop ◽  
Flow Rate ◽  
Fluid Dynamic ◽  
Computational Simulation ◽  
Computational Fluid Dynamic Simulation ◽  
Attractive Alternative ◽  
Flow Area ◽  
Load Bearing ◽  
Wide Range

A Belleville washer can be best described as a non flat washer with a conical shape and a uniform cross section. They are also known as disk springs and as the name suggests they are often utilised for their load bearing capabilities. Due to their compactness along the axis of loading and a wide range of attainable load-deflection characteristics they are an attractive alternative to conventional springs. Though Belleville washers are primarily used for their load bearing capabilities, they can also be used to build a damping device; which in turn can be used as part of a suspension system. The non linear deflection of the spring makes it difficult to predict the resulting pressure-flow characteristic and as a result the damper pack is built either by an experienced operative or by a trial and improvement method. Without an analytical tool to predict the behaviour a designer cannot exploit the full functionality of this type of spring. The intension of this paper is to present research undertaken to develop a correlation which describes the pressure drop required for various flow rates when using Belleville washers as damping elements. Using existing load-deflection theory an initial model was developed to relate load with pressure and deflection with flow area which could be used to estimate flow rate. The solutions from a computer simulation showed similar trends to those found in the experimental study, but they estimated smaller pressure drops for a given flow rate. It was postulated that the exit velocity of the fluid created a region of low pressure which tended to close the opening and thus increase the pressure drop. This hypothesis was examined and confirmed with a computational fluid dynamic simulation and the results were used to modify the existing model. Analysis of the new model showed good agreement with the experimental study.

scholarly journals EXPERIMENTAL DETERMINATION OF THE LEVEL OF INCIPIENT TURBULENCE IN THE WORKING PART OF THE T-1 WIND TUNNEL OF IVAN KOZHEDUB KHARKIV NATIONAL AIR FORCE UNIVERSITY

2021 ◽  
Vol 5 (2) ◽  
pp. 98-102
Author(s):  
Віталій Бездєльний ◽  
Сергій Шевченко ◽  
Ілля Грідасов
Keyword(s):  
Experimental Study ◽  
Pressure Drop ◽  
Wind Tunnel ◽  
Experimental Determination ◽  
Air Force ◽  
Normal Condition ◽  
Aerodynamic Drag ◽  
Experimental Studies ◽  
The Subject

The subject of the article is to determine the level of incipient turbulence in the wind tunnel T-1 which is based on the method of measuring the pressure drop. The purpose is to experimentally determine the level of incipient turbulence in the working part of wind tunnel T-1 of Ivan Kozhedub Kharkiv National Air Force University in preparation for aerodynamic testing of aircraft models. Research methods: the method of pressure drop on the surface of the sphere by drainage. The following results of experimental determination of the level of incipient turbulence in the wind tunnel T-1 were obtained. It is established that the wind tunnel T-1 has a level of incipient turbulence 0,5…0,9 %, which corresponds to the normal condition for further experimental studies. Conclusions. According to the results of studies of the incipient turbulence in the wind tunnel T-1 by the method of pressure drop, the main dependences are obtained, and the incipient turbulence of the flow for the wooden sphere x = 0,9 %, and for the metal sphere x = 0,5 %, is determined. Determining the pressure distribution and aerodynamic drag does not involve measures to balance the aerodynamic scales and their certification, which determines the necessary role in the obtained reliable results of the experimental study, and this favors the drainage method.

Fractality in Turbulence

2011 ◽  
Author(s):  
S. M. Muztaba Salim ◽  
F. Nicolleau
Keyword(s):  
Turbulent Flow ◽  
Time Correlation ◽  
Energy Cascade ◽  
Orifice Plate ◽  
Turbulence Energy ◽  
Flow Area ◽  
Classical Counterpart ◽  
Flow Mixing ◽  
Orifice Flow ◽  
Self Similar

Fractality is, as we introduce it, an attribute relating to any object or system where the existence of self-similar replication of the whole is present in any order and scale. This can be realized in any turbulent flow due to the self-similar flow structures in its energy cascade. This intrinsic natural fractality is dominant in any turbulence energy cascade. In this paper, we report how this natural fractality is affected by a forced fractality externally superimposed on turbulent flow in a circular wind tunnel. The forced fractality was created by a fractal orifice plate. The time correlation and energy spectra showed that the forced fractality excites the natural fractality significantly and increases flow mixing. Simultaneously, we found that the fractal orifice plate is much more efficient than the classical orifice plate with equal flow area in terms of the flow mixing and deemed to be a better orifice flow meter than its classical counterpart.

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