Cone Flowmeter Research Articles

Numerical Investigation of the Cryogenic Cavitating Flow Characteristics in Bi-Directional Cone Flowmeters: A Systematic Parameter Study

As a new type of cone flowmeter, the bi-directional cone flowmeter is a promising device for metering the cryogenic fluid due to its excellent advantages. This work presents a numerical study on the cavitating flow characteristics of liquid nitrogen in the bi-directional cone flowmeters based on a modified cavitation model with thermal effects. The influences of some factors, including operating conditions and structural parameters on the cavitation process and flow characteristics, are clarified. The results show that with the increase in the inlet velocity, the cavitation degree in region III increases, and when the outlet pressure increases, the cavitation degree in region II decreases apparently. Reducing the angle of the front cone can significantly decrease the degree of cavitation in the region II; however, it will strengthen the effects of cavitation on pressure and temperature fluctuation in the region III. As the angle of the rear cone decreases, the cavitation degree in the region III decreases, while the cavitation degree in region II barely changes. The results of this work could present important references for the design and optimization of the bi-directional cone flowmeter for cryogenic engineering.

Flow characteristics of back supported V-cone flowmeter (wafer cone) using PIV

The present experimental study has been carried out to evaluate the performance and flow characteristics of the Wafer cone flowmeter using Particle Image Velocimetry (PIV). Two equivalent diameters (β) of 0.62 and 0.72 with combination of two vertex angles (ϕ) namely 30°and 45°are used for the evaluation of the performance of the flowmeter in the range of Reynolds number of 3 × 103 to 8.19 × 104. The investigation shows that the coefficient of discharge seems to be independent of β-value with the increase in vertex angle. Further, the appropriate location of the downstream pressure tap is also estimated for the cone configuration of β = 0.62 and ϕ = 30°. It is observed that the downstream pressure tap location of 0.8D distance gives a higher value of discharge coefficient compared to 0.0D distance with the error being also lower marginally. PIV data has been analysed for the cone configuration of β = 0.62 and ϕ = 30°at four Reynolds numbers of 3028, 6057, 52755 and 74488 in terms of axial velocity and turbulent intensity. The measurements reveal an interesting phenomenon in terms of the rapid decay of turbulent kinetic energy on the downstream of the cone. This may be due to the interference of the cone wake with the support wake resulting in fast decay. This unique phenomenon leads to the reduction in the requirement of the downstream straight length for the Wafer cone flow meter, unlike other obstruction type flowmeters.

Analysis and optimization of a cone flowmeter performance by means of a numerical and experimental approach

Abstract. Differential pressure flowmeters are commonly used in industrial applications where, however, the upstream flow conditions are usually highly disturbed, caused by the presence, in the network pipe, of elbows, valves, etc. To achieve accurate flow measurements, the use of the cone meter is recommended as the flowmeter has the property to normalize the flow both upstream and downstream. In this paper, the authors present a cone flowmeter of new geometry that allows them to obtain better performance with respect to the original one; in particular, it provides a higher discharge coefficient (Cd) for a wider range of operating conditions.

Shape optimization of the cone body for the improved performance of the V-cone flowmeter: A numerical study

The present study has been carried out to optimize the shape of the cone body by providing a curved surface (the radius of curvature (R)) at the base of the cone element for improving the performance of the V-cone flowmeter using CFD. Radii of curvature of 20 mm (hemispherical, R/d = 0.5), 22 mm (R/d = 0.55) 25 mm (R/d = 0.625) and 27.62 mm (R/d = 0.6905) are taken in order to gradually reduce the arc length keeping the chord length constant. In addition a semi-elliptical based cone with 20 mm semi-major axis and10 mm semi-minor axis has also been investigated in the present study. The centre of the spheres and ellipse lie on the axis either in the frustum or cylindrical part of the cone. The equivalent diameter ratio (β) has been taken as 0.6 while three different fore-vertex angles (φ) namely 60°, 75° and 90° have been investigated. The Reynolds number has been varied in the range of 1 × 103 to 1 × 106. The results have been compared with the slant surface based cone. It is seen that introduction of a curved surface at the cone base has profound effect on the coefficient of discharge of the V-cone flowmeter. The coefficient of discharge is dependent on Reynolds number for the flowmeter with hemispherical and semi-elliptical based cone element. The coefficient of discharge is seen to be a weak function of Reynolds number for Re = 4000 and beyond for the other three curvatures. The cone flowmeter with a curved base cone of R/d equals to 0.55 has higher coefficient of discharge and smaller standard deviation compared to a device with an aft vertex cone.

Influence of cone angle on the performance of a wafer cone flowmeter

The present study explores the effect of upstream disturbances like a single 90°bend, double 90° bends (in plane and out of plane) on the performance of wafer cone flowmeters with same beta ratio (β) of 0.77 but different half cone angles (α) of 30° and 45°. The influence of these disturbances on the upstream and downstream axial velocity (u) profiles are studied experimentally. The orientation effects, if any, are also studied experimentally. The minimum upstream distances required to get a fully developed flow for these disturbances vary with type of upstream disturbance, beta ratio (β) and half cone angle (α) of the wafer cone flowmeter. The study is carried out for a single phase flow with air as working medium at high Reynolds number (ReD = 144000). From the results obtained from this study, it may be concluded that the wafer cone flowmeter with a beta ratio (β) of 0.77 and a cone angle of 30° requires less upstream distance compared to the wafer cone flowmeter with a beta ratio (β) of 0.77 with a cone angle of 45° for all the disturbances under consideration.

Experimental optimization for dual support structures cone flow meters based on cone wake flow field characteristics

Currently, poor safety and processing repeatability are two primary problems that restrict the development of cone flow meters. Cone flow meters with upstream and downstream support structures can improve the safety performance and the level of processing repeatability. For a dual support structures cone flow meter, known as a DSSC, the selection of the downstream support position can greatly affect the discharge coefficient and linearity error below a certain range ratio. Through computational fluid dynamics (CFD) simulation research, the conclusion can be drawn that there exists a large scale vortex ring in the wake field of the cone and that the distribution of the vortex is related to the parameters of the cone. Based on the characteristics of the cone vortex ring, optimizing experiments examining downstream pressure tapping and support structure positions have been designed. The downstream pressure tapping and support positions were obtained for DSSCs with DN100 and β values between 0.45 and 0.65. A set of DSSCs was manufactured according to the conclusions of the optimizing experiments, and performance tests were conducted. The DSSC prototypes had β values ranging from 0.45 to 0.65 and diameters of 50mm, 100mm, and 200mm, respectively. Test results indicate that the discharge coefficient linearity error of DSSC flow meters is smaller than that of V-Cone flow meters. The discharge coefficient uncertainty of DSSCs with different inner tube diameters is 1.27%. The relative discharge coefficient uncertainty of prototypes because of machining consistency is 0.68%.

Study on the design and performance of a bi-directional cone flowmeter

The present study explores a novel design of cone flowmeter for bi-directional flow metering application. Two identical cone shapes are machined with their base circle surfaces joined together with a small step in between them and differential pressure measurement is done across the apex of the cones. The bi-directional cone flowmeter is tested under fully developed flow conditions and its performance under double 90° bend (out-of-plane) is also evaluated. The bi-directional cone flowmeter is tested in a circular pipe (inside diameter of 101mm) with water as the working medium for the flow Reynolds number ranging from 1.18×105 to 5.48×105. Influence of the half cone angle (α) and the location of static pressure taps on the coefficient of discharge (Cd) of a cone flowmeter are studied. Two cones with half cone angles α=30° and α=45° with a constant constriction ratio (β) of 0.75 are studied. Static pressure taps are located on both sides of the bi-directional cone. Two sets of locations of static pressure taps are studied. First set includes two static pressure taps on the pipe wall in the planes of apexes of the bi-directional cone—called apex taps. Second set includes pressure taps on the pipe wall in the planes at a distance D/4 away from the apexes of the bi-directional cone—called D/4 taps. Double 90° bend (out-of-plane) is placed at 1.5D, 5.5D, 9.5D and 13.5D upstream to the bi-directional cone flowmeter. It is observed that the apex static pressure taps located in the plane of apexes of the bi-directional cone result in statistically consistent coefficient of discharge for all Reynolds numbers covered in this study. The results suggest that the bi-directional cone flowmeter is insensitive to the swirl created by double 90° bend (out-of-plane) placed at the upstream of cone flowmeter, if placed at a distance of 9.5D or more.

Research and Design of Air Conditioning Air Flow Test Bench

According to the air flow measurement principle, an automobile conditioner each outlet and atmospheric pressure based on zero characteristics has been developed. The experiment platform adopts V cone flowmeter gas flow indirect measurement of automotive air conditioning of the air outlet pipe, a detailed description of the design of the test bench of mechanical structure, measuring circuit, computer software, through the experimental result analysis, can realize the accurate measurement of air.

Experimental and numerical design of a long-waist cone flow meter

A long-waist cone flow meter is designed for steady differential pressure measurement and relatively small overall pressure drop. A constant-diameter annular flow channel is formed between cone element and pipe wall. The flow field of water flows through cone element is studied with 3-D CFD simulations. The constant-diameter annular channel is found being able to adjust the incoming fluid, and small rear angle of cone element could reduce flow separation and overall pressure difference. An optimized structure of long-waist cone flow meters, referred as LWC, is proposed based on the investigations on flow field analysis. A steady contracting differential pressure and an overall differential pressure can be tapped from a LWC. A set of LWCs was fabricated with diameter ratio β ranging from 0.55 to 0.75, and waist length L from 20 to 60mm when β=0.65 for experimental tests and CFD verifications. A decreasing trend of dimensionless differential pressure Δp* and δp* and an increasing trend of discharge coefficient Cd of LWCs under different Reynolds number are observed and analyzed, and flow rate prediction of different Newtonian single phase flow is experimentally studied. A case study of oil–water two-phase flow is then presented with a selected LWC and an average error below 5% is achieved when treating the mixture a homogeneous flow.

Pressure measurement technique and installation effects on the performance of wafer cone design

The present study explores novel pressure averaging technique for wafer cone flowmeter design and its robustness in the presence of double 90° bend (out-of-plane) and gate valve as a source of upstream flow disturbance. The wafer cone flowmeter is tested in a circular pipe (inside diameter of 101mm) with water as the working medium for the flow Reynolds number ranging from 1.19×105 to 5.82×105. Influence of the half cone angle (α) on the coefficient of discharge (Cd) of wafer cone flowmeter is studied with this new pressure averaging technique. Half cone angles considered in this study are 30° and 45° with a constant constriction ratio (β) of 0.75. The upstream static pressure tap is located at 1D upstream of the wafer cone. The downstream pressure averaging technique comprises eight circumferential holes of diameter 2mm on the maximum diameter step of the wafer cone. The pressure taps are communicated through the support strut which serves as a downstream static pressure tap. The disturbance causing elements are individually placed at 1.5D, 5.5D, 9.5D and 13.5D upstream to the wafer cone flowmeter. The wafer cone flowmeter is also tested with gate valve opening of 25%, 50% and 75% for all the arrangements considered. The 30° cone is found to be better than 45° cone for the range of Reynolds number covered in the present study. The results show that the 30° wafer cone flowmeter with novel downstream pressure averaging technique is insensitive to the swirl flow created by a double 90° bend (out-of-plane) and requires an upstream length of 9.5D with a gate valve as a source of flow disturbance.

Microcontroller-Based Design within the Cone Flowmeter

The flow throttling device for the V-shaped cone-type cutting device, the throttling device to break the traditional flow through the throttling device will shrink to the concept of the pipeline near the central axis, the use of coaxial pipe installed in the V-shaped tip cone contraction of the fluid gradually cutting edge to the inner pipe wall, by measuring the V-shaped inner cone to measure the differential pressure before and after the flow of design ideas. This V-cone flowmeter in a shorter straight pipe conditions, to a wider range than on the clean or dirty fluids to achieve a more accurate and more effective flow measurement. This will be based on single-chip cone flowmeter air mixing systems used in ship gas flow measurements, experimental results show that the SCM-based cone flowmeter has a small size, light weight, high accuracy, easy to use security features .

Experimental Research on the Expansibility Factor Calculation Model of V-Cone Flowmeters

This article aims to improve the accuracy of gas flow measurement of cone flowmeter and get a high-precision expansibility factor calculation model with wide applicable pressure range and different upstream side pressure. The experimental research was based on the DN50 and DN100 two sets of V-Cone flowmeter designed by Tianjin University. As the standard gas flow facility by means of critical flow venturi nozzles was insufficient supply capacity and poor pressure stability in positive pressure method, the experimental data obtained from standard gas flow facility by using negative pressure method was used to fit out the V-Cone flowmeter expansibility factor calculation model --TJU-2012 model. The model was tested with the experimental data obtained from the standard gas flow facility and compared with other four cone flowmeter expansibility factor calculation models, its maximum relative error was better than 0.9% and square averaged root error was better than 0.6%, both of them are the least.

CFD prediction of the effects of the upstream elbow fittings on the performance of cone flowmeters

This paper describes the numerical studies to establish the effect of upstream elbow fittings on the performance of the cone flowmeter. Different combinations of elbows were installed upstream of the cone at a distance of 4D to study their effect on the discharge coefficient of the cone flowmeter. The computational fluid dynamics (CFD) simulations have been conducted with an RNG k – ε turbulence model for three equivalent diameter ratios of the cone flowmeter over a wide range of Reynolds numbers. The elbow fittings have a marginal effect on the discharge coefficients ( C d ) of the cone flowmeters even at very high Reynolds numbers ( Re ∼ O ( 10 6 ) ) . The variation in the discharge coefficients is small (±2%). In addition, the variation in the predicted values of the C d over a wide range of Reynolds numbers is also very small (<1%). The distorted velocity profile due to the elbow fitting at the upstream of the cone is slightly improved in the presence of the cone. The intensity of secondary flows also reduces due to the imposed backflow pressure by the cone. The pressure drop coefficient of the cone flowmeter reduces as 1 / β 4 , and it is independent of the Reynolds number at higher values.

Study on the effect of vertex angle and upstream swirl on the performance characteristics of cone flowmeter using CFD

Computational Fluid Dynamics (CFD) has emerged as a revolutionary tool for optimizing the design of any flowmeter for given conditions. The flow features obtained with CFD are more extensive compared to experiments. In the present study, CFD code ‘FLUENT” after validation has been used to investigate the effect of cone vertex angle and upstream swirl on the performance of cone flowmeter. The values of discharge coefficient ( C d ) evaluated for different vertex angles shows that the value of discharge coefficient is independent of Reynolds number and its value decreases with increase in vertex angle. In the presence of upstream disturbance in the form of swirl, the value of discharge coefficient is also independent of Reynolds number and its value is only marginally affected by the magnitude of swirl. The flow in a longitudinal plane shows the presence of a pair of contra-rotating vortices in the recirculation region just downstream of the cone. The velocity profile downstream becomes stable after a distance of about 5D.

Experimental and CFD study of ventilation flow rate of a Monodraught™ windcatcher

Monodraught™ windcatchers are commercial natural ventilation devices, which are primarily driven by wind to produce both extract and supply air flow. The measurement of the net flow rate (extract minus supply) of a Monodraught™ windcatcher ABS 550 for various wind speeds and directions is introduced. The ventilation measurement system uses a cone flow meter and a blower fan. CFD standard k − ɛ turbulence model is employed to calculate the flow rate. The situation using a blower fan is considered in modelling and the effect of the manometer sensitivity is also discussed. The comparison has indicated a good agreement between measurement and simulation. CFD modelling of the windcatcher is then carried out for the situation of outdoor far field wind. At the same nominal wind speed, the calculated extract flow rate of the windcatcher in a far field wind is roughly twice that for the situation using a blower fan, the wind direction has a small effect on the extract flow rate. The extract and supply flow rates are also calculated for various room pressure due to various wall openings and installation on a flat roof or a pitched roof. The contribution of the buoyancy effect on the flow rates is discussed in simulation.

THE INFLUENCE OF A LIQUID FLOW ON SOUND FIELDS CONFINED BY CONICAL WALLS

Sound propagation in conical waveguides is analyzed for the case where a background flow is maintained through the cone and points along the radial co-ordinate r only. A general expression for the acoustic pressure is derived and the perturbations of the acoustic field accommodated by the presence of a background flow are found by use of the Green function method. In the second part of this paper, flow measurement properties are discussed. The designation of propagation constants such as the wave number and phase speed lose much of their intuitive meaning in a conical waveguide. Instead, the so-called pseudo-guide wave number and pseudo-phase speed are introduced as they are well defined in the cone case and simplifies to the wave number and phase speed in the cylinder case respectively. It is shown that changes due to a background flow in pseudo-guide wave number, pseudo-phase speed, and zero-point crossing times all exhibit an oscillatory behavior as a function of the r co-ordinate. This is in contrast to the case of a cylinder where such changes become a linear function of the distance from the transmitter. The oscillatory behavior in the changes in zero-point crossing times as a function of r does not hamper flow measurement in the cone case since the only requirement to be fulfilled is, in principle, that a one-to-one correspondence between measured output (changes in zero-point crossing times) and actual flow (determined byv0 ) at a specific receiver location exists. It is shown that this requirement is fulfilled as changes in zero-point crossing times depend linearly on the flow coefficient v0at a given r co-ordinate. There are, however, certain discrete r co-ordinate values where this is not the case, namely those where changes in zero-point crossing times become zero for any value of v0. In other words, if the receiver is positioned near r co-ordinates where zero-point crossing times are at a maximum or a minimum for a given value of v0, the truncated cone flow meter sensor is able to measure flow unambiguiosly by detection of changes in zero-point crossing times induced by a background flow.