Effects of pipe elbows and tube bundles on selected types of flowmeters

Mattingly, G. E.; Yeh, Tsyh Tyan

doi:10.1016/0955-5986(91)90050-2

Cited by 62 publications

(14 citation statements)

References 2 publications

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“…Recently questions have arisen about the effect of upstream flow straightener placement upon the discharge coefficient of orifice flowmeters. Work at NIST Boulder (Brennan et al, 1991), NIST Gaithersburg (Mattingly and Yeh, 1991), Southwest Research Institute (Morrow et al, 1991), NOVA HUSKY Research Center (Karnik et al, 1991), and Pacific Gas and Electric Company (Stuart, 1991) have shown that as the flow conditioner is moved along the pipe, the coefficient of discharge begins low when the conditioner (usually a tube bundle) is near the orifice plate. It increases in value passing through the value established by standards and then becoming too large, finally decreases to the correct value as the distance between the tube bundle and the orifice plate becomes very large.…”

Section: Introductionmentioning

confidence: 99%

Mean velocity and turbulence fields inside a β=0.50 orifice flowmeter

et al. 1993

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Section: Introductionmentioning

confidence: 99%

Mean velocity and turbulence fields inside a β=0.50 orifice flowmeter

et al. 1993

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“…The reason for this could be the spacing of the two elbows [1]. The double and single elbow experiments are however different in the range with Reynolds numbers from 10 000 to 40 000.…”

Section: The Double Elbow Experimentsmentioning

confidence: 99%

“…All commonly used flow meter types are to different degrees affected by installation effects. Examples are [1][2][3]. Ultrasonic flow meters are also affected by different flow disturbances.…”

Section: Introductionmentioning

confidence: 99%

Installation effects on an ultrasonic flow meter with implications for self diagnostics

Carlander

Delsing

2000

Flow Measurement and Instrumentation

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A small ultrasonic flow meter for water was exposed to five different test configurations, a reference experiment, a single elbow, a double elbow out of plane, a reduction in pipe diameter and a pulsating flow experiment. All tests were performed in a flow calibration facility ranging over Reynolds number from 25 to 110 000. The experiments with the four installation effects were compared with a reference experiment. The error and the change in standard deviation compared to the reference experiment were calculated. The standard deviation serve as a measure of the noise level of the flow meter. The results show that all disturbances generated errors in the flow measurement. The maximum errors were mainly in the range of 2-4% of flow rate, but at very low flow rates the pulsating flow caused larger errors. In most of the flow range there were no or smaller errors. All installation effects also generated an increase in the noise level. The different pipe configurations increased the standard deviation up to more than 100%. The pulsating flow induced even higher enlargements in the noise level. The errors and the increase in the standard deviation are present in about the same flow ranges. The results demonstrate not only that the installation effects tested introduce errors in the flow measurements but also that these effects can be detected from the noise level in the data. The noise level was determined from the standard deviation. This could be interpreted as that the disturbances amplify the turbulence intensity. Thus the standard deviation can be used as a measure of the turbulence. The presence of a disturbance could be recognised by comparing the magnitude of the noise level in the present data with a reference level valid for the measured flow rate. A procedure like this could possibly be performed by the meter itself in operation.

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“…Recent investigations by Karnik et al (1991), Mattingly and Yeh (1991). Brennan et al (1991), Morrow et al (1991), Gajan et al (1991).…”

Section: Introductionmentioning

confidence: 98%

Slotted orifice flowmeter

et al. 1994

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A new type of obstruction flowmeter has been developed as a "drop-in" replacement for the standard plate in an orifice flowmeter. The replacement consists of radial arrays of slots arranged over the entire surface of the plate. Generalizing the definition of the beta ratio for any obstruction flowmeter as: "slotted orifice" plate which exhibits significantly better operating characteristics. It is less sensitive to upstream flow conditions and has less overall head loss. The ultimate goal is to develop a "drop-in" replacement for standard orifice plates which results in a significantly more accurate meter for minimal investment. P = totalcomparisons between various designs can be made. The value of P for the standard orifice flowmeter using this generalized definition is still the ratio of the orifice diameter to the pipe diameter. Performance for a slotted orifice to a standard orifice have been compared with the plates installed in the same orifice run where various inlet velocity profiles were introduced to simulate poor upstream flow conditioning. The slotted orifice has less overall headloss and less sensitivity to upstream flow conditioning than the standard orifice plate. This results in a flowmeter which is more accurate than the standard orifice flowmeter over a much broader range of operating parameters.A standard orifice plate is one of a variety of obstructiontype flowmeters that can be used to measure the flow rate of a fluid in a pipe. By measuring the pressure drop across such a device, the pressure and temperature upstream of the device, the mass flow rate of the fluid can be determined. In its simplest form, the orifice flowmeter consists of a thin plate, with a hole in the center, that is clamped between pipe flanges. Because geometry is simple, it is low in cost and easy to install or replace. This device is used extensively to measure flows in processing plants, pipelines, water distribution systems, and at well heads. The main disadvantage of the standard orifice plate is its sensitivity to upstream flow conditions. Currently, efforts are under way to better quantify upstream flow conditioning effects on standard orifice flowmeters with the goal of increasing the installed accuracy by an order of magnitude. This work has taken another approach to obtaining the increased accuracy: replacing the standard orifice plate with a

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Effects of pipe elbows and tube bundles on selected types of flowmeters

Cited by 62 publications

References 2 publications

Mean velocity and turbulence fields inside a β=0.50 orifice flowmeter

Mean velocity and turbulence fields inside a β=0.50 orifice flowmeter

Installation effects on an ultrasonic flow meter with implications for self diagnostics

Slotted orifice flowmeter

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