Incompressible pulsating flow for low Reynolds numbers in orifice plates

Reis, Mara Nilza Estanislau; Hanriot, Sérgio de Morais

doi:10.1016/j.flowmeasinst.2017.01.001

Cited by 22 publications

(5 citation statements)

References 31 publications

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“…Variations in C d were observed to increase with amplitude of pulsation, but could not be correlated to any particular variable, e.g., Strouhal number. Similar variations in pulsating C d have been reported by Reis and Hanriot (2017), very recently for low Reynolds number pulsating liquid flow. Deviation of C d from steady state values in accelerating and de-accelerating flows have been studied as early as 1951 (Daily et al, 1955).…”

Section: Background Motivation and Existing Literaturesupporting

confidence: 88%

Measurement and Prediction of Discharge Coefficients in Highly Compressible Pulsating Flows to Improve EGR Flow Estimation and Modeling of Engine Flows

Brahma

2019

Front. Mech. Eng.

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An assumption of constant discharge coefficient (C d) is often made when modeling highly compressible pulsating engine flows through valves or other restrictions. Similarly, orifices and flow-nozzles used for real-time EGR flow estimation are often calibrated at a few steady-state points with one single constant C d that minimizes the error over the selected points. This quasi-steady assumption is based on asymptotically constant C d observed at high Reynolds number for steady (non-pulsating) flow. It has been shown in this work that this assumption is not accurate for pulsating flow, particularly at large amplitudes and low flow rates. The discharge coefficient of a square-edged orifice placed in the exhaust stream of a diesel engine produced C d 's varying between 0.60 and 0.90 for critical/near-critical flows. A novel pulsating flow measurement apparatus that allowed independent variation of pressure, flow rate and frequency and allowed reproducible measurements independent of transducer characteristics, produced C d 's in the range of 0.25-0.60 with a similar square-edge orifice. The variation in C d was found to be correlated to two dimensionless variables, η and ξ , defined as the standard deviation of the pulsating pressure signal, σ p , normalized by ρV 2 and p across the orifice, respectively. The results suggest that many aspects of compressible pulsating flow through flow restrictions are yet to be understood.

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Section: Background Motivation and Existing Literaturesupporting

confidence: 88%

Measurement and Prediction of Discharge Coefficients in Highly Compressible Pulsating Flows to Improve EGR Flow Estimation and Modeling of Engine Flows

Brahma

2019

Front. Mech. Eng.

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“…Considering that the largest number of failures is associated with valves of compressor cylinders of the first stage, an experimental assessment of their efficiency and tightness is necessary, which is one of the mandatory steps in the process of checking the safety of a compressor unit [8,9].…”

Section: Engineeringmentioning

confidence: 99%

Methodology of Experimental Investigations of Valve Operation

Seyidahmadov¹

2019

EUREKA: Physics and Engineering

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Tightness, as well as the reliability of the valve plate, is a complex property of the effective operation of compressor cylinders of the first stage and, in general, gas-engine reciprocating compressors. The issue of valve plate tightness is a subject of independent study, since technical and economic efficiency depends on their work. In this connection, only some data obtained under operating conditions are presented in this work. As a research result, it is found that, taking into account the identified requirements for the gas lift system, in order to effectively increase the operating hours of valves with increased tightness of the plate, it is necessary to check and purge the valves. Therefore, each valve in the gas lift compressor station, without subjecting them to cleaning, is first recommended to check for leaks. To confirm the feasibility of checking valve tightness, special equipment is offered for each gas-lift compressor station, a purge chamber, on which the tightness of valve plates is checked. The usefulness and importance of the purge chamber is in preparation of the valve at the gas lift compressor station, which contributes to increased efficiency, safe operation, normal tightness and reliability of its operation.

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“…They proposed a simple pulsating flow model for orifice flowmeter, which can reduce the sampling error by making a reasonable choice of the averaging time. Reis et al [7] (2017). studied the effect of pulsation variation and time inertia of incompressible pulsating flow at low Reynolds number on the outflow coefficient of an orifice flowmeter.…”

Section: Introductionmentioning

confidence: 99%

Dynamic characteristics of orifice flowmeter impulse response based on CFD simulation

Xiang¹,

Guo²,

Song³

et al. 2023

Proceedings of the 19th International Flow Measurement Conference 2022 on Flow Measurement - FLOMEKO 2022

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Because of its simple structure and ability to measure in reverse, orifice flowmeters are widely used in petroleum, chemical and other fields. In the measurement, the pipeline flow state instability occurs, which has a greater impact on the measurement performance of the orifice flowmeter. In order to study the influence of dynamic flow on the dynamic characteristics of orifice flowmeter. Based on CFD simulation, the dynamic characteristics of orifice flowmeter with different throttling ratio (β) under sinusoidal pulsating flow conditions is studied. Through the simulation of the internal flow field of the orifice flowmeter under the conditions of 7 different frequencies and 4 different amplitude combinations, the differential pressure values under different working conditions are extracted to analyze the amplitude-frequency characteristics and phase-frequency characteristics. The results show that the frequency has a great influence on the dynamic characteristics of the orifice flowmeter. At the throttling ratio is 0.2, the flow rate is 6 m 3 /h and the amplitude is 1.2m³/h, the orifice flowmeter amplitude-frequency characteristic linearity is as low as 1.9860%, phase difference is as low as -7.56°.

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Incompressible pulsating flow for low Reynolds numbers in orifice plates

Cited by 22 publications

References 31 publications

Measurement and Prediction of Discharge Coefficients in Highly Compressible Pulsating Flows to Improve EGR Flow Estimation and Modeling of Engine Flows

Measurement and Prediction of Discharge Coefficients in Highly Compressible Pulsating Flows to Improve EGR Flow Estimation and Modeling of Engine Flows

Methodology of Experimental Investigations of Valve Operation

Dynamic characteristics of orifice flowmeter impulse response based on CFD simulation

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