Slugging Pulsating Pressure Source Characteristic & Measurement

Multiphase Slugging Pulsating Pressure Source Characteristic & Measurement   Slugging in multiphase flows can be caused by a variety of factors (see here and here ), including from pigging operations, operational conditions, where low flow velocity cause mixtures to separate (terrain-induced slugging), or low points where liquids at sufficiently high flow flood the low point cross section and cause periodic slugging (also known as riser slugging), as seen in Figure 1. Periodic slugging can be detrimental to piping fatigue, as it causes large pressure pulsations in the system. Currently,...

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Boiler pressure pulsation measurement

A boiler (pressure) pulsation measurement can be made directly by using piezoelectric pressure transducers that are installed into the boiler wall, as seen in Figure 1. Boiler pulsation can also be picked up indirectly using accelerometers placed on the boiler wall, though this setup is limited when compared with the use of pressure transducers, as seen in Figure 2. Comparing the boiler pulsation measurements to known boiler data such as power, gas flow velocity, and so on allows for the assessment of root cause problems such a Vortex Induced Vibration (VIV) on heat exchanger pipes, acoustic...

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Pulsation Measurement

Correctly measuring pulsation is more difficult than it seems. As mentioned elsewhere (Link), Pressure = LinePressure + Kinetic Pressure + Pulsation. Line Pressure (LP) usually is measured without much problem. LP can be affected by Pulsation when long tubing leads to the pressure sensor (see Figure 1). Industry-type pressure sensors tend to be placed on a small bore fitting, often with a blocking valve situated between the pressure sensor and the flange (see Figure 1- flange not shown). This setup works for Line Pressure and suppresses Kinetic Pressure, but is less ideal for pulsation...

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Piping Vibration Physical Mechanisms

The root cause for piping vibration can be one or many of the following: Mechanically-induced vibration Fluctuating Line Pressure (LP) Flow-induced by variations in Kinetic Pressure (KP) Pulsation-driven, i.e. excited by propagating waves in the pipe system Figure 1. Pressure, Line Pressure, Pulsation and %LP. %LP matters for the generation of shock waves from wave steepening, a topic treated elsewhere in this Learn More section. (Click on figure to expand) Mechanically-induced vibration tends to be the largest near a machine or perhaps, externally-induced vibration transmitted e.g. via a...

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Shock Waves from Non-linear Wave Steepening

Wave steepening is a non-linear wave propagation effect that arises for strong pulsation in bubbly liquids, e.g. as is the case for reciprocating pumps and water or oil based mud. Steepening form repetetive shocks and may adversely affect pump equipment and piping fatigue life. To understand this shock generating mechanism, we must first better understand what is implied by the phrase Pressure. There are three pressure components: Line Pressure  (LP) Kinetic Pressure (KP) Pulsation Line Pressure is the stationary part of the pressure, Kinetic Pressure is pressure that moves with the flow...

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