piston flow

piston flow

[′pis·tən ‚flō]
(fluid mechanics)
Two-phase (vapor-liquid) flow in which the gas flows as large plugs; occurs for gas superficial velocities from about 2 to 30 feet per second (60 to 900 centimeters per second). Also known as plug flow; slug flow.
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Consequently, if a high ACH is required and the ventilation can be designed to be close to a piston flow in a car park, the PRESEV strategy may have the potential to significantly reduce the ventilation flow rate requirement and the related energy use for CO dilution.
He includes updates material on elementary reactions in ideal reactors, multiple reactions in batch reactors, isothermal piston flow reactors, stirred tanks and reactor combinations, thermal effects and energy balances, design and optimization studies, rate data and thermal dynamics, real tubular or reactors in laminar flow, turbulent tubes, heterogeneous catalysis, multi phase reactors, biochemical reaction engineering, polymer reaction engineering, unsteady reactors, residence time distributions, and reactor designs.
The average downward movement of a solute front, if piston flow happens, can be estimated by the pore-water velocity:
If a conservative tracer such as [Br.sup.-] is transported continuously throughout the soil profile at the same rate as the pore-water velocity [v.sub.w], the tracer is said to have moved as piston flow (Jury et al.
whether the mean convective movement of a solute can be described by piston flow. If the transport of [Br.sup.-] in the soil solution is like a piston displacing fluid, then the pore water velocity, [v.sub.w], will be the velocity of movement of [Br.sup.-].
Several researchers have reported that water and solutes do not move through the root zone by simple piston flow but bypass a large fraction of soil matrix and move rapidly through macropores (Beven and Germann 1982; Jabro et al.
As a result, they move faster and farther in the soil than expected based only on piston flow (Quisenberry and Phillips, 1978).
Oil is pumped into one side of the unit and displaced oil in front of the piston flows freely back to the tank; maximum injection rate is based on the hydraulic pump capacity.