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.
For ideal piston flows, if the required ACH is infinitely high and the air supply and exhaust locations can be exchanged at the end of each half hour, the CO ppm rise distribution in the first half hour would be the same as that in Figure 1 and it would be reversed in the second half hour, as shown in Figure 1 Half hour half cycle or 1 h a full cycle chosen here corresponds to the half hour and 1 h CO ppm rise criteria in the Australian standard AS 1668.
It is generally accepted that an increased fraction of piston flow leads to a higher probability of inclusion removal.
However, gas injection seems (Figure 6) to decrease the fraction of piston flow.
2) For all combinations of flow, position and dimensions of the porous plug, a reduction of the piston flow fraction resulted in comparison to a tundish without gas injection system.
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:
w], the tracer is said to have moved as piston flow (Jury et al.
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).
For ideal piston flows, if the required ACH is infinitely high and the air supply and exhaust locations can be exchanged at the end of each half hour, the CO ppm rise distribution in the first half hour would be the same as that in Figure 1and it would be reversed in the second half hour, as shown in Figure 1 Half hour half cycle or 1 h a full cycle chosen here corresponds to the half hour and 1 h CO ppm rise criteria in the Australian standard AS 1668.
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.