Flow stream pressure

They are applicable to single-microchannel flow by reducing the appropriate terms. The general relation for flow-stream pressure drop calculations is the following ... 

The model for the pressure drop analysis is depicted in Fig. 9 in which multiple microchannels with an abrupt entrance and exit are shown. The equations to be presented in this section apply to this model and are not restricted to a particular geometry of the microchannel cross-section. They are applicable to single-microchannel flow by reducing the appropriate terms. The general relation for flow-stream pressure drop calculations is the following ... 

Flow-stream pressures. Static pressure is pressing measured perpendicularly to the direction of flow. This is the pressiu-e that one would sense when moving downstream with the fluid. Total pressure is pressiue in the direction of flow, where pressure as a function of direction is at a maximum. Total pressure would be sensed if the stream were brought to rest isentropically. Velocity pressure is the difference between static and total pressure measured at a specific region in the direction of flow. It is called velocity head when measured in height of fluid. Velocity pressure is equal to V2pV, where p is the fluid density and V is the fluid velocity. 

When a pure gas flows through a channel the accompanying fall in pressure is accounted for partly by acceleration of the flowing stream and partly by momentum transfer to the stationary walls. Since a porous medium may be regarded as an assembly of channels, similar considerations apply to flow through porous media, but in the diffusional situations of principal interest here accelerational pressure loss can usually be neglected. If more than one molecular species is present, we are also interested in the relative motions of the different species, so momentum transfers by collisions between different types of molecules are also important. 

Pitot Tubes. The fundamental design of a pitot tube is shown in Eigure 9a. The opening into the flow stream measures the total or stagnation pressure of the stream whereas a wall tap senses static pressure. The velocity at the tip opening, lA can be obtained by the Bernoulli equation ... 

Subsequent to stock preparation and proper dilution, the paper furnish usually is fed to the paper machine through one or more screens or other devices to remove dirt and fiber bundles. It then enters a flow spreader which provides a uniform flowing stream and which is the width of the paper machine. The flow spreader, or manifold, discharges the slurry into a headbox, where fiber flocculation is minimised by microturbulence and where the proper pressure head is provided to cause the slurry to flow at the proper velocity through the slice and onto the moving Fourdrinier wire. 

Rounding of the edge is often employed to ensure absence of a burr. Pressure readings will be high it the tap is inclined upstream, is rounded excessively on the upstream side, has a burr on the downstream side, or has an excessive countersink or recess. Pressure readings will be low if the tap is inclined downstream, is rounded excessively on the downstream side, has a burr on the upstream side, or protrudes into the flow stream. Errors resulting from these faults can be large. 

G = mass flux V = specific volume of stream P = stream pressure f= friction factor D = duct diameter L = flow length g = acceleration due to gravity b = angle of inclination from vertical... 

Another feature of the centrifugal is its ability to admit or extract flow to or from the main flow stream, at relatively close pressure intervals, by means of strategically located nozzles. These flows are referred to as side-... 

Process flow diagrams are more complex and show all main flow streams including valves to enhance the understanding of the process as well as pressures and temperatures on all feed and product lines within all major vessels and in and out of headers and heat exchangers, and points of pressure and temperature control. Also, information on construction materials, pump capacities and pressure heads, compressor horsepower, and vessel design pressures and temperatures are shown when necessary for clarity. In addition, process flow diagrams usually show major components of control loops along with key utilities. 

Process flow diagrams (Figure 3.1.3-2) are more complex. They show all main flow streams, valves, vessels, condensers, heat exchangers, instrument locations, reflux columns, etc. Pressures... 

Figure 1-1 is a block diagram of a production facility that is primarily designed to handle gas wells. The well flow stream may require heating prior to initial separation. Since most gas wells flow at high pressure, a... 

For rupture disk sizing the downstream pressure is assumed to reach the critical flow pressure although the dowm stream pressure initially may be much low er. Under these conditions the flow through the orifice that the disk produces on rupture is considered to be at critical flow. The assumptions of critical pressure do not apply... 

The reduction of the sample was made at 2250 K In a flowing stream of hydrogen carrier gas ( SO cm /mln). The total pressure of the carrier gas was approximately 1 atm. The water vapor produced during the reduction was swept by the carrier gas Into an electrolytic-type (P2O5) moisture monitor and a continuous recorder trace of the water concentration as a function of time was obtained. A typical plot of the moisture content of the carrier gas as a function of time Is shown In Figure 3. The region on the left side of this figure where the moisture content... 

Type Configuration Spiral wound Stream Flow (m Pressure (bar)... 

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