Expansion losses

Neglect expansion loss at entrance to tank, since it will be so small. 

The consideration of the pressure drop over the monoliths containing a variety of CPSI (cells per in ) for the modeling of honeycomb reactor may be required, since Ap of the reactor strongly depends on CPSI of monolith. Eqn. (7) for the pressure drop of the honeycomb was employed to develop the reactor model describing the performance of the honeycomb fabricated in the present work [8]. and Ke indicate contraction and expansion loss coefficient at the honeycomb inlet and outlet, respectively and o is the ratio of free flow area to frontal area. 

The pressure drop due the contraction and expansion losses through the ports in the plates must be added to the friction loss. Kumar (1984) suggests adding 1.3 velocity heads per pass, based on the velocity through the ports. 

Still-gauging methods are adequate for only the largest leaks. The accuracy of most tank-installed liquid level gauges is usually /s in. at best. A product loss reflected by a 0.062-in. level drop for a 100-ft-diameter tank translates to a 306 gal/day leak. If this Vi6-in. drop in product level is not discernible from the masking effects of fluid expansion, losses in excess of 2650 barrels annually will go undetected. At, for example, 20 per barrel, this loss amounts to over 53,000 for a single tank. Most importantly, the associated liability risks of groundwater contamination could involve much greater potential costs. 

Fig. 27. Contraction/expansion losses coefficient f vs. open area fraction for different cell densities and soot mass loadings.

Tubular proliferation of the tonoplast, and hydration of middle lamella and wall matrix material, began 7-14 days after petal fall. This hydration of the wall was associated with increasing aqueous extractability of wall poly(glycosiduronic acids), which became extreme during ripening that followed cessation of cell expansion. Loss of galactosyl and arabinosyl residues from the wall also became marked after cell expansion had ceased, and incorporation of D-[uC]glucose into wall polysaccharides ceased, but incorporation of L-[uC]proline into wall protein continued. 

Construct the dry-pressure-drop line on log-log coordinates (optional). For turbulent flow, the gas-phase pressure drop for frictional loss, contraction and expansion loss, and directional change loss are all proportional to the square of the superficial F factor. For the dry packing the pressure drop can be calculated from the equation... 

The correlation presented in Fig. 12-6 was developed by Leibson et al.12 on the basis of a formula for C0 obtained by adding the contraction loss from point i to point o of Fig. PI2-1 to the expansion loss from point o to point d. Equations for the contraction loss APJpL and the expansion loss APe/p, are available in standard texts and handbooks on fluid flow. The expressions used are as follows... 

Use Eq. (5.68). There is no final expansion loss, since the stream does not expand upon discharge, and == 0. From Eq. (5.66), since is very large, = 0.4. Hence... 

An expansion loss can also be minimized by substituting a conical expander for the flanges shown in Fig. 5.13. The angle between the diverging walls of the... 

Contraction-loss coefficient, dimensionless Expansion-loss coefficient, dimensionless Loss factor for fitting or valve, dimensionless Flow consistency index, kg/m-s -" or lb/ft-s " ... 

This equation is an inverted form of the core pressure drop in Eq. 17.65. For the isothermal pressure drop data, p, = p = l/(l/p)m. The friction factor thus determined includes the effects of skin friction, form drag, and local flow contraction and expansion losses, if any, within the core. Tests are repeated with different flow rates on the unknown side to cover the desired range of the Reynolds number. The experimental uncertainty in the/factor is usually within 5 percent when Ap is measured accurately within 1 percent. 

Ke Expansion loss coefficient for flow at heat exchanger exit (Eq. 17.65 and Fig. 

This is 1 percent of the 761bf/in previously calculated. In this example the pipe was long (several thousand feet). If the pipe were short, the contraction and expansion losses would be just as large, but the percentage error in neglecting them would be much greater. 

The friction losses are associated with the flow in a 75 m length of 50 mm pipe including one gate valve, one globe valve, two short curvature elbows, a contraction (at A) and an expansion at B. At this stage, neglecting the contraction and expansion losses, one can express the loss term in terms of the unknown velocity V as ... 

The F term for frictional losses includes the following (1) contraction loss at tank exit, (2) friction in the straight pipe, (3) friction in the two elbows, and (4) expansion loss at the tank entrance. 

Let subscript 1 refer to the bypass subscript 4 refer to bypassed section From Eq, (5.73), since 2 - Z, and fittings losses and contraction and expansion losses are neglected/... 

Extruded PE nets are useful for orchards, farms, and vineyards to exclude birds and stop the expansive loss they can inflict on crops. Spaces in the nets are large enough to allow bees to pass and keep shade to a minimum. 

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