Orifice equation

Pressure drop across the disperser is calculated by variations of the standard orifice equation ... 

For larger diameter columns, and for low liquid rates, the distributor must be almost exactly level (e.g., within 6 mm for a 3-m diameter) or all pour points will not function. On the other hand, the rises must be high enough to accommodate the backup caused by high liquid rates. The needed head can be estimated from the orifice equation, with a discharge coefficient of 0.5. In some cases the orinces discharge directly into tubes that extend to the packed bed (the Tubed drip-pan distributor ). 

For the highly subcooled subset of Regime 2, ("q, < q ), flow is singlephase (hquid), and integration of Eq. (26-93) gives what is commonly referred to as the orifice equation ... 

So, when q, > q t (low subcooling, flashing before the choke print), use the compressible solution, Eq. (26-95) with q p = q,. Otherwise (for high subcooling, no flashing before the choke point), use the hquid orifice equation, Eq. (26-94). 

Flow of vapor through rupture discs is described using an orifice equation similar to Equation 9-9 but without the additional correction factors. The result is... 

The analysis used by these authors for constant flow conditions has been extended to constant pressure conditions also. The major change arises from the fact that now the flow is a function of the extent to which the bubble has already been formed. This has been introduced into the constant flow equation by means of an orifice equation. 

Q is not a constant in this case it depends on the stage of bubble formation. It can be determined from orifice equation, as... 

In the viscous resistance term in Eq. (163), the radius r can be taken as 1.25 rfb without causing a great loss in accuracy. Equations (162) and (163) reduce to constant flow or constant pressure conditions, respectively, when Q is constant or when it is expressed in terms of orifice equation. 

For gas flow through dry packings, pressure drop may be estimated by use of an orifice equation. For irrigated packings, pressure drop... 

Notched trough distributors (Fig. 14-69g) consist of parallel troughs with side V notches. This distributor obeys the triangular notch equation instead of the orifice equation, which makes the flow proportional to h25 [instead of h05 in Eq. (14-163)]. This high power renders the distributor highly sensitive to out-of-levelness and... 

Although all three forms of the orifice equation will be found in use, the present trend is toward Eq. (10.71) because of the simplified computation. The relation between Cd, C, and K is shown in Fig. 10.10. (The... 

The dry pressure drop across the disperser unit [hd in Eq. (6.41)] is given by a variation of the orifice equation... 

Equation (6.59) was derived from the orifice equation with an orifice coefficient of 0.6 (3), and assuming pure liquid is passing under the downcomer. Tests by Lockett and Gharani (43) showed that Eq. (6.59 gives conservative predictions, even under conditions of significant vapor entrainment in the downcomer underflow (Sec. 6.2.3). 

The two terms on the right-hand side represent the contributions due to viscous and turbulent flow resistances. It was assumed that the pressure drop due to viscous resistance is negligible ky = 0). However, the parametric sensitivity of K on the critical superficial gas velocity was also studied. The turbulent pressure drop was estimated using the orifice equation... 

The recommended sparge ring to impeller diameter ratio is 0.65-0.8, while the ring sparger orifice diameter is in the range of 2-10 mm, and the gas velocity through the orifice is between 15 and 30m/sec. Pressure drop across a perforated disperser or orifice is estimated by the conventional orifice equation ... 

The dry pressure drop calculation is based on the orifice equation for gases, in which the pressure drop is proportional to the square of the vapor velocity through the orifice, and the vapor density. In terms of liquid head, the equation for sieve trays is written as... 

For sieve trays, the simplified orifice equation is used to estimate the pressure loss for flow through ihe holes ... 

For orifice-type distributors, the hand of liquid required to prodnee a given flow through the orifice can be calculated form a dimensional form of [be orifice equation ... 

If the total drop across the perforation is denoted by AP0/pL (where AP0 = APe 4- APc, obtain a formula for C0 of the orifice equation... 

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