1. Flow Rate Through Tubing
2. Flow Rate Through Tube
3. Flow Rate Through Two Concentric Orifices
4. Flow Rate Through Soil
5. Flow Rate Through Slot Jackpots

This article provides calculation methods for correlating design, flow rate and pressure loss as a fluid passes through a nozzle or orifice. Nozzles and orifices are often used to deliberately reduce pressure, restrict flow or to measure flow rate.

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For instance, if the slot was 1/8' wide the flow rate would likely be less than half of the 1/4', and conversely, if the slot was 1/2' wide the flow rate would likely be greater than doubled. So if anyone can help me out or at least point me in the right direction, it would be much appreciated! Flow through a submerged orifice may be computed by applying Bernoulli’s equation to points 1 and 2 in figure below. Values of C for submerged orifices do not differ greatly from those for nonsubmerged orifices. The flow rate with respect with gap width in general follows a parabolic curve. However, these curves get distorted at lower values of gap opening when the flow starts getting affected due to the minimum gap width restriction. D.The effect of slope angle of the side walls of the hopper on flow rate is very distinct. The rate of flow varies linearly.

In the case of a simple concentric restriction orifice the fluid is accelerated as it passes through the orifice, reaching the maximum velocity a short distance downstream of the orifice itself (the Vena Contracta). The increase in velocity comes at the expense of fluid pressure resulting in low pressures in the Vena Contracta. In extreme cases this may lead to cavitation when the local pressure is less than the vapour pressure of a liquid.

Downstream of the Vena Contracta in the recovery zone, the fluid decelerates converting excess kinetic energy into pressure as it slows. When the fluid has decelerated and returned to the normal bulk flow pattern the final downstream pressure has been reached.

The discharge coefficientcharacterises the relationship between flow rate and pressure loss based on the geometry of a nozzle or orifice. You can find typical values in our article on discharge coefficients for nozzles and orifices.

Standard cubic feet per minute. A measure of air flow at standard conditions, i.e., dry air at 29.92 in. Hg (760 mm Hg) (gauge), 68° F (20° C). Slot Velocity The average velocity of air through a slot. Slot velocity is calculated by dividing the total volume flow rate by the slot area (usually, Vs = 2,000 fpm). Technical Bulletin To Calculate the Amount of Water Flow (GPM) Through Slotted PVC Well Screen First calculate the amount of open area per linear foot: Number/Rows X Slots/Row X Slot Width X Slot Length = Sq.

The relationships for flow rate, pressure loss and head loss through orifices and nozzles are presented in the subsequent section. These relationships all utilise the parameter, the ratio of orifice to pipe diameter which is defined as:

Where the point downstream of the orifice is sufficiently far away that the fluid has returned to normal full pipe velocity profile.

Horizontal Orifices and Nozzles

For orifices and nozzles installed in horizontal pipework where it can be assumed that there is no elevation change, head loss and flow rate may be calculated as follows:

Vertical Orifices and Nozzles

Flow Rate Through Tubing

For orifices and nozzles installed in vertical piping, with elevation change, the following head loss and flow rate equations may be used:

Expansion Coefficient

The expansion coefficient takes account of the difference between the discharge coeffcicient for compressible and incompressible flows. It is defined as:

The expansion factoris typically determined empirically and can be calculated using one of the formulas below.

For incompressible fluids:

American Gas Association method as described in AGA 3.1:

International Standards Organistion method as described in ISO 5167-2:

Orifice Discharge into Free Air

An orifice is an opening with a closed perimeter through which water flows. Orifices may have any shape, although they are usually round, square, or rectangular.
Discharge through a sharp-edged orifice may be calculated from:

Q = Ca?2gh

Flow Rate Through Tube

where
Q= discharge, ft³/s (m³/s)

C =coefficient of discharge

a =area of orifice, ft² (m²)

g =acceleration due to gravity, ft/s² (m/s²)

h =head on horizontal center line of orifice, ft (m)

Flow Rate Through Two Concentric Orifices

The coefficient of discharge C is the product of the coef- ficient of velocity C_v and the coefficient of contraction C_c. The coefficient of velocity is the ratio obtained by dividing the actual velocity at the vena contracta (contraction of the jet discharged) by the theoretical velocity. The theoretical velocity may be calculated by writing Bernoulli’s equation for points 1 and 2.Thus

V₂= ?2gh

The coefficient of contraction C_c is the ratio of the smallest area of the jet, the vena contracta, to the area of the orifice.

Flow Rate Through Soil

Submerged Orifices

Flow through a submerged orifice may be computed by applying Bernoulli’s equation to points 1 and 2 in figure below

Flow Rate Through Slot Jackpots

Values of C for submerged orifices do not differ greatly from those for nonsubmerged orifices.