# Orifices and Nozzles on a Horizontal Plane

Written by Jerry Ratzlaff on . Posted in Flow Instrument

When orifices and nozzles are installed having the piping horizontal and assuming that there is no elevation change, the following equations can be used.

## Orifices and Nozzles on a Horizontal Plane formulas

 $$\large{ Q = C_d \; A_o \; Y \; \sqrt { \frac{ 2 \; \Delta p}{ \rho \; \left( 1\; -\; \beta^4 \right) } } }$$ $$\large{ Q = C_d \; A_o \; Y \; \sqrt { \frac{ 2 \; g \; \Delta h}{ \rho \; \left( 1\; -\; \beta^4 \right) } } }$$ $$\large{ \Delta P = \frac{1}{2} \; \rho \; \left( 1 - \beta^4 \right) \; \left( \frac{ Q }{ C_d \; A_o \; Y } \right)^2 }$$ $$\large{ \Delta h = \frac{1}{2\;g} \; \left( 1 - \beta^4 \right) \; \left( \frac{ Q }{ C_d \; A_o \; Y } \right)^2 }$$

### Where:

$$\large{ Q }$$ = flow rate

$$\large{ \rho }$$  (Greek symbol rho) = density

$$\large{ C_d }$$ = discharge coefficient

$$\large{ \Delta y }$$ = elevation change ( $$\Delta y = y_1 - y_2$$ )

$$\large{ Y }$$ = expansion coefficient (Y = 1 for incompressible flow)

$$\large{ g }$$ = gravitational acceleration

$$\large{ G }$$ = gravitational constant

$$\large{ \Delta h }$$ = head loss

$$\large{ A_o }$$ = orifice area (GOA)

$$\large{ p }$$ = pressure

$$\large{ \Delta p }$$ = pressure differential ( $$\Delta p = p_2 - p_1$$ )

$$\large{ \beta }$$  (Greek symbol beta) = ratio of pipe inside diameter to orifice diameter

### Solve for:

$$\large{ Y = \frac{ C_{d,c} }{ C_{d,i} } }$$

$$\large{ C_{d,c} }$$ = discharge coefficient compressible fluid

$$\large{ C_{d,i} }$$ = discharge coefficient incompressible fluid

$$\large{ \beta }$$  (Greek symbol beta) = $$\frac{d_0}{d_u}$$

$$\large{ d_o }$$ = orifice or nozzle diameter

$$\large{ d_u }$$ = upstream pipe inside diameter from orifice or nozzle