# TOTAL FLOW AREA (TFA) FOR DRILLING BITS JET NOZZLES

## TOTAL FLOW AREA (TFA) FOR DRILLING BITS JET NOZZLES DEFINITION, CALCULATIONS, CALCULATOR AND MOBILE APPLICATION

### Introduction To Drilling Bit Jet Nozzles Total Flow Area

#### What Is The Drilling Bit Jet Nozzles?

The part of the bit that includes a hole or opening for drilling fluid to exit. The hole is usually small (around 0.25 in. in diameter) and the pressure of the fluid inside the bit is usually high, leading to a high exit velocity through the nozzles that creates a high-velocity jet below the nozzles. This high-velocity jet of fluid cleans both the bit teeth and the bottom of the hole. The sizes of the nozzles are usually measured in 1/32-in. increments (although some are recorded in millimeters), are always reported in "thirty-seconds" of size (i.e., fractional denominators are not reduced), and usually range from 6/32 to 32/32.

#### Why This Drilling bit jet Nozzles are necessary?

Drilling fluids circulate through a drill string to nozzles at the bit and back to the surface via the system annulus. They provide three crucial functions to drilling:
• Cleaning of the cutting structure.
• Cuttings removal from the hole bottom.
• Efficient cuttings evacuation to the surface.

### What is The Definition Of Total Flow Area (TFA) ?

Total Flow Area (TFA) is a term related to drilling bits jet nozzles which can be defined as the  summation of all the areas of the drilling bit jet nozzles areas which fluid can go through while circulating .

### How To Calculate Drilling bits Total Flow Area (TFA) ?

So it is simple all you have to do is to count all the drilling bit jet nozzles. Accordingly, you can determine flow area with a simple equation.
D is diameter in inch,  Area in square inch

But we have to take in our consideration that diameter of the drilling bits jet nozzles is reported on xx/32 inch.

The formula above can be simplified like this.

N is nozzle size in number/32 inch. Area in square inch

### Example on Drilling bits Total Flow Area (TFA) Calculations

For Example, a drilling bit ahs 5 jet nozzles. 3 x 10/32 in & 2 x 12/32in . To calculate  the total flow area (TFA) of the drilling bit, we will use this equation for each nozzle size and then make a summation for all of them.

Total Flow Area = ( 10^2 +10^2 +10^2 + 12^2+ 12^2 ) / 1303.8
So solving above equation we will have 0.451 inch2

### Bit Nozzles Total Flow Area Spreadsheet

This drilling software/ spreadsheet calculates the total flow area for a selection of up to 11 nozzle sizes.