Mass Flow Rate Formula

What is Mass Flow Rate?

This can thus be described as the mass of a certain substance that passes across a particular area in a defined period. In simple terms, it is the rate at which mass is flowing and, as a unit, is usually measured in kg/s.

This concept is essential in many fields, including engineering and environmental science, since it enables us to understand and calculate the behavior of fluids in a variety of systems such as in pipes, channels or airflows. For example, knowledge of the mass flow rate can be used in designing transport systems with the efficiency of transporting liquid and gases or in evaluating the dispersion of pollutants in the environment.

Formula

The mass flow is expressed as given by,

m=ρVA

Where,  

• ρ = density of fluid,

• V = velocity of the liquid, and 

• A = area of cross-section

Solved Example

Example: For a given fluid find the mass flow rate whose density is 800 kg/m3, velocity, and area of cross-section is 30 m/s and 20 cm2 respectively.

Solution:   

Given values are,

ρ = 800 kg/m3

V = 30 m/s and

A = 20 cm2

  = 0.20 m2

Given formula is,

m = ρVA 

Here, ρ = 800

V = 30

A = 0.20

Given the velocity, the mass flow rate shall be,

m = 800 × 30 × 0.20 

m = 4800 kg/s

Understanding mass flow rate helps one predict how fluids behave in any given scenario; therefore, it is one of the fundamental concepts of fluid mechanics.