A Venturi Tube and Pressure Drop Calculation in an Automobile Carburetor

Theory of Venturi Tube and Pressure Drop Calculation

A Venturi tube is a device that measures the flow rate of fluid in a pipe. It consists of a pipe with a constricted section, which causes a pressure drop in the fluid passing through it. In some cases, a Venturi tube may be used as the inlet to an automobile carburetor to regulate the airflow entering the engine.

Calculation of Pressure Drop in a Venturi Tube

If an inlet pipe with a diameter of 2.0 cm narrows to a diameter of 1.0 cm, and the initial airflow is 3.0 m/s in the 2-cm section, we can determine the pressure drop in the constricted section. We assume that the air density is 1.25 kg/m³.

Given data:

d₁ = 2 cm = 0.02 m

d₂ = 1 cm = 0.01 m

v = 3 m/s

p = 1.25 kg/m³

Calculation:

Using Bernoulli's principle for the Venturi Tube, we have:

ΔP = ((v²*p)/2)*((A₁²/A₂²)-1)

Calculating the areas:

A₁ = (π*d₁²)/4 = (π*(0.02 m)²)/4 = 0.00031 m²

A₂ = (π*(0.01 m)²)/4 = 0.000079 m²

Substitute the values and calculate:

ΔP = ((3 m/s)²*1.25 kg/m³)/2)*((0.00031 m²)²/(0.000079 m²)²-1) = 80.99 Pa

Therefore, the pressure drop in the constricted section of the Venturi tube is equal to 80.99 Pa.

A Venturi tube is commonly used in which automotive component?

A Venturi tube may be used as the inlet to an automobile carburetor to regulate the airflow entering the engine.