How a Venturi Nozzle Works

Core Principle

The Venturi nozzle operates on the principle that flow velocity increases and static pressure decreases as a fluid passes through a converging channel. This phenomenon follows Bernoulli's principle and the continuity equation: at a given flow rate, the smaller the cross-sectional area, the higher the velocity and the lower the static pressure.

Operating Process

Step 1: Contraction and Acceleration

Pressurized motive water (or another liquid) enters the Venturi nozzle and first passes through the contraction section. As the channel cross-sectional area gradually decreases, the fluid velocity increases sharply, reaching its maximum at the throat.

Step 2: Throat Vacuum and Suction

At the throat, the high-speed jet causes a significant drop in static pressure in this region. When the throat pressure falls below that of the medium connected to the suction port (air, oxygen, ozone, or other liquids), a negative pressure (vacuum) is formed, and the external medium is continuously drawn into the throat.

Step 3: Shearing and Mixing

The entrained medium meets the high-speed motive water at the throat and is subjected to intense shearing, tearing, and dispersion. The gas phase is broken into fine bubbles, and the liquid is thoroughly dispersed — the two complete highly efficient mixing and mass transfer within an extremely short time.

Step 4: Diffusion and Delivery

The mixed fluid then enters the gradually expanding diffuser section, where the flow area progressively increases and the velocity gradually decreases. A portion of the kinetic energy is converted into pressure energy, providing the mixed fluid with sufficient discharge pressure at the outlet for delivery to a tank, vessel, or downstream pipeline.

Key Requirements

The Venturi nozzle itself has no moving parts and requires no separate mechanical suction device. However, to reliably produce suction and mixing effects, the following conditions must be met simultaneously:

• Sufficient flow and pressure provided by an external power source such as a water pump
• A necessary pressure differential between inlet and outlet (typically no less than 25%–30%)
• Nozzle throat dimensions matched to the system operating conditions

As long as the above conditions are satisfied, the Venturi nozzle can continuously and stably draw in gas or liquid, enabling a variety of process functions including gas–liquid mixing, liquid–liquid mixing, aeration and oxygenation, ozone dosing, and hydraulic mixing.

Contact Information

Company Website: https://www.cd-greenwater.com
Technical Contact Number: 028-85130135
Customer Service Contact Number: 18515915124
Contact Email: jane1984@cd-greenwater.com
Address: No. 191, Section 1, Changcheng Road, Xihanggang, Shuangliu District, Chengdu