Basic concept of Venturi ejectors

Venturi ejectors are hydraulic devices designed to mix fluids or generate vacuum using the principle of pressure reduction in a constricted conduit. Its operation is based on the Venturi effect, where a moving fluid accelerates as it passes through a reduced section, reducing its pressure and allowing the suction or injection of another fluid or gas.

These devices are widely used in various industrial applications, including chemical dosing, pneumatic conveying, vacuum generation and mixing of gases or liquids in engineering processes. Their simple design and absence of moving parts make them highly reliable and low maintenance.

Fundamentals of the Venturi effect

The Venturi effect is based on the conservation of energy in a moving fluid, expressed by Bernoulli's principle. When a liquid or gas flows through a tapering tube, its velocity increases while the pressure decreases in the narrowed section.

This pressure drop is used in the Venturi ejectors to induce the suction of another fluid or gas towards the main flow, facilitating mixing or vacuum generation without the need for additional mechanical devices.

The relationship between pressure, speed and cross-sectional area allows the operating conditions of the ejector to be precisely calculated, guaranteeing an efficient design adapted to the specific needs of the process.

Flow behavior and energy transfer

Inside the ejector, the driving fluid enters through a converging nozzle where its speed increases considerably. This acceleration generates a static pressure lower than atmospheric pressure in the ejector throat, which is the narrowest point of the duct.

Due to this low pressure, the secondary or suction fluid is drawn through a side port and mixed with the main fluid. The mixture subsequently expands in a divergent section, where the velocity decreases and the pressure partially recovers.