What is the difference between venturimeter and orifice meter ?

Venturi meter and orifice meter are both types of flow measurement devices used in fluid dynamics. While they serve a similar purpose, there are some key differences between them. Here's a breakdown of their characteristics and distinctions:

Venturi Meter:

Design: A venturi meter consists of a converging section, a throat, and a diverging section. It has a smooth and gradual transition from a larger pipe diameter to a smaller throat diameter and then back to a larger diameter.
Pressure measurement: The pressure difference across the venturi meter is measured using pressure taps located before and within the throat. The pressure difference is related to the flow rate.
Flow profile: The flow profile in a venturi meter is less disturbed compared to an orifice meter. It experiences less energy loss due to its gradual transition, resulting in a lower pressure drop.
Accuracy: Venturi meters generally offer higher accuracy than orifice meters for measuring fluid flow rates.
Applications: Venturi meters are commonly used in applications where accurate flow measurement is required, such as in water treatment plants, industrial processes, and HVAC systems.
Orifice Meter:

Design: An orifice meter consists of a circular orifice plate with a precisely measured hole, installed in a pipe. It creates a pressure drop as the fluid passes through the restriction.
Pressure measurement: The pressure difference across the orifice plate is measured using pressure taps located before and after the plate. The pressure difference is related to the flow rate.
Flow profile: The flow profile in an orifice meter is more disturbed compared to a venturi meter. It experiences greater energy loss due to the sudden contraction and expansion of the fluid, resulting in a higher pressure drop.
Accuracy: Orifice meters have a slightly lower accuracy compared to venturi meters but are still widely used due to their simplicity and cost-effectiveness.
Applications: Orifice meters are commonly used in a wide range of applications, including natural gas and oil pipelines, water distribution networks, and various industrial processes.
In summary, the main differences between a venturi meter and an orifice meter lie in their design, flow profile, and accuracy. Venturi meters offer higher accuracy, have a more gradual transition, and experience lower pressure drop, while orifice meters are simpler, more cost-effective, and have a more disturbed flow profile. The choice between them depends on the specific application requirements, accuracy needs, and budget constraints.