In industrial applications the knowledge of this effect is used to predict how a fluid will react when flowing through various stages of constricted pipes. A venturi meter may also be used to increase the velocity of any type fluid in a pipe at any particular point. The drop in pressure can be measured using a differential pressure measuring instrument. Venturi in 1797 but this principle comes into consideration with the help of c. The venturi flow meter obtains a pressure differential by constricting the flow area and therefore increasing the velocity at the constriction, which creates a lower pressure according to bernoullis theorem. It is the portion that lies in between the converging and diverging part of the venturi. An orifice meter is basically a type of flow meter used to measure the rate of flow of liquid or gas, especially steam, using the differential pressure measurement principle. Cd for the venturi meter decreased as the flow rate decreased with each trial. Report discussing several aspects of pitot and venturi tubes, including the energy equation for steady adiabatic flow, introduction of mean speed into the energy equation, isentropic flow of an ideal gas, the theory of the pitot tube, and the theory of the venturi meter.
Apr 26, 2015 15 venturi meter vs flow when a venturimeter is placed in a pipe carrying the fluid whose flow rate is to be measured, a pressure drop occurs between the entrance and throat of the venturimeter. The venturi effect is named after its discoverer, giovanni battista venturi. If the velocity at any point decreases, the pressure at that point increases due to the conservation of the kinetic energy into pressure energy. Venturi meter is a device or component which is used for measuring the rate of flow of liquid through pipes. Venturi flow meter working principle animation when a venturi flow meter is placed in a pipe carrying the fluid whose flow rate is to be measured, a pressure drop occurs between the entrance and throat of the venturi meter. The flow rate is proportional to the square root of the differential pressure. More commonly, a venturi can use this negative pressure to draw a second fluid into the primary flow. Implications of robert venturis theory of architecture 359 was a tendency in his own work. Introduction there are many different meters used to measure fluid flow. There are many types of inferential meters available, including. The principle of venturimeter is that when a fluid flows through the venturimeter, it accelerates in the convergent section and decelerates in the divergent section, resulting in a drop in the static pressure followed by a pressure recovery in the flow direction. A simple, inexpensive venturi experiment applying the. In this post the effect of venturi meter and orifice plate on the fluid flow will be disciussed and complete work will be presented in the form of report. Fm 308 flow measurement by venturi and orifice meter objectives.
Venturi tube exit 2 venturi 3 venturi system venturi entrance 2 water level in pail 4. A venturi meter is also called a venturi flowmeter. It is used to calculate the velocity of fluids in running through a pipeline. Daniel measurement and control white papersfundamentals of orifice meter measurement page 1. This pressure drop is measured using a differential pressure sensor and when calibrated this pressure drop becomes a measure of flow rate. Flow measurement by venturi meter and orifice meter objectives. It may be noted that in the usual form of venturi meter intended for flow measurement, pressure tappings are made only at the entrance and at the throat, as these two readings suffice to measure the discharge. Hvac applications, or air to furnaces and boilers and for liquids containing particles and slurries. The principle of venturimeter is that when a fluid flows through the venturimeter, it accelerates in the convergent section and decelerates in the divergent section. The venturi meter has a converging conical inlet, a cylindrical throat and a diverging recovery cone. The principle of venture meter is firstly developed by g. It has no projections into the fluid, no sharp corners and no sudden changes in contour. As the fluid from the entry section of venturi meter flows into the converging section, its pressure keeps on reducing and attains a minimum value p2 when it enters the throat. There is a pressure tap upstream from the orifice plate and another just downstream.
Such a device is called a venturi meter since it relies on the venturi effect. To find the coefficient of discharge of a venturi meter to find the coefficient of discharge of an orifice meter theory. Such a nozzle configuration is called a venturi nozzle and it can be analyzed classically. Jun 05, 2015 basics of differential flow devices venturi tubes, orifice plates, and flow nozzles duration. In practise the venturi tube is used in planes to measure the flight velocity. To avoid undue aerodynamic drag, a venturi tube typically has an entry cone of 30 degrees and an exit cone of 5 degrees. Discharge coefficient performance of venturi, standard. When a fluid, whose flowrate is to be determined, is passed through a venturi meter, there is a drop in the pressure between the inlet section and cylindrical throat of venturi meter. It basically works on the principle of bernoullis theorem.
Fluid flows through a length of pipe of varying diameter. Apr 05, 2018 the theory described on this slide is often seen on web sites and in popular literature. In this meter the fluid is accelerated by its passage through a converging cone of angle 15. Objective the main objectives of this experiment is to obtain the coefficient of discharge from experimental data by utilizing venturi meter and, also the relationship between reynolds number and the coefficient of discharge. The following figure shows the venturi meter with uniform cylindrical section before converging entrance, a throat and divergent outlet. As the fluid enters in the throat, its velocity increases and pressure decreases. Venturi meter is a device in which pressure energy is converted into kinetic energy and it used for measuring the flow rate discharge of the system. Fm 308 flow measurement by venturi and orifice meter. Where cd is the coefficient of venturimeter and its value is less than 1. To find the coefficient of discharge for venturi meter. The meter consists of a pipe with a narrowing throat that expands back to its original diameter on the other side of the choke point. Fluid flow is an important part of many processes, including transporting materials from one point to another, mixing of materials, and chemical reactions. The orifice meter consists of a flat orifice plate with a circular hole drilled in it.
It also offers a particularly clear example of the bernoulli principle. The venturi meter is an obstruction meter named in honor of giovanni venturi 17461822, an italian physicist who first tested conical expansions and contractions. In venturi, pressure energy pe converted into kinetic energy ke to calculate flow rate discharge in a closed pipeline. When the flow goes through the contraction it must speed up, and so the pressure must drop. Venturi meter the venturi meter has a converging conical inlet, a cylindrical throat and a. Flow through venturi meter background and theory introduction flow meters are used in the industry to measure the volumetric flow rate of fluids. It uses the same principle as a venturi nozzle, namely bernoullis principle which states that there is a. Implications of robert venturi s theory of architecture 359 was a tendency in his own work. Venturimeter is the most widely used device to measure the discharge through the pipe. The principle is that when cross sectional area of the flow is reduced then a pressure difference is created between the different areas of flow which helps in measuring the difference in. It is the portion of the venturimeter venturi where the fluid gets diverges. In principle the constriction could be an abrupt change of crosssection, but it is better to use a more gradual constriction and an even more gradual return to the full flow area following the constriction.
Venturi tubes are appropriate for clean, dirty and viscous liquid and few slurry services as well. A venturi meter is a device that allows flow rates through pipes to be calculated by measuring the difference in pressure created by a contraction in a pipe. Nov 20, 2016 venturi meter and orifice plate effects are two main and very important phenomenas in fuild mechanics sub field of mechanical engineering. Venturi flow meter installation and operation manual. Yamamoto department of chemical engineering, college of engineering and architecture, cebu institute of technology university n. The venturimeter is used to measure the discharge along a pipe. Definition, parts, working, derivation, applications. The bernoulli balance was applied to the inlet line i. One of the disadvantages of orifice meters is the large irreversible pressure loss across the orifice, which results in substantial pumping costs in case of large diameter pipes. In this experiment, you will investigate fluid flow in a pipe network and will explore several methods rotameter, orifice and venturi meters for measurement of the fluid flow rate. Venturimeter principle, construction and working with. Flow through venturi meter background and theory introduction flow meters are used in the industry to. The theory is based on the idea that the airfoil upper surface is shaped to act as a nozzle which accelerates the flow.
It consists of flat circular plate which has a circular hole, in concentric with the pipe. Pressure recovery for venturi tubes is a lot better as compared to the orifice plates. The venturi meter, also known as venturi tube, belongs to the category of variable head flowmeters. There are basically two applications for a venturi. This type of a venturi meter is also known as the herschel type and it consists of a smooth gradual contraction from the main pipe size to the throat section, followed by a smooth. The venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section or choke of a pipe. Venturi meter problems, bernollis principle, equation of continuity fluid. Tecquipments bernoullis theorem is typical of meters used throughout industry. The theory of the pitot and venturi tubes, part 2 unt. A venturi is a convergingdiverging nozzle of circular crosssection.
To find the water flow rate using the venturi meter and the pressure distribution along the meter. The whole assembly of venturi meter, manometer tubes, scale and manifold is supported on a base mounted on adjustable screwed feet. This pressure drop is measured using a differential pressure sensor and when calibrated this pressure drop becomes. By attaching manometers to three sections of the tube, the pressure drop can be measured and the flow rate through the throat calculated. The fluid flowing in the pipe is led through a contraction section to a throat, which has a smaller crosssectional area than the pipe, so that the velocity of the fluid through the throat is higher than that in the pipe. The standard deviation, for cd was also calculated to be. By measuring the two pressures, engineers can directly calculate the velocity of the fluid. However, the same principle can be exploited with only minimal pressure loss with the use of a venturi meter. Venturi flow meter evaluate pump performance as a function of impeller shaft speed develop pump. A venturimeter or current meter is used to calculate the change in flow rate through a choked tube as described by the bernoulli equation.
The principle of venturimeter is that when a fluid flows through the venturimeter, it accelerates in the convergent section and decelerates in the divergent section, resulting in a drop in the static pressure followed by a. The theory described on this slide is often seen on web sites and in popular literature. Construction and specification of venturi meter venturi is an example for restriction type flow meter. The theory is the same as for the orifice meter but a much higher proportion of the pressure drop is recoverable than is the case with orifice meters. An unexpected result was an almost immediate resumption of the premod. It is mainly used for robust applications as it is known for its durability and is very economical. Venturimeter engineering explained engineeringclicks. Its accuracy for a wide range of instruments is about 0. Cebu city, 6000 philippines this experiment aims to be calibrate both the venture apparatus and the orifice apparatus. The venturi meter is invented by an american engineer clemans herchel 18411932 and named him after italian giovanni venturi 18421932. Venturi flow meter installation and operation manual designs, materials, weights and performance ratings are approximate and subject to change without notice. The original, or classical, venturi was invented by a u. Venturi meter and orifice meter are the commonly used flow meters for measuring massvolumetric flow rate or velocity of the flowing fluid.
Differential pressure type flow meters head flow metersmeasure flow rate by introducing a constriction in the flow. Department of mechanical engineering venturi meter objective. The fluid whose flow rate is to be measured enters the entry section of the venturi meter with a pressure p1. This pressure drop is measured using a differential pressure sensor and when.
A venturimeter is a device used for measuring the rate of a flow of a fluid flowing through a pipe. Amrit kumar fluid mechanics hydraulic machines leave a comment. When a venture meter is placed in apipe carrying the fluid whose flow rate is to be measured, a pressure drop occurs between the entrance and throat of the. The principle of the orifice meter is identical with that of the venturi meter. Venturimeters work on bernoullis principle which states that the difference in pressure created across the obstruction gives the measure of the fluid flow rate.
The venturi flow meter should always be used for turbulent flow. Venturi meterconstruction, working, equation, application. In simplest form, the pitot tube consists of a glass tube, bent at right. A venturi meter is used to measure the flow rate through a tube.
To determine the coefficient of discharge of the orifice meter 1. The gradual approach to and the gradual exit from the orifice substantially eliminates boundary layer separation. Converging cone or diameter the area is decreasing throat diameter the area is constant. To find the coefficient of discharge for orifice meter. It provides more exact measurement than for example the common pitot tube but it is intended rather for smaller flight velocities the speed of sound is reached in the thinner part at small velocities. Venturimeter principle, construction and working with diagram. This also work on the same principle as that of venturimeter. Oct 02, 20 the venturi tube provides a handy method for mixing fluids or gases, and is popular in carburetors and atomizers, which use the low pressure region generated at the constriction to pull the liquid into the gas flow. Conclusion in this experiment cd the coefficient of. Definition, parts, working principle, derivation, applications with pdf. Venturi meter posted on march 15, 2011 april 4, 2012 by mrsoltys a venturi meter is a device that allows flow rates through pipes to be calculated by measuring the difference in pressure created by a contraction in a pipe. Calibration of venturi and orifice meters hirizza junko m.
Conclusion in this experiment cd, the coefficient of discharge, was calculated for the venturi meter. The venturi flow meter consists of a streamlined contraction and a streamline expansion as shown the diagram. Flow through venturi meter background and theory introduction flow meters are used in the industry to measure the volumetric flow rate of fluids of the modern venturi meter in 1886 by clemons herschel. When a venture meter is placed in apipe carrying the fluid whose flow rate is to be measured, a pressure drop occurs between the entrance and throat of the venturimeter. It is a cheaper device as compared to venturimeter. The cross section of the throat is much less than the cross section of the converging and diverging parts. Centrifugal pump performance experiment instructors. The differential pressure flow measuring principle orificenozzle venturi duration. It is that portion of the venturi where the fluid gets converges. The working of venturimeter is based on the principle of bernoullis equation.
The principle of a venturi meter is depicted in figure 12. Determination of coefficient of discharge for venturimeter. In venturi tubes, pressure loss is low and viscosity effect is high. The simplest apparatus is a tubular setup known as a venturi tube or simply a venturi plural. When comparing the reynolds number to cd for the venturi meter the graph remained relatively linear until there was a drastic. The concentric orifice plate flow meter reduces the pressure by forcing the fluid through a thin plated circular opening.
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