An unexpected result was an almost immediate resumption of the premod. Discharge coefficient performance of venturi, standard. 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. By measuring the two pressures, engineers can directly calculate the velocity of the fluid. It is that portion of the venturi where the fluid gets converges. By attaching manometers to three sections of the tube, the pressure drop can be measured and the flow rate through the throat calculated. Department of mechanical engineering venturi meter objective. Pressure recovery for venturi tubes is a lot better as compared to the orifice plates. 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. The working of venturimeter is based on the principle of bernoullis equation. 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.
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. 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. Venturimeter is the most widely used device to measure the discharge through the pipe. This also work on the same principle as that of venturimeter. Venturi meter and orifice plate effects are two main and very important phenomenas in fuild mechanics sub field of mechanical engineering. When the flow goes through the contraction it must speed up, and so the pressure must drop. The whole assembly of venturi meter, manometer tubes, scale and manifold is supported on a base mounted on adjustable screwed feet. The venturi meter is an obstruction meter named in honor of giovanni venturi 17461822, an italian physicist who first tested conical expansions and contractions. It uses the same principle as a venturi nozzle, namely bernoullis principle which states that there is a. Definition, parts, working principle, derivation, applications with pdf.
Venturi meter the venturi meter has a converging conical inlet, a cylindrical throat and a. 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. A venturi meter is used to measure the flow rate through a tube. The principle of a venturi meter is depicted in figure 12. The simplest apparatus is a tubular setup known as a venturi tube or simply a venturi plural. If the velocity at any point decreases, the pressure at that point increases due to the conservation of the kinetic energy into pressure energy.
Venturimeters work on bernoullis principle which states that the difference in pressure created across the obstruction gives the measure of the fluid flow rate. Venturi meter problems, bernollis principle, equation of continuity fluid. The theory of the pitot and venturi tubes, part 2 unt. The concentric orifice plate flow meter reduces the pressure by forcing the fluid through a thin plated circular opening. Determination of coefficient of discharge for venturimeter. The drop in pressure can be measured using a differential pressure measuring instrument. A venturi meter is also called a venturi flowmeter. The venturi effect is named after its discoverer, giovanni battista venturi. Definition, parts, working, derivation, applications. Experimental and cfd analysis of flow through venturimeter. Venturi tube exit 2 venturi 3 venturi system venturi entrance 2 water level in pail 4.
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. More commonly, a venturi can use this negative pressure to draw a second fluid into the primary flow. Where cd is the coefficient of venturimeter and its value is less than 1. 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. The venturi flow meter consists of a streamlined contraction and a streamline expansion as shown the diagram. Venturi in 1797 but this principle comes into consideration with the help of c. A venturi meter may also be used to increase the velocity of any type fluid in a pipe at any particular point. To find the coefficient of discharge of a venturi meter to find the coefficient of discharge of an orifice meter theory. Centrifugal pump performance experiment instructors. The venturi meter is invented by an american engineer clemans herchel 18411932 and named him after italian giovanni venturi 18421932. Such a device is called a venturi meter since it relies on the venturi effect. 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.
The following figure shows the venturi meter with uniform cylindrical section before converging entrance, a throat and divergent outlet. Venturimeter engineering explained engineeringclicks. The principle of the orifice meter is identical with that of the venturi 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. Conclusion in this experiment cd the coefficient of. Venturi meter is a device or component which is used for measuring the rate of flow of liquid through pipes. Apr 05, 2018 the theory described on this slide is often seen on web sites and in popular literature. Amrit kumar fluid mechanics hydraulic machines leave a comment. The cross section of the throat is much less than the cross section of the converging and diverging parts. A venturimeter or current meter is used to calculate the change in flow rate through a choked tube as described by the bernoulli equation. 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 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. When comparing the reynolds number to cd for the venturi meter the graph remained relatively linear until there was a drastic. It basically works on the principle of bernoullis theorem. It is a cheaper device as compared to venturimeter. Venturi meterconstruction, working, equation, application. It is used to calculate the velocity of fluids in running through a pipeline. The gradual approach to and the gradual exit from the orifice substantially eliminates boundary layer separation. The original, or classical, venturi was invented by a u. Venturimeter principle, construction and working with diagram. A venturi is a convergingdiverging nozzle of circular crosssection. Fluid flows through a length of pipe of varying diameter. However, it has many more pressure tappings, connecting to water manometers, which allow full study of the pressure distribution along the convergentdivergent passage.
This pressure drop is measured using a differential pressure sensor and when calibrated this pressure drop becomes a measure of flow rate. Venturi meter and orifice meter are the commonly used flow meters for measuring massvolumetric flow rate or velocity of the flowing fluid. This pressure drop is measured using a differential pressure sensor and when. It is mainly used for robust applications as it is known for its durability and is very economical. 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. Daniel measurement and control white papersfundamentals of orifice meter measurement page 1.
To avoid undue aerodynamic drag, a venturi tube typically has an entry cone of 30 degrees and an exit cone of 5 degrees. To determine the coefficient of discharge of the orifice meter 1. 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. Venturimeter principle, construction and working with. 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. Jun 05, 2015 basics of differential flow devices venturi tubes, orifice plates, and flow nozzles duration.
It is the portion that lies in between the converging and diverging part of the venturi. Differential pressure type flow meters head flow metersmeasure flow rate by introducing a constriction in the flow. To find the coefficient of discharge for orifice meter. The standard deviation, for cd was also calculated to be. The theory described on this slide is often seen on web sites and in popular literature. Such a nozzle configuration is called a venturi nozzle and it can be analyzed classically. A simple, inexpensive venturi experiment applying the.
Flow measurement by venturi meter and orifice meter objectives. To find the water flow rate using the venturi meter and the pressure distribution along the meter. Introduction there are many different meters used to measure fluid flow. The theory is based on the idea that the airfoil upper surface is shaped to act as a nozzle which accelerates the flow.
In practise the venturi tube is used in planes to measure the flight velocity. It also offers a particularly clear example of the bernoulli principle. Venturi flow meter evaluate pump performance as a function of impeller shaft speed develop pump. The orifice meter consists of a flat orifice plate with a circular hole drilled in it. Fluid flow is an important part of many processes, including transporting materials from one point to another, mixing of materials, and chemical reactions.
Yamamoto department of chemical engineering, college of engineering and architecture, cebu institute of technology university n. Venturi tubes are appropriate for clean, dirty and viscous liquid and few slurry services as well. 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. It is the portion of the venturimeter venturi where the fluid gets diverges. It has no projections into the fluid, no sharp corners and no sudden changes in contour. In this meter the fluid is accelerated by its passage through a converging cone of angle 15. The differential pressure flow measuring principle orificenozzle venturi duration. Its accuracy for a wide range of instruments is about 0. Venturi flow meter installation and operation manual designs, materials, weights and performance ratings are approximate and subject to change without notice. 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. A venturimeter is a device used for measuring the rate of a flow of a fluid flowing through a pipe. Fm 308 flow measurement by venturi and orifice meter. The venturi meter, also known as venturi tube, belongs to the category of variable head flowmeters.
The flow rate is proportional to the square root of the differential pressure. 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. The fluid whose flow rate is to be measured enters the entry section of the venturi meter with a pressure p1. 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. Flow through venturi meter background and theory introduction flow meters are used in the industry to. 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. Tecquipments bernoullis theorem is typical of meters used throughout industry. Calibration of venturi and orifice meters hirizza junko m. It consists of flat circular plate which has a circular hole, in concentric with 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.
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 venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section or choke of a pipe. 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. 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. Implications of robert venturi s theory of architecture 359 was a tendency in his own work. 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. Hvac applications, or air to furnaces and boilers and for liquids containing particles and slurries. In venturi tubes, pressure loss is low and viscosity effect is high. 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. To find the coefficient of discharge for venturi meter. The venturi flow meter should always be used for turbulent flow.
Converging cone or diameter the area is decreasing throat diameter the area is constant. The principle of venture meter is firstly developed by g. Construction and specification of venturi meter venturi is an example for restriction type flow meter. 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. Implications of robert venturis theory of architecture 359 was a tendency in his own work. Nov 20, 2016 venturi meter and orifice plate effects are two main and very important phenomenas in fuild mechanics sub field of mechanical engineering. Cd for the venturi meter decreased as the flow rate decreased with each trial. 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. The venturimeter is used to measure the discharge along a pipe. Conclusion in this experiment cd, the coefficient of discharge, was calculated for the venturi meter. Fm 308 flow measurement by venturi and orifice meter objectives. The bernoulli balance was applied to the inlet line i. Venturi flow meter installation and operation manual. Flow through venturi meter background and theory introduction flow meters are used in the industry to measure the volumetric flow rate of fluids.
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