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. A schematic of the venturi meter is shown on the diagram at the end of the procedure. An orifice meter consists of a flat plate that has a sharpedged hole accurately machined in it and placed concentrically in a pipe as shown in figure 12. To find the coefficient of discharge for venturi meter. When the basic flow input is accessed via the determination of time and either linear dimension, which is volumetric flow, the process is known as primary calibration. The venturi is widely used particularly for large volume liquid and gas flows since it exhibits little pressure loss. Calibration of venturimeter and orificemeter flow measurement. 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. The inlet diameter equals d 26 mm and the throat diameter d 16 mm. Fm 308 flow measurement by venturi and orifice meter. A venturi meter is a device for determining fluid velocities. Venturi flume for measuring water in open channels, in order that those in practical need of such a device may know of its existence.
The water displacement across the manometer is 3 cm. Discharge coefficient performance of venturi, standard. Qk h where is the meter calibration constant and is the manometer reading that measures the pressure drop before and after the orifice. The venturi meter experiment has opened my mind and it has helped me better understand the continuity equation and the bernoulli equation. Furthermore, it is hoped that the construction of larger sizes of venturi flumes than were tested in the laboratory will be encouraged thereby and that they can be calibrated. To plot the coefficient of discharge of a sharp orifice versus reynolds no. The arrangement of orifice meter is much economical than the use of the venturi meter, but as seen in this experiment the venturi meter provide more accurate results that the orifice meter, so the choice of which to use in a specified laboratory depends on the financial ability of the organization occupying the device and on the accuracy needed. Detailed information about these components is given in this chapter. Determination of coefficient of discharge through venturimeter procedure. Pipe with an orifice flow meter, pump with flow control valve, manometer, weighing tank, stop watch. A venturi meter may also be used to increase the velocity of any type fluid in a pipe at any particular point. Venturi meter and orifice meter are the commonly used flow meters for measuring massvolumetric flow rate or velocity of the flowing fluid.
The experiment is designed to study uniform water flow over a range of flow rates. The set of operations that establish, under specified conditions, the relationship between values of quantities indicated by a measuring instrument or measuring system and the corresponding values realized by standards. From consideration of continuity between the mouth of the venturi of area a 1 and the throat of area a 2. Pdf calibration of flow meters lab report samson svondo. Determination of coefficient of discharge venturi meter experiment. The major objective of this experiment was to construct, test and model a simple, inexpensive venturi meter. It consists of flat circular plate which has a circular hole, in concentric with the pipe. The angle of the diverging cone does not influence the calibration coefficient, but it does have an effect on the overall head loss through the tube. A venturimeter is a device used to measure the fluid flow through pipes. Calibration of venturimeter and orificemeter free download as pdf. The whole assembly of venturi meter, manometer tubes, scale and manifold is supported on a base mounted on adjustable screwed feet. Theory the operating principles of these various meters need to be developed in order to meaningfully compare their performance. 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.
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. The lbe flow rates have been measured by the venturinozzle flow meter installed on the feeding conduit, using the equation carried out for the flow meter during the calibration tests, previously. This is an experimental write up for the calibration of flow meters as observed and carried out at the national university of science of technology zimbabwe. This also work on the same principle as that of venturimeter. More specifically, this simple venturi meter, constructed from materials available at a local hardwareauto parts store, was characterized by determining the venturi coefficient and. Flow meter calibrations colorado engineering experiment. The objectives of this experiment were to gain knowledge on pressure and flow measuring devices, and to calibrate an orifice flow meter and a venturi meter. Yamamoto department of chemical engineering, college of engineering and architecture, cebu institute of technology university n. Materials and methods a manometer figure 1, an orifice flow meter figure 2, and a venturi flow meter figure 3 were used to measure the flow rate and pressure change of.
As liquid flows through the pipe, the flow suddenly contracts as it approaches the orifice and then suddenly expands after the orifice back to the full pipe diameter. Within the accuracy of the experiment, the discharge coefficient was independent of the use of a separable conical diffuser in a venturi meter appears feasible and of introduction in situations requiring low pressure loss, the venturi meter is one of the most com monly used devices for the measurement of flow rate. Cebu city, 6000 philippines this experiment aims to be calibrate both the venture apparatus and the orifice apparatus. Bacalso avenue, cebu city chemical engineeing department final report che lab 1 title of experiment juphil a. Calibration of venturi and orifice meters slideshare. The basic principle on which a venturi meter works. The two sections are joined by a constriction that is commonly referred to as the throat. A wet calibration, using actual fluid flow, normally provides the highest calibration accuracy for a flowmeter and sees use where accuracy is a prime concern or when the form of the meter does not lend itself to other methods. Pdf experimental investigation of the installation. Calibration of venturi and orifice meters hirizza junko m. The flow through venturi meter can calculated from the following equation.
The experiment has also increased my knowledge about the turbulent and laminar flow and their causes. Given the measurement error, this application calculates the potential range of flowrates. Venturi meter and orifice plate effects are two main and very important phenomenas in fuild mechanics sub field of mechanical engineering. Venturimeter in a venturi meter there is first a converging section in which the cross sectional area. Bsen 3310 lab 2calibration of orifice flow meter and. Figure 1 venturi meter h5 the venturi meter has three main. However, for smaller pipes orifice meter is a suitable choice. Energy losses through venturi, orifice, and rotameter flowmeters. The third and final type of obstruction meter is the venturi, named in honor of giovanni venturi 17461822, an italian physicist who first tested conical expansions and contractions.
The original, or classical, venturi was invented by a u. One important experiment performed in the laboratory is in the calibration of a meter in a pipeline. Inside the pipe, pressure difference is created by reducing the crosssectional area of the f. Energy losses through venturi, orifice, and rotameter. Amenities for creating standardized flows are necessary for flow meter calibration. The purpose of this experiment is to determine the value of k for a orifice. The water flow rate can be adjusted using the valves on the hydraulics bench. The nozzle flow meter included or any of the optional flow meters quickly and easily fit into place between the adaptors in the base unit of the apparatus. Our calibration capabilities include a wide range of flow rates, temperatures, and pressures utilizing numerous test gasses. Pressure recovery for venturi tubes is a lot better as compared to the orifice plates. To calibrate the given venturimeter and to determine the coefficient of discharge for the same. Venturi meter problems, bernollis principle, equation of continuity.
Fm 308 flow measurement by venturi and orifice meter objectives. Venturi tubes are appropriate for clean, dirty and viscous liquid and few slurry services as well. Cebu city chemical engineeing department final report che lab 1 title of experiment juphil a. This flow measurement device is based on the principle of bernoullis equation. To determine the coefficient of discharge of the venturimeter 2. It is a cheaper device as compared to venturimeter. It basically works on the principle of bernoullis theorem. The most commonly used inferential or rate meter is the thinplate, concentric orifice meter which is the primary device discussed in this paper. To plot the coefficient of discharge of a venture versus reynolds no. With the principle behind its operation being the bernoullis equation, the venturi meter is considered. The concentric orifice plate flow meter reduces the pressure by forcing the fluid through a thin plated circular opening.
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