Introduction Flow Meter

INTRODUCTION The flow meter demonstration apparatus experiment illustrates the typical methods of flow measurement of incompressible liquids. This apparatus are able to demonstrate the flow measurement comparison of different types of condition which are the venture meter, orifice device and the rotameter.

The accessory is designed to be positioned on the side channels of the hydraulics bench top channel. The Venturi meter, variable area meter and the orifice plate are installed in a series configuration to permit direct comparison. Flow through the test section is regulated using a flow control valve. This together with the bench control valve permits variation of the system static  pressure. Pressure tappings in the circuit are connected to an eight-bank manometer which incorporates an air inlet/outlet valve in the top manifold with facilities to connect a hand pump. This enables the levels in the manometer bank to be adjusted to a convenient level to suit the system static pressure. The pressure tappings for the manometers are arranged to give a set of readings around the flow meters in the system. The setup is detailed elsewhere.

Fluid mechanics has developed an analytical discipline from the application of the classical laws of static, dynamics and thermodynamics, to situation in which fluids can be treated as continuous continuou s media. The particular laws involved are those of o f conservation of mass; these laws may be simplified in an attempt to describe quantitatively the behavior of th e fluids. The hydraulic bench service module, mod ule, F1-10, provides the necessary nec essary facilities to support a comprehensive range of hydraulic models each of which is designed to demonstrate a particular p articular aspect of hydraulic theory. The specific hydraulic model that is concerned for this experiment is the flow meter test rig (F121). This consists of venture meter, variable area meter, and orifice plate installed in a series of configurations to allow for direct comparisons.

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Orifice

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 Nozzles

Venturi

Venturi meter Venturi meter is a tube with constricted throat that increase velocit y and decrease  pressure. Venturi meter is used to measure the flowrate of compressible and incompressible fluid in a pipeline. When a fluid flows through a throat section, which has a smaller cross sectional area than in a pipe, the velocity of the fluid through a throat is higher than in the pipe. If velocity higher, pressure will drop. By measuring pressure drop, discharge may be calculated. Beyond the throat the fluid is decelerated in a pipe of slowly diverging section (sometimes referred to as a diffuser) in order to recover as much of the kinetic energy as possible. We must know the principle of Bernoullies equation to understand the principles of venturi meter.

Orifice plate The orifice meter is also used in measuring the flow rate of a reservoir or through a pipe. The orifice meter consists of a flat plate with a circular hole drilled in it. There is pressure tap upstream from the orifice plate and another just downstream.

Variable area meter. The variable area flowmeter is a simple, reliable, inexpensive, and easy-to-install flowmeter with low pressure drop and no electrical connection that givesa direct reading of flow rate for a wide range of liquids and gases.

-easurement #pparatus $-/0/% apparatus is designed to operate together with a basic hydraulic bench or any water to familiari&e the students with typical methodsof flow measurement of an incompressible fluid.The app aratus is able to demonstrate the flow measurement comparison by using aventuri meter, orifice meter and -ethod, the flowcomparison can be further used to compare against the flow measurement of the hydraulics bench, depending on the type of hydraulics bench in use. (ther features of the flow ap  paratusinclude a 90 degree elbow with pressure tapping before and after this elbow. The purpose of these features is to provide an added function to this apparatus to allow students to calculate thetotal head loss and loss coefficient when fluid flows through these devices.2enturi meter  Fig 1.1: Venturi meter

The venturi meter consists of a venturi to measure the flow rate of compressible and incompressible fluid in a pipeline. Theventuri tube has a converging portion, a throat and a diverging portion. The function of theconverging portion is to increase the velocity of the fluid and lower its static pressure. # pressure

difference between inlet and throat is thus developed, which pressure difference is correlatedwith the rate of discharge. The diverging cone serves to change the area of the stream bac" to theentrance area and convert velocity head into pressure head.(rifice meter  Fig 1.2: Orifice meter

consists of a flat plate with a circular hole drilled in it. There is pressure tap upstream from theorifice plate and another at downstream.3otameter

OBJECTIVES 

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To study and compared the operation and the characteristic of three different types of flow meter which is the venture meter, the rotameter and the orifice. To obtain the flow rate measurement by utilizing three basic types of flow measuring technique To investigate the loss coefficient of fluid through 90 degree elbow.