According to discharge condition, the orifices may be classified as orifices. Differential pressure type flow meters head flow metersmeasure flow rate by introducing a constriction in the flow. The coefficient of discharge is usually given by the text. Ce272 fluid mechanics sessional lab manual ahsanullah. The differential pressure flow measuring principle orificenozzleventuri duration.
The jet that leaves the orifice discharges into the hydraulic bench measuring tank. Flow through venturi meter background and theory introduction flow meters are used in the industry to measure the volumetric flow rate of fluids. On the flow of a compressible fluid through orifices. Calculating flow through orifice and nozzles may be quite frequently required for. Wallaces hints regarding common strengths and weakness of each section of a lab report a sample cover memo. Flow through orifice and mouthpiece discharge hydrology.
Cv, also the volume of liquid escaping from the orifice in time. An orifice is an opening with a closed perimeter through which water flows. Mouthpiece is basically used in order to determine the rate of flow of fluid. A mouthpiece is a short length of a pipe which is 23 times its diameter in length and is fitted in a tank or vessel that contains the fluid. Fm 308 flow measurement by venturi and orifice meter objectives. Flow through mouthpiece a mouthpiece is a short tube of length not more than two to three times its diameter, which is fitted to a tank for measuring discharge of the flow from the tank. This arrangement is known as a borda mouthpiece, after jeancharles borda 17331799. H depth of flow above elevation of cr velocity shall be est in feet approach.
The jet is bound to narrow in this manner because of the curvature of the lines of flow as they pass through the orifice. An annotated sample lab report prepared on a fluids experiment. It consists of a tank provided with inlet supply diffuser, overflow, and provision for fitting orifice or mouthpiece at the outlet of tank. Q dp behind the orifice the pressure recovers partly to its original value. They are simple equations that provide only an estimate of flow rate and aqua environment co. Mouthpieces are basically classified on the basis of. Though intriguing, the situations sometimes can be difficult to assess and evaluate. If v is the velocity of flow at a particular section of the duct and q is the. Pressure in an internal mouthpiece consider a vessel, open to atmosphere at its top, having an orifice with an internal mouthpiece, as shown in fig3. The basic concept a greatly misunderstood and misapplied notion is that of choked flow, also referred to as critical flow. The velocity through which the container evacuates is given as. The installation of flow restnctmg orifices in both the nitrogen gas and instrument air supply lines in the dzero building limits the flow available to the various users. Flow through orifice and mouthpieces and flow through notchs and weirs. The flow area of the fluid at the vena contracta is given as.
Unit iv flow through orifice and mouthpieces and flow through. Orifices are classified on the basis of their cross sectional area. Discharge through a sharpedged orifice may be calculated from. Venturi meter and orifice meter are the commonly used flow meters for measuring massvolumetric flow rate or velocity of the flowing fluid. Explain the principle of orifice meter and derive the equation to find the rate of flow. We know that the jet of the liquid, on entering the mouthpiece, will first contract up to vena contracta c and then expand and fill up the whole orifice as shown in figure. The flow rate and an overflow pipe set the water level.
The article explains the various expressions for solving the parameters involved with fluids or jets of fluids discharging through critical orifices and. These tests were carried out on one type of orifice, transmitting either air or superheated steam, but the theory is more general in character, and further com parisons with tests are needed. The orifice plate is held perpendicular to flow by flanges or a fitting. Such a pipe, which is attached externally to an orifice, is known as an external mouthpiece. Flow through an orifice shows flow through different orifices for different flow rates fluid mechanics key features direct measurement of total head, head loss and diameter of a vertical water jet integral pitot traverse with blade to measure head in the jet and diameter of jet includes a sharpedged orifice. Online calculator to quickly determine water flow rate through an orifice. A pointer gauge arrangement for measuring xy coordinates of jet is also fitted. Present setup is selfcontained water recirculating unit, provided with a sump tank and a. Therefore, flow through the mouthpiece will be quite larger as compared with flow through the orifice. To find the coefficient of discharge for orifice meter. A mouthpiece is short tube fitted to a same size circular opening provided in a tank so that fluid may be discharged. An orifice may be sharp edged or bell mouthed depending on the shape of the entrance edge.
Calibration of an orifice plate flowmeter mechanical engineering department king saud university riyadh submitted by. An orifice is a submerged opening with a closed perimeter through which water flows. Determining the coefficient of discharge for a draining. An orifice is an opening made in the side or bottom of tank, having a closed perimeter, through which the fluid may be discharged. An arrangement is done to vary head and keep it constant at desired level. These variables influence flow rates of gases differently than flow rates of liquids. The orifice meter tube meter run consists of upstream and downstream sections of pipe for which size and tolerance have been determined through calculation and which conform to specifications set forth in ansiapi 2530 gpa 818585 140. For atmospheric inlet pressure and downstream vacuum, both the air velocity and mass flow rate are limited. Hydraulics multiple choice questions and answers set 26.
Their experiment, while not exactly the same as judd and king, showed that the discharge coefficient is a function of the flow s exit velocity through the orifice, especially for reynolds numbers between 1 and 10,000. This application of orifice meters was explored through achieving the following three objectives. Mar, 2018 hydraulic flow through orifices and mouth pieces. Mouthpiece is also used, in some cases, in order to increase the discharge through the orifice. Finally, the discharge through the orifice can be written as. Provided that the necessary orifice plates are machined in a manner similar to that of the prototypes, the orifices for the various lines were sized using the discharge coefficient for the round edge orifice because the calculated values were in good agreement with. Flow of air through orifices under vacuum scfm orifice. This orifice plate creates a measurable pressure difference between its upstream and downstream sides. If the head of the liquid from the centre of the orifice is less than five times the depth of orifice, that orifice will be termed as large orifice. The water supply was admitted to the supply tank and condition was allowed steadying to give a constant head.
Cameron has manufactured measurement orifice plates and restriction orifice plates under north star and nuflo brands, and through the collaboration of its measurement systems and flow control. Manometers measure the total head on the orifice and under the jet. Flow through orifices, mouthpieces, notches and weirs. An orifice is a small opening of crosssection that is present on the side at the bottom of the tank. We know that the jet of the liquid, on entering the mouthpiece, will first contract up to vena contracta c and then expand and fill up the whole orifice. Calculating fluid flow through orifices and mouthpieces. Fluid mechanics lab equipment flow through orifice and. Orifice flow calculation data sheet calculating an orifice diameter it is difficult to accurately calculate the flow of a gas or liquid through a tiny orifice due to the effect of the leading edge of the orifice.
In gas flow through an orifice there is an occasion where the gas velocity. Orifices may have any shape, although they are usually round, square, or rectangular. Fluid mechanics lab equipments orifice and mouthpiece. The flow rate of any gas or liquid can be predicted, regardless of conditions, if the orifice has been flow. Sscafca dpm section 3 hydraulic design 22111 section 3.
Velocity coefficients for free jets from sharpedged orifices the viscositydependence of the velocity coefficient for a free liquid jet, issuing from a sharpedged orifice, is predicted by computing the dissipation of energy in the boundary layer on the back of the orifice plate. It is used for measuring the rate of flow of liquid. For other pressure units, multiply by the conversion factors below. Orifice orifice is a small opening of any crosssection such as circular, triangular, rectangular, etc. The orifice, nozzle and venturi flow rate meters use the bernoulli equation to calculate fluid flow rate using pressure difference through obstructions in the flow sponsored links in a flow metering device based on the bernoulli equation the downstream pressure after an obstruction will be lower than the upstream pressure before.
Jun 24, 2018 difference between orifice and mouthpiece, in the subject of fluid mechanics, in our last post. Fluid mechanics module 4 orifice meter lecture 29 youtube. External mouthpiece mouthpiece pipes fluid mechanics. Difference between orifice and mouthpiece mechanical. Orifice discharge into free air an orifice is an opening with a closed perimeter through which water flows. Pdf flow through an orifice rajkumarsingh mondatta. What is mouthpiece and its classification in hindiab classes. Flow through venturimeter, flow through orifice, flow through mouthpiece, flow over vnotch, flow over sharp crested weir, fluid friction in pipe, head loss due to sudden expansion and sudden contraction of pipe. At best, these figures are only approximate because the flow characteristic of your orifice can only be. Jul 10, 2017 hello, orifice nd mouthpiece both r discharge measuring devices.
Lienhard v velocity coefficients for free jets from sharp. An orifice is a small aperture through which the fluid passes. Fluid flow through small calibrated orifices many variables enter into the calculations of fluid flow through orifices. What is the difference between an orifice and a mouthpiece. Our product range includes a wide range of flow through orifice and mouthpiece apparatus, discharge over notches apparatus, impact of jet on vanes, venturimeter and orifice meter test rig, cavitation apparatus and metacentric height apparatus. To find the coefficient of discharge for venturi meter. Internal mouthpiece mouthpiece pipes fluid mechanics. Orifice and mouthpiece are used to measure the rate of flow of liquid. An orifice plate is a thin plate with a hole in it, which is usually placed in a pipe. An orifice is an opening in the side or base of tank or reservoir through which fluid is discharge in the form of a jet. Orifice, discharge through a submerged or drowned orifice, discharge through a wholly drowned orifice, discharge through a partially drowned orifice, discharge through a drowned orifice under pressure.
Jul 24, 2018 subject fluid mechanics topic module 4 orifice meter lecture 29 faculty venugopal sharma gate academy plus is an effort to initiate free online digital resources for the first time. Flow through a submerged orifice may be computed by applying bernoullis equation to points 1 and 2 in figure below. Hydraulic flow through orifices and mouth pieces youtube. Flow through an orifice detailed specifications h4 tecquipment is committed to a programme of continuous improvement. Exporter of fluid mechanics lab equipments orifice and mouthpiece apparatus, plunger pump demonstration unit, hydraulic bench and axial fan demonstration unit offered by microteknik, ambala, haryana. Aim to study the flow of liquid through orifice and the mouthpiece and determine the coefficient of discharge and coefficient of velocity apparatus single phase power supply. In the case of a sharp edged orifice the inner edge i. The coefficient of contraction c c is the ratio of the smallest area of the jet, the vena contracta, to the area of the orifice. A mouthpiece is short tube fitted to a same size circular opening provided in a tank so that fluid may be discharged through it. All of the jets filled the borda tube under normal conditions. Flow through an orifice typical work assignment head and flow relationships this experiment tests the relationship between head of water above the orifice and flow. Water jet after contraction in mouthpiece touches pipe internal walls. They also produce the coeffi cient of discharge for the ori.
The orifice causes a pressure loss across the plate that increases as flow. This follows because the region where the lines of flow are converging on the orifice is far removed from the walls, and the velocity of the fluid in contact with the walls is negligible. In the case of a sharpedged orifice, the effective diameter is 0. Alright now last part i will discuss the mouthpiece, what is a mouthpiece, mouthpiece.
Fm 308 flow measurement by venturi and orifice meter. Calculating flow through orifice and nozzles may be quite frequently required for engineers dealing with the design of pumps, blowers, fans, turbines etc. Flow through mouthpieces types of mouthpieces, loss of a head of a liquid flowing in a pipe, loss of head due to sudden enlargement, loss of. The discharge will depend up on the head of the fluid h above the level of the orifice. Discharge through an external mouthpiece the discharge through an orifice may be increased by fitting a sufficient length of pipe to the outside of the orifice as shown in figure. Aim to study the flow of liquid through orifice and the mouthpiece and determine the coefficient of discharge and coefficient of velocity.
The relationship between flow rate q and differential pressure dp is a square root function. Application of orifices and its characteristics fluid. Flow through orifice and mouthpiece free download as pdf file. Fluid mechanics lab me 216 f list of experiments 1. Like the venturi meter, the pressure difference varies directly with the flow rate. By fitting the mouthpiece, the discharge through an orifice of the tank can be increased. Ce 321 sample laboratory report packet this packet contains the following materials to help you prepare your lab reports in ce 321. To change the level in the tank and so the head on the orifice, students adjust the flow to the diffuser. Tap water was supplied through an overhead tray at the top of the supply tube. Equations for flow through orifices the following equations give an approximate flow through orifices and short tubes based on orifice size, pressures and gas involved. The narrowing of the jet implies the existence of a transverse pressure gradient. If v is the velocity of flow at a particular section of the duct and q is the discharge, then by continuity equation v q. Apr 25, 2017 flow through mouthpiece a mouthpiece is a short tube of length not more than two to three times its diameter, which is fitted to a tank for measuring discharge of the flow from the tank. Jun 23, 2018 dimension of mouthpiece will be comparatively larger than the dimension of orifice.
They also produce the coefficient of discharge for the orifice over a range of flow. Flow of air through orifices under vacuum scfm orifice diameter inches vacuum level hg. Flow through an orifice typical work assignment head and flow relationships this experiment tests the relationship between head of water above the ori. The thickness of an orifice in the direction of flow is very small in comparison to its other dimensions. There is a remaining pressure loss differential pressure flow measurement with orifice plates and other types of restrictions is standardized by iso 5167. Vacuum flow through orifices this chart approximates the flow that might be expected through a practical orifice. Centre of pressure, proof of bernoullis theorem, flow through venturimeter, flow through orifice, flow through mouthpiece, flow over vnotch, flow over sharp crested weir, fluid friction in pipe, head loss due to sudden expansion and sudden contraction of pipe. Jan 26, 2017 an orifice is an opening made in the side or bottom of tank, having a closed perimeter, through which the fluid may be discharged. Pdf refrigerant flow through flexible shorttube orifices. Classification of orifice and mouthpiece mechanical. Coefficients of discharge for circular orifices paper. Area of xsection of mouthpiece orifice, a, cm 2 area of x section of collecting tank cm 2 area of xsection of supply tank a, cm2 reading on the piezometer at the level on the centre of mouthpiece orifice h 0 a.
Now we will go ahead to find out the classification of orifices and mouthpieces i. In fluid mechanics, both the orifices and mouthpieces are used for measuring the rate of flow of fluid. Refrigerant flow through flexible shorttube orifices. Flows are about 23rds the theoretical flow obtained through a sharp edged orifice. When a fluid whether liquid or gaseous passes through the orifice, its pressure builds up slightly upstream of the orifice. Fundamentals of orifice meter measurement this white paper provides an overview of orifice meter technology, its advantages and general installation recommendations, as well as describes basic gas flow laws and the variables of orifice meter flow equations.
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