How is flow orifice size calculated?
Divide the flow of the liquid by the velocity of the liquid to determine the area of the orifice in square feet. In the above example, you would divide 8 by 2. The total area of the orifice would be 4 square feet.
How accurate is a Venturi meter?
Accuracy of +/-1.0 to +/-2.0 percent of actual rate of flow down to approximately 125,000 pipe Reynolds number (Rd). Head loss ranging from eight to 14 percent of differential, depending on the beta ratio of the meter.
What is the advantage and disadvantage of Venturi meter?
Benefits or advantages of Venturimeter ➨It has low head loss which is about 10% of differential pressure head. ➨It can be used to measure higher flow rates in pipes having few meters of diameters. This is due to high coefficient of discharge owing to lower loss.
Which is better orifice or Venturi?
The Venturi meter is insensitive to changes in velocity vector. The velocity vector of fluid must be perpendicular to the orifice plate for lower pressure loss and better accuracy in measurement of average velocity or flow rate or the flowing fluid.
What are the advantages of Venturi meter?
Advantages of venturi meter:
- Less chance of getting stuck with sediment.
- The discharge coefficient is high.
- Its behaviour can be predicted perfectly.
- It can be installed vertically, horizontally, inclined.
- They are more precise and can be used for a wide range of flows.
- About 90% of the pressure drop can be recovered.
What is main disadvantage of orifice meter?
Disadvantages of orifice meter: It causes a pressure drop in the fluid. Its accuracy is affected by the density, pressure and viscosity of the fluid. The range of measurement of viscosity limits of fluids. The pipe must be totally special for the measurement of the flow of liquids.
What are the applications of Venturi meter?
Applications of Venturimeter
- Used in Engine Carburetors (Automobile Sector) to measure airflow.
- Used in process industries (Process and Power Piping Industries) to measure and control process flow.
- In the medical industry, blood flow in the arteries is measured by venturimeters.
Why is Venturimeter preferred over orifice meter?
1. Both are used to calculate the velocity of a fluid. A venturi meter can be used to measure the flow rates of all incompressible fluids (gases with low pressure variations, as wells as liquids), whereas an orifice meter is generally used for measuring the accelerated flow through the apparatus.
Why orifice is needed in our daily life?
An orifice plate is a device used for measuring flow rate, for reducing pressure or for restricting flow (in the latter two cases it is often called a restriction plate ).
How accurate are orifice plate flow meters?
An orifice flowmeter is a very forgiving device and for most applications, with normal care in installation and instrumentation, the measurement accuracy is consistently better than ±1 %. If the measurement error is greater than ±1 %, one must look for obvious errors in installation and instruments.
Why is Venturimeter used?
A venturi meter is also called a venturi flowmeter. It is used to calculate the velocity of fluids in running through a pipeline. The fluid may be a liquid or a gas. The venturi meter calculates velocity by measuring the pressure head at both points before and after the narrowed throat.
What is the principle of Venturimeter?
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.
How do you calculate discharge from a Venturimeter?
EXPERIMENTAL SETUP THE VENTURIMETER IS FITTED IN A PIPE LINE, TO WHICH AN INLET VALVE IS FITTED. THE PRESSURE TAPS ARE PROVIDED AT ENTRANCE SECTION 1 AND THROAT SECTION 2. A U-TUBE MERCURY MANOMETER IS FITTED BETWEEN THESE POINTS 1 AND 2. WATER TANK AND A STOP WATCH IS USED TO MEASURE THE DISCHARGE.
How does a Venturimeter work?
Venturimeter is work on Bernoulli’s equation and its simple principle is when velocity increases pressure decreases. The increases in velocity at the throat result in decreases in pressure at this section , due to this pressure difference is developed between inlet valve and throat of the venturimeter.
What is Venturimeter with proper diagram?
Venturimeter is based on Bernoulli’s theorem. It consists of a two truncated tubes connected by a pipe at narrow ends. The pipe connecting the two tubes is called throat as shown in figure.
What is the difference between Venturimeter and Orificemeter?
A venturi meter can be used to measure the flow rates of all incompressible fluids (gases with low pressure variations, as wells as liquids), whereas an orifice meter is generally used for measuring the flow rate of liquid.
What is meant by discharge in Venturimeter?
In a nozzle or other constriction, the discharge coefficient (also known as coefficient of discharge or efflux coefficient) is the ratio of the actual discharge to the theoretical discharge, i.e., the ratio of the mass flow rate at the discharge end of the nozzle to that of an ideal nozzle which expands an identical …
How do I know my actual discharge?
KV Actual discharge = Actual area at B × Actual velocity at B = Cc × Cu A 2gH( ) we see that the relationship between the coefficients is Cd = Cc × Cu To determine the coefficient of discharge measure the actual discharged volume from the orifice in a given time and compare with the theoretical discharge.
Why actual discharge is less than theoretical discharge?
The reason why Cd values are always less than 1 is because the actual discharge will always be less than the theoretical discharge idealized by Toricelli. This is so due to the effect of surface tension and friction from the external fluid.
Can coefficient of discharge be greater than 1?
Plug in a coefficient for energy losses through turbulence and you have your formula. But you can see indeed that your coefficient can never be greater than one, because that would mean that you end up with more energy than you started with.
Why is Cd less than 1?
Due to friction actual operating head will be less than the actual head measured and therefore, it is less than one.
What is the range of coefficient of discharge?
The orifice discharge coefficients are in the range of 0.6-0.9 and are affected by the fluid viscosity and the size of the vena contracta in the orifice.
Why is the coefficient of discharge less than 1 orifice?
Because of the sudden contraction at the orifice and the subsequent sudden expansion after the orifice, the coefficient of discharge C for the orifice meter is much lower than that of a venturi meter or a flow nozzle.
How do you increase coefficient of discharge?
Properties of coefficient of discharge It can be increased by lowering the convergent angle in flow measurement. It can also be increased when the pressure of working fluid is enhanced.
What is the range of coefficient of velocity?
Very llittle to do with the “Velocity Coefficient”, Cv, just the same name, used by scietists, that is the ratio to a Bernoulli velocity, that can range from 0 to 1 and is adimensional.
How do you calculate orifice discharge coefficient?
The discharge coefficient of an orifice or nozzle is defined as the ratio of the actual to theoretical flow rate:
- Cd=Measured Flow RateTheoretical Flow Rate (1)
- η=σΔp12ρ¯V2 (6)
- ξ=σΔp¯Δp (7)