What is the range of coefficient of contraction?

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 coefficient of contraction important?

The coefficient of contraction Cc is an important parameter for accurate discharge measurement in open channels. … The Cc and Cv values under free and submerged flow conditions are obtained from the measured jet velocity and the discharge.

What is relation between CV CC and CD?

= (Actual velocity of jet/ Theoretical velocity) x (Actual area of jet/ Theoretical area) Cd = Cv x Cc. Coefficient of discharge = Coefficient of velocity x Coefficient of contraction.

What is the general value of coefficient of contraction?

Explanation: the ratio of the area of a jet at vena contracta to the area of orifice is known as the coefficient of contraction. the value of cc varies from 0.61 to 0.69 for different orifices.

Can the coefficient of contraction be greater than 1?

Hello . In practice, the discharge coefficient cannot be greater than one. This is a fact. The error may be in compensating the values ​​of the variables in the equation.

What is nozzle meter?

Nozzle meter is bolted between flanges of pipe carrying the fluid. The pressures on upstream and downstream (P1and P2) are noted by using a differential pressure sensor for the calculation of flow rate. Pressure variation along with the pipeline for flow nozzle.

How can you determine the coefficient of contraction?

Coefficient of contraction is defined as the proportion between the areas of the stream at the vena contracta to the area of the orifice. It is denoted by the symbol Cc. Express the coefficient of contraction mathematically. Here, cross-sectional area of the jet is AJ and the cross-sectional area of orifice is Ao.

On what factors does the meter coefficient depend?

In a single phase flow, the discharge coefficient depends mainly on the Reynolds number and the beta factor. Dependence on Reynolds numbers is very weak (except low Reynolds numbers), so the performance of differential flow meters is rather insensitive to liquid viscosity.

What is the relation between coefficient of contraction coefficient of velocity and coefficient of discharge?

Coefficient of discharge (Cd) = Coeff.of flow/velocity (Cv) x Coeff of contraction (Cc). If you know coeff. of flow/velocity (Cv) , you will be able to calculate coeff of discharge (Cd), once Cc is known.

How do you calculate hydraulic coefficient?

It is defined as the ratio of the actual discharge through the orifice (Q) to the theoretical discharge (Qth). The coefficient of discharge is equal to the product of Cc and Cv.

What is coefficient of discharge CD?

It is denoted by “Cd” and is a dimensionless number. In fluid mechanics, coefficient of discharge is the ratio of mass flow rate at the nozzle’s discharge end to that of the ideal nozzle working in ideal flow conditions.

What are hydraulic coefficients name them?

Following are three hydraulic coefficients of orifice: Coefficient of Contraction (Cc) …

What is the theoretical value of the coefficient of contraction for the sharp edge orifice?

for sharp edged orifices the value of Cv is 0.98.

How is the velocity coefficient?

The velocity coefficient can be calculated as the square root of slope divided by roughness. Conventional wisdom dictates that you survey a long-section of the river to obtain slope and then look up roughness from a guide such as Cowan (1956), Chow (1959), or Hicks and Mason (1991).

Why do we calculate coefficient of discharge?

The discharge coefficient can be thought of as a correction factor for “real” flow meter devices. It is typically determined experimentally for different flow meters. Correlation equations can be used to calculate the real “corrected” flow rate through a given meter.

Why the value of coefficient of discharge is less 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 Cd value is high in Venturi meter?

In Venturi meter losses are less so coefficient of discharge is higher whereas in orifice meter due to no convergent and divergent cones there are more losses and hence its coefficient of discharge is less.In venturi meter losses are low due to steamline shape of the diffuser and the pressure gradient is not abrupt as …

What is a high discharge coefficient?

Properties of coefficient of discharge The value of Cd is high in nozzle measurement of flow, whereas its value is small in orifice measurement of flow. • 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 Venturi flow meter?

Venturi meters are flow measurement instruments which use a converging section of pipe to give an increase in the flow velocity and a corresponding pressure drop from which the flowrate can be deduced. They have been in common use for many years, especially in the water supply industry.

How is flow coefficient calculated in CV?

The volume flow rate for liquids can be calculated by multiplying the fluid velocity times the flow area. Thus, Cv is numerically equal to the number of U.S. gallons of water at 60°F that will flow through the valve in one minute when the pressure differential across the valve is one pound per square inch.

What is CD of Venturimeter?

Coefficient of discharge is the ratio of actual discharge to the theoretical discharge. Coefficient of discharge. ⇒ Venturimeter – 0.95 to 0.98. ⇒ Orifice meter – 0.62 to 0.65. ⇒ Nozzle meter – 0.93 to 0.98.

How is orifice flow coefficient calculated?

The discharge coefficient of an orifice or nozzle is defined as the ratio of the actual to theoretical flow rate:

  1. Cd=Measured Flow RateTheoretical Flow Rate (1)
  2. η=σΔp12ρ¯V2 (6)
  3. ξ=σΔp¯Δp (7)

What is orifice coefficient?

The discharge coefficients are used to measure the flow and pressure loss behaviour of nozzles. Orifices and nozzles can be used to reduce pressure or to measure flow rate.

Why is a Venturimeter more accurate than an orifice meter?

Higher flow rates in high quality orifice plates gives increased accuracy. Venturimeters are widely used for high flow rates. They can handle 25-50% more flow rate than an orifice. Orifice plates are smaller in size when compared to venturimeters.

What is the limit value of the coefficient of discharge for Venturimeter?

The effective discharge coefficient for venturi meters ranges from 0.9 to about unity (Streeter, 1951; American Society of Mechanical Engineers, 1983) with turbulent flow, and it varies with diameter ratio of throat to pipe.

Is discharge coefficient and flow coefficient the same?

The Flow Coefficient (Cv in US units, Kv in SI units) is typically associated with the hydraulic performance of a control valve, but other devices such as safety relief valves are characterized by the Discharge Coefficient (Cd, sometimes designated by Kd), which is also associated with orifices and nozzles.

How is the velocity coefficient The discharge coefficient?

Coefficient of Velocity(Cv) is defined as the ratio between the actual velocity of a jet of liquid at vena-contracta and the theoretical velocity of the jet. … Co-efficient of Discharge (Cd) is defined as the ratio of the actual discharge from an orifice to the theoretical discharge from the orifice.

What is CV in fluid mechanics?

Valve Flow Coefficient (Cv) is a valve’s capacity for a liquid or gas to flow through it. It is technically defined as “the volume of water at 60°F (in US gallons) that will flow through a valve per minute with a pressure drop of 1 psi across the valve.”