Why is the coefficient of discharge less than 1 orifice?

This is the reason why orifice meters are less accurate than venturi meters. Beyond the vena contracta point, the fluid expands again and velocity decreases as pressure increases. Losses in orificemeter are more as there is no convergent and divergent cones and therefore coefficient of discharge is less.

Why the coefficient of discharge of an orifice meter is much smaller than that of a Venturimeter?

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 …

Why the actual discharge through an orifice less than the theoretical discharge?

The thin hole essentially forces the fluid to flow faster through the hole in order to maintain the flow rate. The point of maximum convergence (vena-contracta) usually occurs slightly downstream from the actual physical orifice. This is the reason why orifice meters are less accurate than venturi meters.

What are the factors that affect the discharge coefficient value?

The parameters affecting the discharge coefficient were determined and the relationships between the coefficient and four parameters, that is, the ratio of the water head to the upstream water level, the ratio of orifice height to orifice-weir height, the ratio of orifice height to the water head, and the ratio of the …

Why is the coefficient of discharge greater than 1?

In HEC-RAS the factor attached to the head loss through a culvert or bridge includes both the entrance and exit losses. In fact, the usual assumption is that the outlet loss is equal to the velocity head. This is why you get a factor greater than 1.

Why coefficient of discharge is calculated?

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.

What does the coefficient of discharge represent in measuring the actual discharge of the orifice meter?

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 ideal 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 working …

What is the coefficient of discharge of orifice meter?

A discharge coefficient cd = 0.975 can be indicated as standard, but the value varies noticeably at low values of the Reynolds number. The pressure recovery is much better for the venturi meter than for the orifice plate.

Why coefficient of discharge is important?

This parameter is useful for determining the irrecoverable losses associated with a certain piece of equipment (constriction) in a fluid system, or the “resistance” that piece of equipment imposes upon the flow.

Why is the discharge coefficient important?