SARDAR PATEL COLLEGE OF

ENGINEERING , BAKROL

Name:-PRAJAPATI TIRATH A.• BRANCH:-CIVIL (B)

• ENROLLMENT NO:-151240106066

• SUBJECT:-FLUID MECHANICS(2130602)

• TOPIC:-ORIFICE TYPES

• Guided by:- VIKRAM PANCHAL

ORIFICE

Orifice is a small opening of any cross-section (such as circular, triangular, rectangular, etc.) on the side or at the bottom of a tank, through which a fluid is flowing.

The orifice is used to measure discharge. An orifice is provided in verticle side of the tank or in the base.

Classification of orifices:

1). According to shape of orifice2). According to size of orifice3). According to Shape of edge4). According to Nature of discharge

The sub-merged orifices are further classified as

a). Fully sub-merged orificesb). Partially sub-merged orifices

1). The orifices are classified as small orifice or large orifice depending upon the size of orifice and head of liquid from the centre of the orifice.

If the head of the liquid from the centre of orifice is more than five times the depth of the orifice, the orifice is called small orifice.

And if the head of the liquid is less than five times the depth of orifice , it is known as large orifice.

2). On the basis of their cross-sectional areas they are classified as

Circular orificeTriangular orificeRectangular orificeSquare orifice

SUBMERGED ORIFICE• A submerged orifice and the same orifice discharging freely have nearly the same

coefficient of discharge.

• Submerging an orifice provides the capability to measure relatively large flows with a small drop in water surface, conserving delivery head compared with weirs.

• However, the submerged orifice requires head measurements upstream and downstream.

3). Depending upon the nature of discharge, orifices are classified as

Free discharging orificesFully drowned orificesPartially drowned orifice

4).Depending upon the shape of upstream edge of the orifices, they are classified as

Sharp-edged orifices Bell-mouthed orifices

WorkingOrifice meter is device used to determine the rate of flow through pipe.

It consist of flat circular plate which has a sharp edged circular hole called orifice.

It is fixed concentric to pipe.

The orifice diameter is generally kept half of the diameter of the pipe.

It is based on the same principle as explained in venturimeter.

The value of Cd varies between 0.60 to 0.65.

It is a economical and less space is required for fitting.

Advantages of orifice meter• Orifices are small plates and easy to install/remove.• Offer very little pressure drop of which 60% to 65% is recovered.• Orifice meter can be easily maintained.• Measures a wide range of flow rates.• They have a simple construction.• They have easily fitted between flanges.• They are most suitable for most gases and liquids.• They are inexpensive.• Price does not increase dramatically with size.

Disadvantages of orifice meter

• Requires homogeneous fluid.• Requires single phase liquid.• Requires axial velocity vector flow.• Causes a pressure drop in fluid.• Their accuracy is affected by density , pressure and viscosity fluid.• Fluid viscosity limits measuring range.• Requires straight pipe runs to ensure accuracy is maintained.• Pipe line must be fully especially for liquid flow measurement.• They have low range-ability.

MOUTHPIECES

A mouthpiece is a short length of a pipe which is two or three times its diameter in length, fitted in a tank or vessel containing the fluid.It is used for measuring the rate of flow of liquid.

Classification of mouthpieces:

1). Depending upon their position with respect to the tank they are classified as External mouthpieces Internal mouthpieces

2). Depending upon their shape they are classified as

Cylindrical mouthpieces Convergent mouthpieces Convergent-divergent mouthpieces

3). Depending upon the nature of discharge at the outlet of mouthpiece they are classified as

Mouthpieces running full Mouthpieces running free

A mouthpiece is said to be running free if the jet of the liquid after contraction does not touch the sides of mouthpiece .

But if the jet after contraction expands and fills the whole mouthpiece it is known as running full.

THANKYOU