Monday, 15 August 2016

Types of Fluid Flow : Laminar and turbulence flow

Today we will learn about fluid flow. There are many types of fluids which are used in different conditions. The flow of fluid is also as much important as its types because it decide the appropriate application of it.

Types of Fluid Flow :  Laminar and turbulence flow

Types of Fluid Flow:


Fluid flow may be classified according to following ways.

1. Steady and Unsteady flow:

The flow in which characteristics of fluid like velocity, temperature, pressure, density etc. do not changes at a point with time is known as steady flow.

The flow in which characteristics of fluid changes with time at a same point is known as unsteady flow.


Types of Fluid Flow :  Laminar and turbulence flow

2. Uniform and Non Uniform flow

The fluid flow in which the properties of fluid like pressure, temperature, velocity etc. changes with respect time but does not changes with respect position is known as uniform flow.

The fluid flow, in which the properties of fluid like pressure, temperature, velocity etc. changes with respect time as well as with respect position, is known as non-uniform flow.


Types of Fluid Flow :  Laminar and turbulence flow

3. Laminar and turbulence flow

The fluid flow, in which the adjacent layers do not cross each other and move along we define path is known as laminar flow. In this flow, fluid flows along the straight line.

The flow in which adjacent layers cross each other and do not move along well defined path is known as turbulence flow.

Types of Fluid Flow :  Laminar and turbulence flow

4. Rotational and Ir-rotational flow

If the fluid particles flowing along stream lines also rotate about their own axes, then flow is known as rotational flow.

If fluid particles do not rotate about their own axes, then flow is known as irrotational flow.

5. Compressible and In-compressible flow

If the density of fluid varies from point to point in the flow, the flow is known as compressible flow.

If the density of fluid remains constant through the flow, the flow is known as incompressible flow.

We have discussed about types of fluid flow. If you have any doubt regarding this article, ask by commenting.
Read More...

Saturday, 6 August 2016

What is Bearing? What are Main Types of Bearings?

Today we will learn about bearing and types of bearings. Bearing is a machine element that have constrained relative motions and used to reduces friction between moving parts of machine to obtain desired motion or we can say that the machine elements which are support the rotating parts of a machine and reduce friction are called bearings. For example to stop deviation in a shaft of a machine while rotating, a bearing is used.

The word bearing is derived from the verb “to bear”. A bearing is a machine element that allows one part to bear another. The main functions of bearings are

  • To reduce friction between moving rotatory parts.
  • To support rotating parts of a machine.
  • To bear radial and thrust load.


Types of Bearings

Types of bearings:


According to design, load and shape, there are many types of bearings used in industries. The mains bearings can be classified as follows.

According to the Friction:

on the basis of friction bearings are classified as 

1. Friction bearing:

As the name implies, in this bearings the bearing surface is in contact with moving surface or the shaft which produces more friction. These bearing are made up of cast iron, bronze, brass, baibit and white metal having hollow round shape. Lubricant is used for slow moving and heavy weighted running on shaft. These bearings to support crack shaft, rocker arm of IC engine. Friction bearing are also subdivided into following types

Types of Bearings (A.)Solid bearings:
It is a simplest hole made in cast iron to support the shaft and form running fit. These are made up of cast iron or bronze in the form of bush and press-fitted in fabricated or cast iron housings. This is used for small and light shafts moving at low speed. A hole is provided on its face of lubrication.




Types of Bearings (B.)Split bearings:
Split bearings are same like solid bearings but have an arrangement of split. Split bearings are made in halves and assembled in special plumber blocks. It has collar on its external surfaces and also made in two parts as shown in figure.



Types of Bearings (C.)Self-aligning bush bearings:
It consist mainly two parts. The first one is cast iron block and other is bush. These bearing bush are made up of brass or any other soft material in round shape. To protect it from moving, a screw is fixed at one end and this screw is fixed half to the bush and half in block.






Types of Bearings (D.)Adjustable slide bearings:
It can adjust the tightness between bearings and the shaft. This type of bearing has provision for wear adjustment. The bearing is fitted in the tapered hole of the housing for adjustment of wear. The bearing is drawn inside by means of a slotted ring nut.






Advantages and disadvantages of friction bearings:

Advantages:

  • Friction bearings are cheap to produce and have noiseless operation.
  • They can be easily machined, occupy small radial space and have vibration damping properties.
  • They can cope with tapped to the foreign matter.

Disadvantages:

  • It damages machines.
  • It restricts early movement of machine
  • It produces a lot of heat energy.


2. Anti-friction bearing:

The main purpose of these bearings is to minimize the friction in bearing. Due to this reason, the speed of an object increases and friction and temperature decreases. Such bearing have long life. These bearing also sub-divided into following categories.

(A.)Ball bearings:
A ball bearing is a rolling element bearing that used ball to maintain the separation between the bearing races. The width of these bearing is smaller than the bore diameter or ball. On the basis of load and groove cut, ball bearings are classified in the following types.

Types of Bearings (a.)Single row ball bearings:
These bearing have only one groove cut in outer and inner rings with the ball in identical line.








Types of Bearings (b.)Double row ball bearing:
These bearing have two grooves cut in inner and outer rings lie in two rows of the bearing.








Types of Bearings (c.)Self-aligning ball bearings:
These bearings can withstand with journal loads. These loads are generally inclined due to shaft misalignment. These types of bearings have a spherical bore on the outer race.









Types of Bearings (d.)Angular contact ball bearings:
These bearings are designed to take an axial thrust as well as radial loads.











Types of Bearings (e.)Thrust ball bearings:
These bearings are useful for taking vertical thrust load but cannot take any radial load. Some special thrust bearings are available which can also take horizontal end thrust.








(C.)Roller bearings:
Roller bearings are available with the grooved race in the outer and inner members. Roller bearings are capable of carrying the journal (radial) loads. It can work with greater load than ball bearings. To use this bearing, race is required to be locked. On the basis of uses, roller bearings are classified in following types.

Types of Bearings (a.)Self-aligning roller bearings:
These bearings are self-adjustable and it is not affected by non-centering of shaft deformation flexure of shaft and bearing block, so it can compensate the concentricity error caused by these reason.











Types of Bearings (b.)Tapered roller bearings:
These bearings are used to take thrust only one direction. For opposing thrust, the bearings must be mounted in opposite pair. Tapered roller bearings are mainly used for high axial thrust loads.









Types of Bearings (c.)Needle roller bearings:
These types of bearings have very small roller diameter. Rolling element is called needle roller. Needle roller bearings are used where the outside diameter of bearing restricted due to limited bearing space in the housing. The needles fitted in a circular cage which is push-fit in its housing.







Types of Bearings (d.)Cylindrical roller bearings:
These bearings are used in such places, where more load is to be bear. These are made of hollow cylindrical roller.










Types of Bearings (e.)Barrel roller bearings:
The roller fitted in this type of bearing has barrel shape. Its diameter up to full length is uneven. These bearings are self-alignment type bearing, so due to this reason, it has no difficulty to maintain shaft in straight line.








Types of Bearings (f.)Spherical roller bearings:
These bearings are used in such places, where chance of angular condition in shaft may be possible. In these bearings, rollers are fitted in ball cage in such a way that in angular condition, in inner and outer race, the energy transfer can be possible in full capacity.





Advantages and disadvantages of anti-friction bearings:

Advantages:

  • Special shielded bearing does not required lubrication again.
  • It is easy to replace.
  • It has very long life and has very less friction.
  • It easy operates on high speed and required less lubrication.

Disadvantages:

  • Initial cost is usually high.
  • Greater diameter space required for comparable shaft diameter.
  • Dirt, metal chips and so on, entering the bearings can limit their life causing early failure.
  • Lesser capacity to withstand shock


According to the load:

On the basis of load applications bearings are classified as

Types of Bearings 1. Radial or journal bearings:

In this type of bearing, the loading is at right angles to the bearing axis, such that bearing is installed perpendicular to the axial line of the shaft.


Types of Bearings 2. Thrust bearings:

In these types of bearings, the loading is parallel to the bearings axis and collar is used to rotate the shaft at one position.

3. Pivot bearings:

These bearings are used  to the give support to the shaft inn stationary position wherever bearings are in parallel to the axis of the shaft and one edge of the shaft is in the inside of the bearing. These bearings are also known as foot bearing.

4. Slipper bearings:

These bearings provides supports to the moving part or part in the straight line such as cross head which in used in steam engine.


According to the shape:

On the basis of shape bearings are classifed as

Types of Bearings 1. Flat shape bearings:

These types of bearings are flat in shapes which provide support to the sliding parts. Therefore, these bearings are also called slide bearing or guide bearing such as the movement of carriage on lathe bed.




Types of Bearings 2. Round or cylindrical bearings:

These bearings are in round shape which provides support to the moving parts as in case of solid bearing, ball bearing or roller bearing.







Today we have discussed about bearing and different types of bearings in detail. If you have any doubt about this article or if we have missed some other kind of bearings, let me know by commenting. If you have liked this article don't forget to share it. 


Read More...

Friday, 5 August 2016

Types of Fluids

Today we will learn about types of fluid. We know that a substance, which has no fixed shape and able to flow easily in known as fluid. Liquid and gases are considered in this category.  There are various fluids according to their properties and behavior in same atmospheric condition. These are:
Types of Fluids

Types of fluids:

Fluids can be classified as:

Ideal fluid:

A fluid, which is incompressible and having no viscosity, is known as an ideal fluid. Ideal fluid is only an imaginary fluid as all the fluids, which exist, have some viscosity.

Real fluid:

A fluid, which possesses viscosity, is known as real fluid. All the fluids, in actual practice, are real fluids.
Example : Water, Air etc.

Newtonian fluid:

A real fluid, in which shear stress in directly proportional to the rate of shear strain or velocity gradient, is known as a Newtonian fluid.
Example : Water, Benzine etc.

Non Newtonian fluid:

A real fluid, in which shear stress in not directly proportional to the rate of shear strain or velocity gradient, is known as a Non Newtonian fluid.
Example : Plaster, Slurries, Pastes etc. 

Ideal plastic fluid:

A fluid, in which shear stress is more than the yield value and shear stress is proportional to the rate of shear strain or velocity gradient, is known as ideal plastic fluid.

Incompressible fluid:

A fluid, in which the density of fluid does not change which change in external force or pressure, is known as incompressible fluid. All liquid are considered in this category.

Compressible fluid:

A fluid, in which the density of fluid changes while change in external force or pressure, is known as compressible fluid. All gases are considered in this category.

Graphical representation of different fluids:

Types of Fluids

Tabular representation of fluid types:

Types of fluid
Density
Viscosity
Ideal fluid
Constant
Zero
Real fluid
Variable
Non zero
Newtonian fluid
Constant/ Variable
T = u(du/dy)
Non Newtonian fluid
Constant/ Variable
T ≠ u(du/dy)
Incompressible fluid
Constant
Non zero/zero
Compressible fluid
Variable
Non zero/zero

Today we have learned about types of fluids. If you have any query regarding this article, ask by commenting. 
Read More...

Wednesday, 3 August 2016

Fluid Properties : Basic definitions used to define fluids

Today we will discuss about fluids properties. Properties of any material or fluid are used to define its state, condition, behavior and distinguish it from others. There are various types of fluids which behave different in different conditions. For example when we take petrol in a open container, it will evaporate suddenly but the kerosene in same container doesn’t. These all behavior of fluid can be described by its’ properties which knowledge is essential to study about fluid mechanics. 

There are various properties of fluids which are used to define a fluid and its behavior in various fluid applications. These are

Fluid Properties : Basic definitions used to define fluids


Fluid Properties:


Density:

  • Density of a fluid is defined as the mass of the fluid per unit volume.
  • Mathematically it is defined as the ratio of the mass to the volume of the fluid. 

ρ=  Mass/Volume

  • It is depends on the mass and size of the atom of the fluid. Fluids have same volume and different mass have different density. 
  • The SI unit of density is Kg/m3. It is generally denoted by ρ

Fluid Properties : Basic definitions used to define fluids

Specific gravity:

  • It is density of a fluid compared to the density of water which is 1000 Kg/m3. It shows the substance is how much heavy compare to water. 
  • Mathematically it is defined as the ratio of the density of a fluid to the density of water.
S=  (Density of Fluid)/(Density of Water)

  • If the value of specific gravity is greater than one it means the fluid is heavy compared to water and if that fluid mix with water the fluid remain downside of the mixture. If specific gravity is less than one means the fluid is light and can flow over the water in a mixture. 
  • It is a unit less quantity and shown by the S.



Viscosity:

  • The property of fluid due to which, a fluid layer which is flowing with a velocity U, exerts a resistance force on the other layer known as viscosity. 
  • It is a property which offers the resistance force in the flow. A fluid has more viscosity has less flow velocity compare to a fluid has less viscosity. For example oil has more viscosity compared to water.
  • Viscosity of a liquid increases with decreasing in temperature and viscosity of gas increases with increasing in temperature. 
  • According to newton's law of viscosity, the shear stress is directly proportional to the velocity gradient. The constant of the proportionality is known as viscosity. Mathematically 
τ  = µ du/dy

Where µ is known as dynamic viscosity. The unit of dynamic viscosity is Pa-s or N-s/m2.
  • There are two types of viscosity used in fluid mechanics one is known as dynamic viscosity (µ) and other on is known as kinematic viscosity (ν). The kinematic viscosity is ratio of the dynamic viscosity to the density of the fluid. 
ν  = µ/ρ

  • The SI unit of kinematic viscosity is m2/s. 


Specific Weight:

  • It is defined as weight of fluid per unit volume. 
  • Mathematically, it is defined as the ratio of the weight to the volume of the fluid.  

w=  (Weight of the fluid)/(Volume of the fluid)


It can also be expressed as 
w= ρ*g


  • The SI unit of the specific weight is N/m3.


Specific volume:

  • It is the reciprocal of the density or we can say that it is the volume of the fluid per unit mass. 

Specific Volume=  (Volume of the fluid)/(Mass of the fluid)

  • The SI unit of specific volume is m3/Kg.


Vapor Pressure:

  • The pressure exerted by its vapor in phase equilibrium with its liquid at a given temperature is known as vapor pressure.  
  • The vapor pressure of the fluid is increased by increasing in temperature. 
  • It the liquid pressure drops below its vapor pressure at a given temperature, the liquid starts to evaporate. Petrol have more vapor pressure with respect atmospheric pressure at atmospheric temperature, so it starts to evaporate while water doesn't. 

Today we have discussed about fluids properties. If you have any doubt about these properties, ask by commenting. 
Read More...

Saturday, 16 July 2016

Difference between Forging vs Casting

Today I am going to tell you about difference between Forging vs Casting. Casting and forging are both industrial processes of metal forming and shaping. Different process used in different conditions. The main difference between casting and forging is that the metal is compulsory to heat and convert into liquid stage in casting but in forging metal is converted into desire shape by applying pressure with or without applying heat. If the metal is preheated into forging it does not convert into liquid stage. But before differentiate this both terms; you have to know about what is casting and what is forging. So first I am going to tell you about these terms.

Forging vs Casting:


Difference between Forging vs Casting

What is casting?

Casting is a process in which metal is heated until molten stage and pour this liquid metal into a mold or cavity where it is allow solidifying. This process converts the metal into desire shape. It is useful to make complex structure. Most of the industrial structures parts are like lathe machine bed, milling machine bed make big base of other machinery part, IC engine components etc. are made by this process.

Advantages of Casting

  • This process can form very large structure which is impossible to form by other process.
  • It can make any complex and unsymmetrical structure.
  • The structure formed by this process has high compressive strength.
  • It can attain wide range of properties.
  • This process can attain high accuracy.


What is forging?

On the other hand forging is the process of converting metal into desire shape by applying pressure and with or without heat. When the metal is heated before applying pressure the process is called hot forging. In forging metal is heated before below critical temperature or below molten stage. Rolling, pressing, Wire drawing etc. is various types of forging. All sheets, small component, wire etc are formed by this process.


Advantages of Forging:

  • It produces tougher product compare to other.
  • The product made by forging has high impact or tensile strength.


Tabular form of Difference between Forging vs Casting

S. No.
Casting
Forging

1.

The metal is heated until it converts into molten stage.


The metal is heated below recrystallization temperature.

2.

The product produce by it have high compressive strength compare to forging.


It has low compressive strength.

3.

It has low fatigue strength.


It has high fatigue strength.

4.

Imperfection or directional defecates does not improve in casting.


Directional defect are refined in forging.

5.

It is less reliable or has low strength.


It is high reliable.

6.

It is costly sometime and has high lead time.


It has low lead time and cheap compare to casting.

7.

The product has low tensile strength.


This produces high tensile strength.

8.

It required a secondary finishing operation.


It does not require a secondary operation.

Today we have learned about difference between. Casting and forging. If you have any query regarding this article, ask by commenting.
Read More...

Friday, 24 June 2016

Difference between Carnot Cycle and Rankine Cycle

Today I am going to tell you difference between Carnot cycle and Rankine cycle. Both Carnot cycle and Rankine cycle are air standard cycle. Carnot cycle is a ideal cycle of heat engine which gives highest efficiency between given temperature difference but it is a theoretical cycle and actually no engine works on Carnot cycle. Rankine cycle is ideal cycle of vapor or steam power generation. All steam power plant work on this cycle. It used water as the working substance. Both these cycle have different features which I will describe below.

Carnot cycle has two isothermal processes and two isentropic processes. Heat is added and rejected isothermally and compression and expansion take place at constant entropy. It is a theoretical cycle but actually it is difficult to achieve isothermal heat addition and rejection. It gives highest efficiency between given temperature difference. The efficiency of Carnot cycle is given by

As I told Rankine cycle is a ideal vapor power generation cycle used in steam turbine. It consist two isobaric and two isentropic processes. Heat is added and rejected at constant pressure and expansion and compression of gas take place isentropically. In practically first water is pumped to a boiler where heat is added at constant pressure which converts water into steam. This high temperature steam rotates the turbine. This expansion of gas takes places isentropically. Now the heat is rejected into condenser at constant pressure which converts it into water. Now the water is pumped isentropically which complete the cycle. This cycle runs continuously which generate power.

The basic and main difference between Carnot and Rankine cycle is that in Carnot cycle heat is added and rejected at constant pressure and in Rankine cycle heat addition and rejection take place at constant pressure. The other main difference is that the Rankine cycle use water as working substance and Carnot cycle used air as working substance. There are many other differences which are describe below in tabular form.

Difference between Carnot Cycle and Rankine Cycle

Difference between Carnot Cycle and Rankine cycle:


Sr. No.
Carnot Cycle
Rankine Cycle

1.

It is a theoretical cycle. . It gives maximum efficiency between two temperature difference


This one is a practical cycle of steam engine and turbine.

2.

Heat is added and rejected at constant temperature.


Heat is added and rejected at constant pressure.

3.

It has highest efficiency between two temperature differences.


Rankine cycle has lower efficiency than Carnot cycle.

4.

Carnot cycle uses air as the working substance.


Rankine cycle uses water as working substance.

5.

Carnot cycle is ideal cycle for heat engine.


It is ideal cycle for vapor power engine.

Today we have discussed about main difference between Carnot cycle and Rankine Cycle. If you have any query regarding this article, ask by commenting. 

Read More...