Difference Between Laminar and Turbulent Flow

Knowing about the difference between laminar and turbulent flow is very necessary, if you are going to studying the fluid mechanics. They are just the type of fluid flow. When a fluid flows either in the channel or in pipes, it may be either laminar flow or turbulent flow. In this article we will discuss the difference between laminar and turbulent flow.


Difference Between Laminar and Turbulent Flow

Difference Between Laminar and Turbulent Flow

S.no
Laminar Flow
Turbulent Flow
1.
It is a fluid flow in which the fluid layers move parallel to each other and do not cross each other.
It is a fluid flow in which the fluid layers cross each other and do not move parallel to each other.
2.
The laminar flow generally occurs in the fluid flowing with low velocity.
The turbulent flow occurs when the fluid flows with high velocity.
3.
Laminar flow occurs in the small diameter pipes in which fluid flows with low velocity.
Turbulent flow occurs in large diameter pipes in which fluid flows with high velocity.
4.
The fluid flow is laminar when the value of Reynolds number (Re) is less than 2000.
The fluid flow is turbulent when the value of Reynolds number is greater than 4000.
5.
Shear stress in laminar flow depends only on the viscosity of the fluid and independent of the density.
Shear stress in the turbulent flow depends upon the density of the fluid.
6.
The fluid flow is very orderly i.e. there is no mixing of adjacent layers of the fluid and they move parallel to each other and also with the walls of the pipe.
The fluid flow is not orderly i.e. there is mixing of adjacent layers of fluid with each other and they do not move parallel to each other and also with the walls of the pipe.

Summary of the Difference Between Laminar and Turbulent Flow

Laminar Flow

  • The fluid flow in which the adjacent layers of the fluid do not mix with each other and moves parallel to each other, is called laminar flow.
  • In the laminar flow, the fluid layer moves in straight line.
  • The laminar flow always occurs when the fluid flow with low velocity and in small diameter pipes.
  • The fluid flow having Reynolds number less than 2000 is called laminar flow.
  • The fluid flow is very orderly i.e. there is no mixing of adjacent layers of the fluid and they move parallel to each other and also with the walls of the pipe.
  • Shear stress in laminar flow depends only on the viscosity of the fluid and independent of the density.

Turbulent Flow

  • The fluid flow in which the adjacent layers of the fluid cross each other and do not move parallel to each other, is called turbulent flow.
  • In turbulent flow the fluid layers do not moves in straight line. They move randomly in zigzag manner.
  • The turbulent flow occurs when the velocity of the fluid is high and it flows through larger diameter pipes.
  • The fluid flow having Reynolds number greater than 4000 is called turbulent flow.
  • The fluid does not flow in definite order. There is a mixing of different layers and they do not move parallel to each other but crosses each other.
  • The shear stress in turbulent flow depends upon its density.

For better explanation watch the video given below:



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Scotch Marine Boiler Construction, Working, Advantages with Diagram

In this article we will learn about scotch marine boiler construction, working, advantages and application. It is the most common boiler which is used on ships in marine works. It is a type of fire tube boiler. After reading this article you will able to learn its construction, types, working and advantages.

Scotch Marine Boiler

Scotch marine boiler is a fire tube boiler. It is also a scotch or tank type boiler which is used for the marine works. The reason behind, it is used for marine work is its compactness, efficiency in operation and its ability to work in any type of water. Brick work setting and external flues are not required in scotch marine boiler.

Scotch Marine Boiler

Types 

It is of two types:

1. Single Ended
2. Double Ended 

Single Ended Scotch Marine Boiler:

  • The length of the single ended steam boiler may be upto 3.5 m
  • The single ended steam boiler contains one to four furnaces and these furnaces enter from the front end of the boiler.

Double Ended Scotch Marine Boiler:

  • The length of double ended steam boiler is upto 6.5 m.
  • In double ended scotch marine boiler, the furnaces are present on both of its ends. And the number of furnaces varies from 2 to 4 in each end.

Construction

The various parts of scotch marine boiler are as follows

1. Furnace: It is used to burn the fuel inside the boiler. A single ended scotch marine boiler is fired with four furnaces. The furnaces are generally corrugated for strength. Each furnace has its own combustion chamber.

2. Combustion chamber: It is portion of the boiler where the combustion of the fuel takes place. There are fine plates in the combustion chamber , which require staying i.e. the top plate, back plate, two side plate and the tube plate. There are number of smoke tubes placed horizontally and connect the combustion chamber to the chimney.

3. Smoke box: The smoke box has numbers of smoke tubes which is placed horizontally and connects the combustion chamber to the chimney. The smoke passes through these smokes tubes and finally enters into the chimney.

4. Chimney: It is used to exhaust the smoke and burnt gases out of the boiler. The exhaust gases is released into the environment through chimney.

5. Boiler shell: The boiler shell is made up of steel plate. It protects the internal parts of the boiler. All the important fittings of the boiler are fitted on the boiler shell.


Working 

The working of Scotch Marine boiler are as follows:

Scotch Marine Boiler


The fuel is inserted into the furnace through the fire hole. The fuel in the furnace is ignited through the fire hole. The burnt fuel enters into the combustion chamber. Here the combustion of the fuel takes place. The heat generated into the combustion chamber is used to heat the water surrounding the combustion chamber. The water gets converted into steam and it is supplies to steam turbine. The exhaust gases after combustion passes through the smoke tubes and reaches to the chimney. The chimney releases these smoke and exhaust gases into the atmosphere. In the scotch marine boiler the water surrounds the furnace, combustion chamber and smoke tubes and due to this it provides the greater heating surface to the water. 

For better understanding lets discuss its working step by step.

  • First the fuel is inserted into the furnace through the fire hole and here it is ignited.
  • The fuel is burnt on the furnace and hot burnt gases are generated. This hot burnt gas enters into the combustion chamber. A large amount of heat is generated into the combustion chamber. The heat form the combustion chamber use to heat the water surrounds it. 
  • The water gets converted into steam and made to pass on the steam turbine.
  • The water surrounds the furnace, combustion chamber and smoke tubes and due to this the scotch marine boiler provides a greater heating surface for the water.
  • The burnt exhaust gas passes to the chimney through smoke tubes. 
  • The chimney releases these exhaust gases or smoke in the atmosphere.
  • In this boiler the level of water is maintained a little above the combustion chamber.


Application

This boiler is generally used in marine works and on ships. This is because of its compactness, efficiency in operation and its ability to work in any type of water.

Advantages

The various advantages of scotch marine boiler are as follows:

  • It is compact in size.
  • It has good efficiency in operation.
  • It has the ability to work in any type of water.
  • Brick work setting and external flues are not required in scotch marine boiler
This is all about the Scotch Marine Boiler. If you find anything Missing or incorrect than don't forget to comment us. And if you like this article than like us on Facebook.


Manual Vs Automatic Transmission

In this article we will learn about Manual Vs  Automatic transmission. Now a days the cars that comes in the market equipped with either manual transmission or automatic transmission. The basic difference between manual and automatic transmission is that in manual transmission the shifting of gears is done by the driver and in automatic transmission the shifting of gears takes place automatically. The cars that has automatic transmission can also be operated manually. Let's discuss about them in detail.

Manual Vs  Automatic Transmission

Manual Vs  Automatic Transmission


Manual transmission (MT): The Transmission in which the shifting of gears is done by the driver is called the manual transmission.
  • The cost of the cars with manual transmission is less.
  • Its maintenance cost is less.
  • It does not require active cooling.
  • The fuel efficiency of the manual transmission is more. It also depends the driving skills of the driver.
  • Its design is simple and less complex.
  • Different sets of gears are present in manual transmission to get different gear ratios.  
  • Manual transmission is not easy to derive. High skilled driver is needed to drive manual transmission cars.
  • The driver requires more attention while driving a car with manual transmission.
  • Clutch pedal is used to shift the gears in MT.  
  • It does not allow multitasking during driving.
  • It gives you more ways to control your car because the driver has the choice to shift the gears according to his requirement and experience.
  • In manual transmission cars there is three pedals to operate the car. These three pedals are of clutch, brakes and acceleration.
  • It has low resale value.
  • The MT cars are difficult to operate in high density traffic area due to manual changing of gears.

Automatic Transmission (AT): The transmission in which the shifting of gears done by the car is called automatic transmission.
  • The cost of automatic transmission cars is much higher than the MT cars.
  • It requires active cooling due to overheating problem.
  • The fuel efficiency is less as compared with the manual transmission.
  • The design is more complex due to number of components.
  • Same set of gears produces all of the different gear ratios.
  • Cars with automatic transmission are much easier to drive.
  • Less skilled driver can also drive AT cars.
  • Not much attention is required to operate automatic transmission cars.
  • No clutch pedal is there, automatic shifting of gears takes place according to the speed of the car.
  • It allows multitasking during driving.
  • It does not provide you more ways to control your car.
  • In the automatic transmission cars there is two pedal s to operate the car. These two pedals are of brake and accelerator.
  • It has high resale value.
  • It is easier to drive on steep hills.
  • The AT cars are very easier to operate in the high density traffic area due to automatic changing of gears by the car itself. 

Manual Vs  Automatic Transmission or Difference Between Manual and Automatic Transmission in Tabular Form:

S. No
Manual Transmission
Automatic Transmission
1.
In the manual transmission the shifting of the gears is done by the driver.
In the automatic transmission the shifting of gears is done by the car itself.
2.
The cost of the manual transmission cars is less.
The cost of automatic transmission cars is much higher than the MT cars.
3.
The maintenance  cost is less
The maintenance cost is high
4.
It does not require active cooling.
It requires active cooling due to overheating problem.
5.
The fuel efficiency of manual transmission is more. It depends upon the driving skills of the driver.
The fuel efficiency is less as compared with the manual transmission.
6.
The design is simple and less complex.
The design is more complex due to number of components.
7.
Different sets of gears are present to get different gear ratios.
Same set of gears produces all of the different gear ratios.
8.
Manual transmission cars are not easy to drive.
Cars with automatic transmission are much easier to drive.
9.
High skilled driver is required to drive MT cars.
Less skilled driver can also drive AT cars.
10.
Requires more attention of the driver to operate manual transmission cars.
Not much attention is required to operate automatic transmission cars.
11.
Clutch pedal is used to shift the gears.
No clutch pedal is there, automatic shifting of gears takes place according to the speed of the car.
12.
It does not allow multitasking during driving.
It allows multitasking during driving.
13.
It gives you more ways to control your car.
It does not provide you more ways to control your car.
14.
In manual transmission cars there is three pedals to operate the car. These three pedals are of clutch, brakes and acceleration.
In the automatic transmission cars there is two pedals to operate the car. These two pedals are of brake and accelerator.
15.
It has low resale value.
It has high resale value.
16.
It is not easier to drive on steep hills.
It is easier to drive on steep hills.
17.
The MT cars are difficult to operate in high density traffic area due to manual changing of gears.
The AT cars are very easier to operate in the high density traffic area due to automatic changing of gears by the car itself.

For Better Understanding Watch the Video:



This is all about the manual vs automatic Transmission. If you find anything 
missing or incorrect than comments us. If you find this article informative than like and share.



Steam Power Plant Construction,Working, Advantages and Disadvantages with Diagram

The steam power plant is the important source to produce the electricity. The major portion of electricity demand is fulfilled by the steam power plant. It is also called as thermal power plant. It provides the electricity requirement to different areas. In this article we will study about the construction,working, efficiency, advantages and disadvantages of steam power plant.

Steam Power Plant

It is the power plant which is used to generate electricity by the use steam turbine. The major components of this power plant are boiler, steam turbine, condenser and water feed pump. 


Steam Power Plant

Site Selection 

The site selection of steam power plant depends upon various factors. Let's discuss about these factors one by one

  1. Cost of the land: The cost of the land which is selected for the installation should be minimum or economical.
  2. Population density of the land: The distance of the steam power plant from the public area should be at appropriate distance. So that in case of any failure or hazard happen in the plant, the population of the area near to the power plant should not be affected.
  3. Availability of water sources: There should be a plenty of water sources in the selected area. Since the power plant requires a large amount of water for the generation of steam.
  4. Availability of fuel: The availability of required fuel (coal) should be there because without fuel the plant will not work.
  5. Type of land: The land which is selected for the power plant installation should be plain enough and it is suitable for the strong foundation for the various machinery of the plant.
  6. Scope for the future demand: The size of the land should be such that it is capable for the handling of future power demand.
  7. Availability of Ash handling facility: Proper ash handling facility should be available near the power plant to minimise the adverse effect of the ash produced in the steam power plant
  8. Availability of transportation facility: The transportation facility is must in the installation for the power plant, because any material cannot be transported to the power plant form its required location in lack of transport. There should be easy availability of proper transportation facility at the selected site.

Construction or Layout of Steam Power Plant

There are so many components present in the steam power plant which performs their specialized function for the efficient working. The various component of the steam power plant are:

Steam Power Plant layout

  1. Coal Storage: It is the place where coal is stored which can be utilised when required.
  2. Coal Handling: Here the coal is converted into the pulverised form before feeding to the furnace. A proper system is designed to transport the pulverised coal to the boiler furnace.
  3. Boiler: It converts the water into high pressure steam. It contains the furnace inside or outside the boiler shell. The combustion of coal takes place in the furnace.
  4. Air-preheater: It is used to pre-heat the air before entering into the boiler furnace. The pre heating of air helps in the burning of fuel to a greater extent. It takes the heat from the burnt gases from the furnace to heat the air from the atmosphere.
  5. Economiser: As its name indicates it economises the working of the boiler. It heats the feed water to a specified temperature before it enters into the boiler drum. It takes the heat from the burnt gases from the furnace to do so.
  6. Turbine: It is the mechanical device which converts the kinetic energy of the steam to the mechanical energy. 
  7. Generator: It is coupled with the turbine rotor and converts the mechanical energy of the turbine to the electrical energy.
  8. Ash Storage: It is used to store the ash after burning of the coal.
  9. Dust Collector: It collects the dust particle from the burnt gases before it is released to the chimney.
  10. Condenser: It condensate the steam that leaves out turbine. It converts the low pressure steam to water. It is attached to the cooling tower.
  11. Cooling Tower: It is a tower which contains cold water. Cold water is circulates to the condenser for the cooling of the residual steam from the turbine.
  12. Chimney: It is used to release the hot burnt gases or smoke from the furnace to the environment at appropriate height. The height of the tower is very high such that it can easily throw the smoke and exhaust gases at the appropriate height. And it cannot affect the population living near the steam power plant.
  13. Feed Water ump: It is used to transport the feed water to the boiler.

Working 

Steam Power Plant Working

In the steam power plant the pulverised coal is fed into the boiler and it is burnt in the furnace. The water present in the boiler drum changes to high pressure steam. From the boiler the high pressure steam passed to the super heater where it is again heated upto its dryness. This super heated steam strikes the turbine blades with a high speed and the turbine starts rotating at high speed. A generator is attached to the rotor of the turbine and as the turbine rotates it also rotates with the speed of the turbine. The generator converts the mechanical energy of the turbine into electrical energy. After striking on the turbine the steam leaves the turbine and enters into the condenser. The steam gets condensed with the help of cold water from the cooling tower. The condensed water with the feed water enters into the economiser. In the economiser the feed water gets heated up before entering into the boiler. This heating of water increases the efficiency of the boiler. The exhaust gases from the furnace pass through the super heater, economiser and air pre-heater. The heat of this exhaust gases is utilised in the heating of steam in the super heater, feed water in the economiser and air in the air pre-heater. After burning of the coal into the furnace, it is transported to ash handling plant and finally to the ash storage.

For better understanding, the step by step working of steam power plant is as follows
  • The pulverised coal is fed into the boiler where the pulverised coal is burnt into the furnace
  • Due to heat from the furnace, the water present in the boiler drum changes to the high pressure steam.
  • From the boiler this high pressure steam is passed to the super heater where it is again heated up to its dryness.
  • After that this super heated steam strikes the turbine blades with a high speed and the turbine blades starts rotating to at high speed. Here the stored potential energy of the steam is gets converted into mechanical energy.
  • A generator is coupled with the turbine rotor. As the turbine rotates, the generator also rotate with same speed and mechanical energy of the turbine gets converted into electrical energy.
  • Steam after hitting the turbines blades lost its most of the energy and leaves the turbine with low pressure steam.
  • This low pressure steam enters into the condenser. Cold water circulates in the condenser from the cooling tower. Here the low pressure wet steam is converted into water.
  • After that condensed water with the feed water passed to the economiser where it gets heated up by the economiser. And finally the feed water enters into the boiler by a feed water pump to repeat the cycle.
  • The burnt flue gases from the furnace passes through the super heater, economiser and air pre-heater. This heat of the flue gases is used to heat the steam in the super heater to its dryness, to heat feed water in the economiser before entering into the boiler and to heat air form the atmosphere in the air pre-heater before it enters into the furnace.
  • The ash from the furnace is transported to ash handling plant and finally to the ash storage.
Watch the Video for Better Comprehension


Efficiency of steam power plant

  • The power plant that operates on coal constitutes almost 41% of the world’s electricity generation.
  • It is the modified Rankine thermodynamic cycle on which the coal fired power plant operates.
  • The overall efficiency of the coal power plant ranges from 32% to 42%. And this is calculated by the superheat pressures, and super heat and reheat temperatures of steam.
  • Most of the large power plants that operates at steam pressures of 170 bar,570 ℃ superheat and  570 ℃ reheat steam temperatures can achieve the efficiency ranges from 35% to 38%.
  • The efficiency of the super critical power plants operating at 220 bar steam pressure, 600/600 ℃ superheat/reheat temperatures can achieve is 42%.
  • The efficiency in the range of 45 to 48% can be achieved by the ultra-super critical power plants operating at 300 bar pressure, 600/600 ℃ superheat/reheat steam temperatures.

Advantages and disadvantages 

The advantages and disadvantages of steam power plant are as follows:

Advantages

  • As compared with power generating plant, it has low initial cost and hence economical.
  • Less land area is required as compared with the hydro power plant.
  • Coal is used as fuel and the cost of coal is cheaper than petrol and diesel fuel. So the power generation cost is economical.
  • This power plant has easy maintenance cost.
  • Steam power plant can be installed in any area where water sources and transportation facility are easily available.

Disadvantages

  • The running cost of steam power plant is comparatively high because of fuel, maintenance etc
  • If we talk about the overall efficiency of steam power plant, than is about 35 % to 41% which is low.
  • Due to the release of burnt gases of the coal or fuel, it contributes to the global warming to a larger extent.
  • The heated water that is thrown in the rivers, ponds etc puts and adverse effect on the living organism of water and disturbs the ecology.
In this article we have studied about the construction, working, advantages and disadvantages and efficiency of steam power plant. If you find anything missing or incorrect than don't forget to comment us. And if you like this article than like us on Facebook.


Forging vs casting

In this article we will study about forging vs casting. In the manufacturing process these two processes forging and casting is very crucial. Without them it is impossible to make any machinery, tools, shape etc. Forging and casting both are used in the manufacturing industries but they have a lot of difference between them. Here we will discuss about forging vs casting in detail.

Forging vs casting

What is Forging?

Forging vs casting


It is a processes in which the metals and alloys are changed to the specific shape by compressive forces exerted by some external agencies. These external agencies may be hammers, rolls, press and an upsetting machine.

  • The portion of work in which forging is done is called forge.

Why forging is used?

  • Forging is used when a less complex object is needed to manufacture and of less heavy weight.
  • It is used to get greater strength, high tensile strength, high degree of surface finish, greater productivity, more reliability, greater dimensional accuracy, greater fatigue strength etc in desired product. 

Where forging is used?

Forging is used in making rail road equipment, small tools, automobile tools and parts, in aviation industries etc.

How forging is done?


For more understanding about Forging, watch the video.



What is casting?

Forging vs casting


It is a process in which the material is heated to its molten state and this liquid molten material is poured into a mold of desired cavity and left to solidify. After solidification the pattern that we get is called casting. The casting is taken out of the mold when the process completed.

  • The metals are the general materials used for the casting

Why casting is used?

  • Casting is a very old process for forming any material in desired shape. It is a 6000 year old process.
  • Casting is used to make complex shapes which are not easy to manufacture commercially by other manufacturing process.

Where casting is used?

  • Casting is used to make complex parts of any machine.
  • It is used in automobile industries, aerospace, railways and shipping for manufacturing different parts.
  • It is used to manufacture electrical equipment like motors, generators, pumps and compressor.
  • If we talk about hardware industry than there, it is used to produce plumbing pipes, joints, fittings, valves etc.
  • It is used to manufacture household equipment like gardening and kitchen equipment, furniture and fittings.
  • There are other areas where casting is used or we can say that almost every industry use the processes of casting to manufacture their respective products.

 How casting is done?

For more understanding about casting, watch the video.


Difference between forging and casting


  • In forging the material is heated below its recystallisation temperature but in casting the material is heated upto its molten state.
  • The objects formed by forging have less compressive strength as compared with the casting.
  • The fatigue strength of the product in the forging is high. In the casting the fatigue strength is less.
  • In forging the imperfection or directional defect improves but it is not so in case of casting.
  • The object produced in the forging has more reliability as compared with the object produced in the casting.
  • The forging process provides greater tensile strength to the body than casting.
  • In forging there is no requirement of secondary finishing operation but in casting secondary finish operation is must to get the desired dimensions. Sometimes forging also requires secondary finish operation.
  • High dimension accuracy is obtained in the forging as compared with the casting.
  • Less wastage of material as no secondary finishing operation is required. In casting wastage of material is more as secondary finishing operation is required.
  • Forging gives greater productivity than casting.
  • Grain orientation is favorable in forging but it is not possible in case of casting.
  • High degree of surface finish is obtained in forging. The surface finish in case of casting is not of high degree of accuracy as compared with the forging.
  • The cost of material and lead time is less in forging. In casting the cost and lead time is more.

Forging vs Casting or Difference Between Forging and Casting in Tabular Form

S.no
Parameter
Forging
Casting
1.
Heating of material
Material is heated below its recrystallisation temperature.
Material is heated upto its molten state.
2.
Compressive strength
Less
High
3.
Fatigue strength
High
less
4.
Improvement of imperfection or directional defects
Yes
No
5.
Reliability
High
Less
6.
Tensile strength
High
less
7.
Requirement of secondary finishing operation
No
Yes
8.
Dimensional accuracy
High
Less
9.
Material wastage
Less
More
10.
Productivity
High
Less
11.
Favorability of grain orientation
Yes
No
12.
Degree of surface finish
High
Less
13.
Cost of manufacturing
less
more


In this article we have studied about forging vs casting. If you find anything missing or incorrect than comment us. And if you find this article informative than don't forget to like us on Facebook.