Thursday, 22 August 2013

Facts about cylinder volume in cc & litres...

CC: Many engineering students have doubt about the term cc. They know that its about volume in cubic centimetres. But they do not have clear idea about the volume which is described by the term.
Actually, cc is used to describe the volume of engine cylinder. It is different from swept volume because swept volume is the volume of cylinder part which has piston motion. Hence we can also say that the addition of clearance volume and swept volume is the cylinder volume (cc).
Nowadays, cylinder volume is described in "litres" and not in "cc".

It is simple... Take for example a 1.2 litre engine,
    1 litre = 10^(-3) cubic metre,
    1 litre = 10^(-3) × 100^(3) cc... since 1 m = 100 cm,
    1 litre = 10^(3) = 1000cc
Hence, 1.2 l engine means a 1200 cc engine.


Wednesday, 21 August 2013

Why does a car lift up from front while its moving fast?


Might have seen the car nose lifting up in movies. Ever wondered why this happens? It is because of drag. This is because of the eddies formed in the rear side of car, commonly known as Wake.
While the car is moving a backward force is applied to it which is called drag. At the rear many eddies are formed which are responsible for drag force. The force excerted by air has two components.
One is drag force which is in opposite direction of vehicle motion and another is the lift force perpendicular to vehicle motion.
The wake will increase if the separation points are far. That means at rear end the last points having contact of air should be close enough. Hence a streamlined shape is preferable. Hence aerodynamic considerations play a vital role in body design.

Tuesday, 20 August 2013

Common short-forms used in Power Plants

BFP - Boiler Feed Pump, It is the pump which is used to provide feed water to boiler. It is generally hydrocoupled. A booster pump is also used along with the BFP.

CWP- Cooling Water Pump, It is generally a vertical pump used to provide cooling water to the condenser. It extracts the water coming from the cooling towers from the sump and delivers it to the condenser.

ACW - Auxillary Cooling Water, This is sea water which is used in secondary cooling.

RF - Rotary Filters have rotating filters which remove the particles present in the cooling water.


Monday, 19 August 2013

Definition of Ductility and Malleability in terms of Mechanical Engineering.

Simple definition of ductility is the property of a material to form wires and that for malleability it is said that it is the property of a material to form sheets.

But in Mechanical Engineering, we need to be more specific.

A material which can withstand tensile load condition under considerable  deformation without breaking is called Ductile material and that property is called Ductility.

A material which can withstand compressive loads under considerable deformation without breaking is called Malleable material and that property is called Malleability. 

Sunday, 18 August 2013

Difference between the material properties: Hardness, Toughness and Strength.

These three are the major mechanical properties of a material. For a layman these three might be same but for a Mechanical Engineer they are different.

Hardness is the property of a material to resist indentation and scratching. While toughness refers to the resistance to failure. It is the property to withstand strain without tearing. Strength of a material means the maximum load which the material can withstand.


Saturday, 17 August 2013

Facts about Thermal Power Plant...

Most of us know how a thermal power plant works. We know that a thermal power plant works on  Rankine cycle, but do you know what is MOT tank or CPU in power plant?

Condensate Polishing Unit (CPU) has Mixed Bed tanks often called MB tanks which are used for removing very minute particles that may be present in the condensate. The MB tanks have resins which trap the particles and only allow the water to flow.
In supercritical plants this system is kept in operation constantly during the operation of power plant. However, in subcritical plants, they use the CPU every 15 days and do not operate the CPU constantly.

MOT lube oil cooler is used for decreasing the temperature of oil which is used to keep the turbine bearings lubricated. It is a shell and tube type heat exchanger.

Friday, 16 August 2013

Get free e-books from these websites

1. www.bookboon.com
2. www.bookos.org

Check out the MIT open courseware and get free lecture notes + study material. You can get the material for all the courses that are taught in MIT for free.

Did you know?

 High Speed Steel (HSS) has wide range of metal contents. This range of metals contain about 7% carbon, 4% chromium plus additions of tungsten, vanadium, molybdenum and cobalt.  These metals maintain their hardness at temperature up to about 600 degree celcius, but soften rapidly at higher temperatures.  These materials are suitable for cutting mild steel at speed of maximum rates 0.8 m/s to 1.8 m/s.

Time for basics:

This post will clear your doubts about 1st angle & 3rd angle. 1st angle is generally used in India while 3rd angle is used in European countries.

Mechanical Engineering:
First of all, one should have a clear idea about Mechanical Engineering & the role of a Mechanical Engineer. 
Mechanical Engineering is a branch of Engineering which integrates Dynamics, Kinetics, Kinematics, Strength of Materials, Physics, Material Science, Product Design, Manufacturing processes etc to create a product or a system with optimum operating efficiency and cost.
The one doing this job is a Mechanical Engineer.