Heat Transfer is one of very important topic under mechanical engineering. Actually, many of engineering students feel this as Most Difficult subject of all. But I will suggest not to panic about it. It can become easy and most of all interesting if approached calmly and steadily.
So, Heat Transfer is mainly divided in three topics, these are called as modes of heat transfer:
- Conduction.
- Convection.
- Radiation.
1. Conduction:
In very simple way, conduction phenomenon can be defined as Heat Transfer through solids. It mainly teaches us about heat transfer through solid walls, cylindrical and spherical objects. We learn to calculate critical insulation radius of system. In core mechanical places like boiler this knowledge is really basic.
Another very wide application of conduction is Heat Transfer through extended surfaces, shortly called as fins. Everybody out have seen these fins on two wheelers’ engine. They provide extended area for heat transfer and increase rate of heat transfer for same base area. This keeps engine of our bike cool or prevents from overheating. Fins have very wide applications. Bike engine is one of them and is very common. Do you know that our fingers also act as fins hence in cold weather our hands and foot becomes a lot colder than abdomen.
2. Convection:
Convection is heat transfer phenomenon which deals with fluids and Heat Transfer through them. Fluids means liquids and gases. This topic becomes large because, we need to learn various fluid properties like, hydrodynamic and thermal boundary layer, laminar flow, turbulent flow etc. Convection is divided into two main divisions, Natural Convection and Forced Convection. Everybody use that ceiling or table fan. Do you know what they do? Its actually most practical use of Forced Convection.
3. Radiation:
Up till now, I have discussed heat transfer phenomenon which needs medium for HT. But radiation is type which doesn’t needs any kind of medium. Solar Energy is of Radiation kind heat transfer. Radiation is most simple type to learn than other two!
So, we have seen three major divisions of heat transfer. Its last part is its widely used applications. i.e. Heat Exchangers. Almost each and every Mechanical Industry needs Heat Exchangers.
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