Engineering Thermodynamics Part 1Published on 24/2/2012 and last updated on Thursday 10th of May 2018 at 07:12:31 PM
Science of thermodynamics exists since 19th century and from that time scientists and engineers are making constant and continuous effort of making it as user-friendly as possible. The objective of this section is to throw some light on the art of changing energy available from the sources of fuel like fossil fuel and nuclear fuel in to more usable forms like electrical energy and heat ventilation and air conditioning through the understanding of important concepts of thermodynamics.
Fundamentals of ThermodynamicsThe word thermodynamics is derived from the Greek word theme (means heat) and dynamics (means force). Engineering professionals are interested in studying systems and their interaction with the surroundings. Concepts/Definitions used in this section are helpful for readers in understanding the concept of engineering thermodynamics which is also called Heat-Power Engineering.
System, Surrounding and UniverseSystem is something which we want to study and interested in, thus the first step is to fix precisely the objective of system study. The objective system study can be improving the efficiency of the system or to reduce the losses etc. Example of System can be to analyse the refrigeration cycle in cold storage plant or to analyse the Rankine cycle in power plant. System is defined as a definite mass of pure substance bounded by a closed or flexible surface; similarly the composition of matter inside the system can be fixed or variable depending upon the cycle.
System dimensions need not to be necessarily constant (like air in a compressor is compressed by a piston) it can be variable (like inflated balloon). Matter which interacts with the system externally is called Surrounding and Universe is the outcome of system and surrounding. The element which separates the system from its surrounding is called boundary. Boundary of the system can be fixed or in motion. The interaction between the system and the surrounding takes place by crossing the boundary and thus plays a very important role in thermodynamics (heat and power engineering).
Type of SystemsThere are basic two types of system:
- Closed System or Control Mass: is associated with the definite quantity of matter. Unlike open system in closed system there is no mass flow of matter occurs across the boundary of the system. There is also a special type of closed system which does not interact and isolated itself from the surrounding is called an isolated system.
- Control Volume (Open System): Control volume is limited to a region of space through which mass and energy can flow and cross the boundary of the system. The boundary of a open system is called a controlled surface; this controlled surface can be actual or unreal. Examples of control volume are the equipments that involve flow of mass to cross the boundary of the system like flow of water through pumps, steam flow in turbines and air flow through air compressors.