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The successful completion of this book “Basic of Mechanical Engineering” would be incomplete without mentioning the names of those people who, provided me constant guidance, support and encouragement during my book writing span. I am overwhelmed as I express my deep sense of gratitude to my most reverted Prof. Gian Bhushan, Professor in Mechanical Engineering Department, NIT, Kurukshetra for his valuable guidance, time, encouragement and kindness that he has showered on me. His knowledge, ideas, wisdom and suggestions increased my awareness which helped me in fruitful completion of this project.

Thermodynamics is defined as the “branch of science which deals with the interaction between the heat and work”[1]. Thermodynamics is also sometimes stated as the science of energy. Thermodynamic deals with the principles of energy and energy conversion in engineering. It also considers the thermodynamic properties of substances. Thermodynamics deals with the conversion of heat into work and vice-versa.

Steam is utilized in steam power plants, steam engines, atomic power plant, and food industry for pasteurization, sterilization, textile industry, paper industry and in railway to generate power. Steam is also utilized in process type industries like sugar industries, textile industries, chemical industries for sizing and bleaching. Steam is also employed to store energy and transported through pipes.

“Steam generator or boiler is, usually, a closed vessel made of steel. Its function is to transfer the heat produced by the combustion of fuel (solid, liquid or gaseous) to water, and ultimately to generate steam” [4] . The American Society of Mechanical Engineers (ASME) [5] gives the following definition of the steam generating unit:

Refrigeration mean cooling i.e. lower the temperature by artificial means. It is a process of attaining lower temperature of the space or product below the surrounding temperature. It further involves maintaining the lower temperature achieved.

A refrigerant is heat transfer medium through which phase change occurs from liquid to vapour i.e. evaporation at low temperature and pressure in the evaporator and then the phase change occurs from gas to liquid i.e. condensation at high pressure and high temperature in the condenser. The cycle of phase change of refrigerant, continues in the refrigeration system.

The application of (VCRS) Vapour compressor refrigeration system is in the air conditioners (window, split, central or precision), car air conditioners, domestic refrigerator etc. The different parts of a domestic refrigerator are: in the hermetical sealed compressor, air cooled condenser, capillary tube, thermo expansion device, filter, rotameter, solenoid valve, temperature control sensor.

Heat engines - A device which change heat received by fuel combustion into mechanical work is called a heat engine. It may be classified into two broad categories viz. are Internal and external combustion engines.[8]

The internal combustion (I.C) engines are functioning on open cycle wherin the air is taken from the atmosphere and the exhaust gases are sent back in the atmosphere. The sequence of operation in a 4-stroke petrol and diesel engine involves Suction compression expansion and exhaust. The precise investigation of I.C engines are very complex due to open cycle system, the working fluid enter and leaves at different condition, quality of fuel and its combustion which make the task more difficult.

Hydraulic turbines is a device which transforms the hydraulic energy or potential energy existing with the working medium to mechanical energy. The working medium is normally water which run the hydraulic turbine. The hydraulic energy is available with water by virtue of its height or altitude. The water which flow through the mountains is stored by constructing a dam or reservoir.

Hydraulic pumps are the devices utilized to transfer pressure energy to liquids at the expense of electrical energy. The electrical energy is transferred to a motor which converts it into mechanical work and a pump is coupled to the shaft. The pump converts the mechanical energy to hydraulic or potential energy. 

Machine: It is a device capable to doing work on application of some effort. Work done by machine is to raise load or to lower load or to do some other types of work like rotation of shaft.

Mechanical power is usually transmitted from one shaft to another by using belts, ropes, chains, gears and clutches. 1. Belts and ropes are utilized if distance between the shafts is large. Belts and ropes are flexible and bend easily. But slip occurs between the belt and the pulley.

Whenever a thin hanging wire is loaded, it elongates and the load moves downwards. Increase in length of wire is governed by the magnitude of the load and nature of wire material. Experimentally it is found that the cohesive force between the molecules of hanging wire offers resistance against the deformation.

Thermal stress arises whenever there is some increase or decrease in temperature of a body which causes either expansion or contraction in the dimension of body. If body is free to expand or contract, with the rise or fall of temperature, there exist no stress in the body. But if deformation of the body is partially or completely resisted then stresses are set up in the body which is known as Thermal Stress. However amount of stress induced in partially prevented deformation will be small than in case deformation is totally prevented.

When any beam is loaded, stresses are induced and so to calculate those stresses, shear force and bending moment acting at load or support location must be required to calculate.

So far we studied direct stress (Tensile or compressive) and tangential stress (shear stress) acting on plane individually. But in many engineering problems these both stresses are acts on a plane at a same time. In such cases resultant stress on that plane will be neither pure normal nor purely shear but there will be combined effect of normal and shear stress.

Over the period of time, the dairy sector has added distinct significance to growing Indian economy. India contributes nearly 19.54% to the global annual milk production with an impressive upliftment of 3.6% in yearly production rate as per the latest available data from FAO International.

1. P. K. Nag, Engineering Thermodynamics. Tata Mc Graw Hill, 2005. 2. Y. A. Cengel and M. A. Boles, Thermodynamics An Engineering Approach. Mc. Graw Hill, 2011.