Thursday, 8 March 2018



Automotive mechanical by Joseph heithes (For subject point of view and object queation) I. C.Engine by v. Gnesan ( For problem point of view) I.C.Engine by Mathur and sharma Thermodynamics :-It is the field of science which deals with energy possessed by gases and vapors,  It's conversion in terms of heat and work and it's relationship between various properties of system. System:-Reference to any space,  A matter or a group of Metter within a definite Boundary whether real or imaginary is defined as a system. Surrounding:-Any matter that is outside the boundary and affect the behavior of system is defined as surrounding. Shown the gas inside the piston cylinder arrangement is a system both Boundary B1 and B2. Cylinder is system for the boundary B2 and surrounding for the boundary B1 P, V, T = Are the fundamental properties of gas. Properties:-Property of a system is that quantity which belongs to the system.  And without which the system cannot exist. Thus P, V, Railway are known as the fundamental properties of system. Heat and work are not a property of system. Note- Heat is not a property of gas because without heat gas is existing. If volume is constant then work is zero so work is not property of gas. 

TYPES of system. Close system, Flow system or open system, isolated system Open system when there is no mass transfer but only energy transfer taking place across the boundary.  Then system is known as a closed system. Gas inside a piston-cylinder arrangement is a good example for closed system. Open flow system when there is both mass and energy transfer taking place a cross the boundary the system is then referred as a open or flow system. Ex. For a flow system is the flow of fluid through a duct or pipe. Isolated system An isolated system is a system that is completely isolated or separated from the surrounding. In this case, there is neither mass nor energy transfer taking place across the boundary. Ex. For the isolated system is the gas inside thermals flask the energy associated with a closed system is known as transit energy. The energy associated with flow system is called flow energy flow energy is a energy that is integrated with a mass Another type of energy that remains constant within the boundary even if mass transfer take place such on energy is known as stored energy . Internal energy is good example for stored energy. 

Work done for an open system. Let us consider a gas flowing through a duct from section A1A2 to section B1B2. If is imagine that the flow of the gas takes place due to piston formed by the different layer of the fluid. Before section A1A2 is 'p'  then the work done on the section of the fluid at A1A2 will be, Work done = Force X Displacement = F X L= ( pressure X Area )  X length W= (p X A) X L Where, A= cross section area of duct L= Distant between two layer A1 and B2 Thus,  W= P x volume P= const. The above equation will appear as an energy term for all the flow system. The pressure is given by the height and the volume is given by the length of diagram. Any condition and state of gas is represented  by particular point in the diagram this point is thus known as the state point of the gas The P-V diagram is also known as indicator diagram. Process: - when a system undergoes a change from one condition to another condition. (One state point to another state point) It is then said to have complete a process. Note: - without addition of mass there is change of volume is called expansion

          Cycle When a system after undergoing a no.  Of process is able to retain its original condition (original pressure volume and temperature), the system is than said to have completed a cycle.Of a cycle is not completed, then continuous work will not be obtained? The order in which the different operation should take place for completing a cycle is an follow Heat added, Work done (expansion)  output, Heat rejection, Compression Ideal cycle :- It is the cycle in which the expansion and compression process will take place adiabatically and reversible ( Isentropic process ) When a system undergoes a process in such a manner that it is able to retain its original condition by following the same path in the reverse direction then the proces is said to be reversible process. On the other hand if the abatement is unable to retain its original condition then process is than said to be irreversible  Also if the system is able to retain its original condition along a different path the process is still irreversible The difference between reversible and irreversible process ( ideal and actual conditions )  is without friction and with friction . 

Thermal equilibrium when there is no heat transfer between two bodies then they are said to be in thermal equilibrium with each other. Under ideal condition the temperature of two bodies will be the same when they are in thermal equilibrium with one another. Zeroth law when two bodies are in thermal equilibrium with a third body then first two bodies will also be thermal equilibrium with one another. Quasi-static process ( it is only theoretical ) When a system undergoes a process in such a manner that the final condition is nearest to the original or thermal equilibrium condition ,  the process is then known as quasi static process. A quasi-static process is the same as different calculus in math. A quasi-static process is used under condition. When any quantity will remain constant but it's keeps on changing 

A quasi-static process can be used for reversible process only. (It cannot be used for irreversible process)  Work done for closed system ( by using quasi-static process) Let us consider a closed system undergoing change from state point 1 to 2.  In such a manner that process and volume changes from p1V1 to P2V2,  a b shown in Figure is a quasi-static process.  The change in pressure for the quasi-static process is negligible. If they assumed constant pressure for quasi - static process is p and change in volume is dv then Work done for this quasi-static process is given by, TYPES of process Constant volume process( isd Horicon or isometric ), Constant volume process ( Isobaric process), Constant temperature process ( isothermal process or hyperbolic process - valid for gases only)  The adiabatic process no heat transfer Polytrophic process ( P, V and T is changes and heat transfer not =0 ) Important question Determine the Work done for a different process undergone by a closed system or non flow system .  Undergoing change as shown in the above diagram. Solution 

C. V process When ,  v = constant then dv =0 Pdu =Pxo = p x 0 = 0 note :- remaining notes i will completed in few days. The DOF of cam and follower is always 1 For any followers DOF is the number of inputs required to get constrained output in any chain . Spring as a link:- A link of flexible length.

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