First law- closed system undergoing change of state, Mechanical Engineering

First Law for Closed System Undergoing Change of State - thermodynamics:

In accordance to first law, when system undergoes a thermodynamic process (change of state) heat and work transfer of both take place. The net energy transfer is stored within the system and is called as stored energy or total energy of system.

When process is executed by system the change in stored energy of system is numerically equal to the net heat interaction minus net work interaction at the time of process.

  dE = dQ - dW                                                                                                   ...(i)

  E2  - E1  = Q1-2  - W1-2

Here E is an extensive property and represents total energy of system at a given state, that is,

E = Total energy

dE = dPE + dKE + dU

If there is no change in Potential Energy and Kinetic Energy
 then, PE = KE = 0 dE = dU, putting in equation (1), we get dU = dQ - dW

or                          dQ = dU + dW

This is the 1st law of thermodynamics for the closed system. Here,

  dU = Change in Internal Energy dW = Work Transfer = PdV

  dQ = Heat Transfer = mcdT

{Heat added to system is taken as positive (+ve) and heat removal by the system is taken as negative} For a cycle              

 dU = 0; dQ = dW

 

Posted Date: 10/15/2012 2:13:15 AM | Location : United States







Related Discussions:- First law- closed system undergoing change of state, Assignment Help, Ask Question on First law- closed system undergoing change of state, Get Answer, Expert's Help, First law- closed system undergoing change of state Discussions

Write discussion on First law- closed system undergoing change of state
Your posts are moderated
Related Questions
Study literature and give a discussion of the applicability of the continuum mechanics hypothesis to the nano-scale mechanics (solids and fluids). Your paper must be detailed but c

Explain concept of Drill Power feed of the spindle is a common feature. Also coolant system is a ordinary feature of the radial drilling machine. Radial drilling machines ca

state a note on reversible and irreversible process?

Soldering Soldering is defined as a metal joining process wherein coalescence is produced by heating the surfaces to be joined to a suitable temperature and melting the fille

Q. Define spot welding electrodes • To conduct the welding current to the work pieces. • To transmit to the work pieces in the weld area the amount of force needed to pro

Manifolds The surface of a solid must satisfy some conditions so that the resulting solid is well-behaved. This is the so-called manifold condition. While recent research has s

the pump, shown in the figure, is used to deliver water to a distribution system. there is no flow to or from reservoir A, but it is used to damp pressure and protect the pump. th

Borides Borides of Mo, W, Cr, Ti and Zr find extensive industrial application. They exhibit extremely high hardness, melting point from 1800 to 3000 o C and good chemical resi

Calculate the radius of plates: A laminated steel spring, simply supported at the ends & centrally loaded, along a span of 0.8 m; is needed to carry a proof load of 8 kN; and

5. Calculate and draw the Shear force and Bending moment diagrams for the loaded beam and determine the maximum moment M and its location x from left end