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
diffrence between actual and idealactual vapour compression cycle

In a nuclear power plant saturated steam at 30 bar enters a h.p. turbine and expands isentrophically to a pressure at which its quality is 0.841. At this pressure the steam is pass

(a) Prove that the fourier series expansion for the function x(t) described in the finite interval -π ≤ t≤ π x(t) = 0 -π ≤ t ≤ 0 x(t) = sint 0 ≤ t ≤ π (b) Represent t

Registering a Small Scale Unit: Small Scale and ancillary units (i.e. undertaking with investment in plant and machinery of less than Rs. 6.0 million and Rs. 7.5 million respectiv

Discover the fixing torques set up at the ends of the shaft: A solid shaft 6.5 m long is securely fixed at each of the end. A torque of 91 Nm is applied to the shaft at a sect

Illustrate the process of knock in C.I engines and compare it with S.I. engine knock. What is Octane rating of C.I. engine fuel. What is the difference between chemical delay and p

Plastic material and rigid plastic material: For the plastic material, there is stress at which plastic deformation begins. A rigid plastic material is one in which the ela

advanced cam profile synthesis

Lasers with Solid State Lasing Mediums For an active medium, the solid state laser uses lasing ions which are suspended in a rod shaped solid matrix. These "dopants" in the rod

Plate clutch lifter bolts for even tightening : Reset clutch assembly using plate lifter clutch alignment tool.