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
can anybody tells me about t-s n p-h diagram? just about the concept and working principle.can anybody help me? thank you. :)

A semi circular frame of flexural rigidity EI is built at A and caries a vertical load W at B. calculate the magnitude of the vertical and horizontal deflection at B and hence the

(a) Evaluate the natural frequency of system shown in figure and show that it will be equal to (b) calculate equivalent stiffness of two springs connected in parallel.


State the types of foundations We saw the different types of foundations commonly adopted for specific situation. In actual practice the situations are not very simple both in

Tensile and Compressive Force: T ensil e Forces A force, that pulls the body, is called as tensile force. Here member AB is tension member carrying tensile force P. As

Find out the Acceleration of the mass centre: A wheel of mass 200 kg and a diameter of 700 mm rolls without slipping down a plane inclined at an angle of 20 o with the horizo

Rankine cycle - Thermodynamics: The major problems of Carnot cycle is compressing very wet steam mixture from the condenser pressure up to boiler pressure. The trouble can be

brifely explain 2r-2p invertion

Dry Friction: Dry friction (also called as coulomb friction manifests when the contact surfaces are dry and there is tendency for the relative motion. Dry friction is fu