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
Compare the hardenability of Ferrous Alloys vs Non-Ferrous Alloys

Difference between path function and point function

A steel rod of 20 mm diameter passes centrally through a copper tube of 50 mm external diameter and 40 mm internal diameter. The tube is closed at each end by rigid plates of negli

How to solve wedge problems..can anyone just explain the method..

Inlet and Exhaust Valves : Valves are commonly mushroom shaped poppet type. They are provided on the cylinder for regulation of the charge coming into the cylinder (inlet valve)

Define density and specific volume. DENSITY (ρ) Density is illustrated as mass per unit volume; Density = mass/ volume; ρ = m/v, kg/m 3 P for Hg = 13.6 × 10 3 kg/m 3

With the help of diagram , depict the evaluation of Machine Design. Discuss in detail Technical feasibility, finanacial and economic feasibility, social and environmental feasib

How the boiler are classified? Sketch and define the babcock & Wilcox boiler and also Compare the water tube boiler and fire tube?

Relation between stress and strain: The relation between stress and strain is generally shown by plotting a stress-strain (σ -e) diagram. Stress can be plotted on ordinate (ve

Working Chamber of EBW The chamber is usually rectangular in shape and has heavy windows to permit viewing the work. Both high voltage machines and low voltage machines