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
What is the aim of PDES The aim of PDES is to provide an interface which permits the exchange of data of the entire product development cycle and production cycle, see also PDE

Space Time Structure If the position of the particle  P  changes, the differential change in its position vector r is, in general, given by, d r = d x  i + d y  j + d z  k

After final PWHT, the hardness of the deposited weld metal and heat affected zone (HAZ) shall be examined. Hardness values shall not exceed 200 BHN. Heat treatment shall be perfo

what is the formula for measuring the safe speed to drive for a cyclist

Pumps should be grouped together with good maintenance access to the motor, and good personnel access to seals and suction / discharge valves. Maintenance access should allow for r

Line of action of force: Sol.: The direction of force along the straight line through its point of application, in which force tends to move body to which it is applied. Thi

If Taylor's tool life constants for a provided operation are specified of n = 0.5 and c = 400, what is the percentage increase in tool life when the cutting speed is reduced by hal

Determine about the extent of excavation The extent of excavation depends upon the construction problems like dewatering and uplift. In extreme cases anchoring of the box may b

Thermal Conductivity The amount of heat passing throughout unit cross-section of a solid material in unit time for unit thermal gradient is termed as thermal conductivity. The

what are the types of water turbine and its application ?