1. First Law Analysis of Thermodynamic CVs
P M V Subbarao
Professor
Mechanical Engineering Department
Important Engineering Systems for Extra-somatic Needs…..

2. First Law for A Control Volume
Conservation of mass:
Conservation of momentum:
Conservation of energy:

3. More Mathematical Definitions for A CV

4. Thermodynamic Domain of CVs
Steady State Steady Flow Systems
CV, inflows and outflows are invariant.
CV is inhomogeneous.
Rate of work transfer is invariant.
Rate of heat transfer is invariant.
The Total Energy of CV is constant.
Uniform State Uniform Flow Systems
CV is variant but homogenous.
Inflows and outflows are variant and homogeneous.
Rates of work transfer and heat transfer are variant.

5. Manufacturing System as a Thermodynamic CV

6. Auxiliaries (to Manufacturing System) as a Thermodynamic CV

7. Power Plant for A Manufacturing System & Material Processing System

8. Heat Source for A Manufacturing System & Material Processing System
Heat Generation Unit for
Manufacturing System &
Material Processing System

9. First Law for CV:Steady State Steady Flow
Properties of CV are Invariant:
Conservation of mass:
No accumulation or depletion of mass of a CV.
Conservation of energy:
An Uninterrupted service for Extra-somatism!!!
No addition or removal of energy for a CV.

10. Rate of Work and Heat Transfers : SSSF
Both rate of heat transfer and rate of work transfer are invariant.
The work done per unit mass and heat transfer per unit mass are invariant.
The specific work transfer at various parts of a CV can be different.
The specific heat transfer at various parts of a CV can be different.
Let :

11. Comparison of A control mass and SSSF CV during a change of state
Consider compression processes using CM and CV devices.
Reciprocating compressor : A Control Mass : mCM
Initial State : p1,v1 and T1.
Final State : p2,v2 and T2.

12. Centrifugal compressor : A Control Volume @SSSF
Outlet State : pout,vout and Tout.
Inlet State : pin,vin and Tin.
Various parts of A CV are at different states during SSSF process !!