First Law Analysis of Thermodynamic CVs P M

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

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

More Mathematical Definitions for A CV

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.

Manufacturing System as a Thermodynamic CV

Auxiliaries (to Manufacturing System) as a Thermodynamic CV

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

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

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.

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 :

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 : m. CM Initial State : p 1, v 1 and T 1. Final State : p 2, v 2 and T 2.

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 !!