Energy and Mass Transfers

Balance Sheet Approach and Basic Concepts, Volume 1

Abdelhanine Benallou

• Publisher: Wiley-ISTE
• Year: 2018
• Print ISBN:
  9781786302748
• eBook ISBN:
  9781119528258
• Edition: 1
• Topic: Physical Sciences
• Subtopic: Thermodynamics

This is the first book of a series aiming at setting the basics for energy engineering. This book presents the fundamentals of heat and mass transfer with a step-by-step approach, based on material and energy balances.

While the topic of heat and mass transfer is an old subject, the way the book introduces the concepts, linking them strongly to the real world and to the present concerns, is particular. The scope of the different developments keeps in mind a practical energy engineering view.

1
Basic Concepts and Balances

1.1. Thermal energy and the first law of thermodynamics

Let us recall that the first law of thermodynamics is a law of energy conservation. It introduces the “internal energy” U, which represents the sum of the energies (kinetic and potential) of the system.

Assuming that there is no mass exchange and that we are considering a closed system that is subject to a thermodynamic transformation between two states, initial (1) and final (2), the variation in internal energy, U(2) – U(1), is the sum of the following two terms:

• – the macroscopic works performed, W_1→2; generally this is the work of the pressure forces;
• – the energy exchange between the system and its outside: Q_1→2.

This is reflected by:

We can therefore deduce a formal definition of the thermal energy (or heat) that is exchanged by the system between the initial state defined by (1) and the final state defined by (2):

For the thermodynamic systems studied, the work involved is generally due to pressure forces. The work is then given by the integral of these forces:

For the systems encountered in heat transfer analyses, volumes are generally constant (isochoric systems). The pressure forces are therefore not at work.

Consequently:...

Table of contents

• Cover
• Table of Contents
• Preface
• Introduction
• 1 Basic Concepts and Balances
• 2 Mechanisms and Laws of Heat Transfer
• 3 Mass Transfer Mechanisms and Processes
• 4 Dimensional Analysis
• Appendix: Database
• Bibliography
• Index
• End User License Agreement