Future Propulsion Systems and Energy Sources in Sustainable Aviation

1Aircraft Engines – A Review

1.1 Introduction

A brief review of aircraft gas turbine propulsion is presented in Chapter 1. Most topics are fundamental to undergraduate propulsion education and thus serve as a refresher before we embark on more advanced propulsion concepts. Aircraft Propulsion, 2nd edition, by the author, provides the bulk of the material presented in this review chapter.

1.2 Aerothermodynamics of Working Fluid

In gas turbine (GT) engines the working fluid is treated as perfect gas, often air, which behaves as continuum rather than individual molecules. The density of the gas, ρ, is a fluid property that is defined on the basis of continuum. The perfect gas law that relates the pressure, density, and the absolute temperature of the gas may be derived rigorously from the kinetic theory of gases. It is stated here without proof:

(1.1)

Where R is known as the gas constant, which is inversely proportional to the molecular mass of the gas, i.e.

(1.2a)

where is the universal gas constant expressed in two systems of units:

(1.2b)

The thermodynamic relations for a ...