Aerospace propulsion - Mathematical and physical tools

The four articles [BM 3 000][BM 3 001][BM 3 002] and [BM 3 003] on aerospace propulsion provide a detailed introduction to the propulsion systems used in aircraft, rockets, and missiles.

This article therefore serves as a reminder of the essential concepts of flight (airfoils, standard atmosphere, etc.), the aerodynamic and thermodynamic formulas used in propulsion at the preliminary design stage, and the different levels of air and combustion modeling.

The main definitions are discussed: constructive index, dilution rate, specific impulse.

What is flight Mach number? How is shutdown temperature or generator pressure defined and used? What are the specific characteristics of supersonic and hypersonic flight? How do we calculate the changes in propellant gas in an engine? What parameters are used to quantify the performance of a propulsion system? Beyond thrust and fuel consumption, how do we quantify other useful aspects? Most engines use energy obtained through combustion. How do we model this?

In this article, particular attention is paid to the link with the design of the flying vehicle whose propulsion we want to study and to the orders of magnitude of the parameters related to a given level of technology.

The examples and data provided, sometimes deliberately left in English, are taken from open literature, as the applications of these engines inevitably lead to restrictions on certain specific aspects of these propulsion systems from a commercial or military point of view.