Internal Flow: Concepts and Applications
Providing students and practicing engineers with a range of analytical tools, this book describes the analysis and behavior of internal flows encountered in propulsion systems, fluid machinery, and ducts.
TABLE OF CONTENTS Internal Flow: Concepts and Applications
10.8: Extensions of the One-Dimensional Concepts II: Compound-Compressible Channel Flow
10.8 Extensions of the One-Dimensional Concepts II: Compound-Compressible Channel Flow
A configuration often encountered in fluid engineering is a duct or other flow system fed by two or more streams of different stagnation pressure or temperature. In turbofan engines, for example, core and fan streams with different stagnation temperatures and pressures can be ducted through a common nozzle with some fraction of the stream supersonic and some fraction subsonic. Computational methods exist for analyzing such flows, but considerable insight can be obtained using an extension of concepts developed for single stream quasi-one-dimensional flow to a multiple stream framework. In this section, following the treatment given by Bernstein et al. (1967), we develop and show applications of this idea for understanding the behavior of non-uniform compressible internal flows.
10.8.1 Introduction to compound flow: two-stream low Mach number (incompressible) flow in a converging nozzle
The principles that underpin compound-compressible nozzle flow analysis are familiar from onedimensional channel flow, but application to even two streams leads to situations that are parametrically complex. It is thus helpful to present first some introduction to compound flow behavior. To do this with minimum complexity, we examine the low Mach number (incompressible flow) limit of an inviscid, two-stream, compound flow in a converging nozzle, noting that the important topic of choking in a compound flow will be dealt with in subsequent sections. The nozzle is considered to be fed by two reservoirs having specified stagnation conditions.
Figure 10.26 shows the nomenclature to be used.
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