# Accession Number:

## ADP000335

# Title:

## Mixing of Compressible Flows with Application to Ejector Thrusters,

# Descriptive Note:

# Corporate Author:

## FLIGHT DYNAMICS RESEARCH CORP VAN NUYS CALIF

# Personal Author(s):

# Report Date:

## 1982-06-01

# Pagination or Media Count:

## 22.0

# Abstract:

Mixing of two streams of compressible fluid having arbitrary properties at the start of mixing results in one of two possible states upon conclusion of the mixing process. These two final states can be differentiated by the fact that the Mach Number of the fully mixed flows are related in the same manner as are the Mach Numbers across a normal shock wave. One of these states is always representative of a subsonic flow and the other a supersonic flow. Since both solutions represent flows which satisfy the laws of mass flow and energy conservation and the momentum theorum in a channel of uniform cross-section, the physical possibility of achieving these end states must be corroborated by examination of the process in terms of the Second Law of Thermodynamics. Therefore the total entropy change of the flows from the initial to the final state have been determined. It is shown that both solutions correspond to flows which have a positive entropy change in certain ranges of the initial conditions while in other ranges the solution corresponding to a supersonic end state may violate the Second Law of Thermodynamics. Applications of these solutions to the flow through an ejector provide a means for design optimization which results in high thrust augmentating capability at any given flight speed. Author