Pressure Losses in Simple Dump Combustors
Abstract
Volume limited missiles require a particularly exacting form of component integration. In the integral rocket ramjet (IRR) system the propellant, for the solid rocket booster, is cast directly into the same volume that is used for the ramjet combustor. This study is directed to a better understanding of the pressure losses in dump combustors. Attendant to this study was an effort to simplify methods of predicting compressible flow losses. Application of the incompressible pressure loss factors and equations to compressible problems can lead to serious errors at Mach numbers above 0.3. During this study an equation was derived to predict compressible pressure losses. This equation expresses the pressure loss as a function of the Mach number and a pressure loss factor which is independent of Mach number. Subsequently it was found that the compressible pressure loss factor, called N sub D the dissipation number, was numerically equal to the incompressible pressure loss factor, K sub t, for any given fluid system. The incompressible parameter is basically a function of geometry and Reynolds number and there exists a wealth of data relating to it. Two basic dump combustor designs were selected for testing because of their possible use in missile propulsion. The first was a coaxial circular inlet model, the second a dual side-mounted rectangular inlet model. The measured dissipation numbers were compared to the predicted incompressible parameters and found to be encouragingly similar. The results of this study show, on a preliminary basis, that it may be possible to use the existing incompressible data to predict compressible pressure losses.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1972
- Accession Number
- AD0906402
Entities
People
- Lewis P. Barclay
Organizations
- Air Force Research Laboratory