A Study of Gas-Centered Swirl Coaxial Injectors using X-ray Radiography
Abstract
Gas-centered swirl coaxial injectors, a specific type of airblast atomizer, are of interest in rocket propulsion applications. These applications require good mixing of the liquid and gas to ensure complete combustion within the engine. While strides are being made on the computational front, predictions of the mass distributions achieved with this type of injector remain too costly or too inaccurate for engineering design. There has been, therefore, a reliance on experimental results. Unfortunately, the mass flow rates and the strong gas phase typically encountered in rocket engines create sprays with high optical densities and render the vast majority of optical and laser techniques ineffective. Data has been obtainable through mechanical patternation, but the technique has limitations. Time-gated ballistic imaging has also shown promise in rocket injectors but produces only qualitative information. An x-ray radiographic technique with a high-brilliance x-ray source (Advanced Photon Source) has been applied to these high-optical-density sprays. To achieve this testing a new, mobile flow facility was constructed; this facility simulates the rocket flows using water and nitrogen instead of fuel and oxidizer. The x-ray radiography technique has been able to measure equilvent path length in gas-centered swirl coaxial injectors at a range of typical operating conditions. These results and their implications for gas- centered swirl coaxial injector performance in liquid rocket engines are discussed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2012
- Accession Number
- ADA590090
Entities
People
- Alan Kastengren
- Chris F. Powell
- Malissa D. Lightfoot
- Stephen A. Danczyk
- Stephen Alexander Schumaker
Organizations
- Air Force Research Laboratory