An Experimental Investigation of Two-Dimensional Thrust Augmenting Ejectors. Part 2.
Abstract
The flow-field within a two-dimensional thrust augmenting ejector has been documented experimentally. Results are presented on the mean velocity field and the turbulent correlations by laser doppler velocimeter, surface pressure distribution, surface temperature distribution, and thrust performance for two shroud geometries. The maximum primary nozzle pressure ratio tested was 3.0. The tests were conducted at primary nozzle temperature ratios of 1.0, 1.8, and 2.7. Two ejector characteristics lengths were identified based on the dynamics of the ejector flow field--a minimum length below which no significant mixing occurs, and a critical length associated with the development of U'V' correlation in the ejector. These characteristic lengths divide the ejector flow field into three distinctive regions: the entrance region where there is no direct interaction between the primary flow and the ejector shroud; the interaction region where there is an increased momentum of induced flow near the shroud surface; and a 'pipe' flow region characterized by an increased skin friction. The effect of the coflowing induced flow shown to produce inside the ejector a centerline velocity that increased over the free-jet data. The normalized turbulent correlations are found to be 25% lower than those in free jets. Effects of pressure ratio on the ejector flow field are small. Present measurements also show that the ejector performance was not influenced by the primary nozzle temperature ratio up to 2.7.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 15, 1984
- Accession Number
- ADA154083
Entities
People
- L. Bernal
- V. Sarohia
Organizations
- Jet Propulsion Laboratory