Density and Confinement Effects on Mixing Characteristics of an Axisymmetrical CO(2) Jet.
Abstract
This thesis studies the effects of jet density and conefinement on spreading and entrainment rate of axisymmetrical CO2 jet in air. Four tests were conducted to isolate these effects: heated free jet; isothermal free jet; heated confined jet; and isothermal confined jet. The mass flow rate of CO2 was held constant for all tests at 6 kg/hr. Flow visualization studies were also conducted to corroborate results. It was determined that isokinetic sampling for CO2 concentrations is important for obtaining accurate measurements in the jet shear layer for axial distances less than 10 jet diameters. An increase in velocity at the edge of the jet near the entrance plane was noted for the isothermal studies where the density difference between the jet and the surrounding air was significant. Spreading rate for the jets was determined using half width at half maximum criterion. In all four tests it was determined that the scalars of temperature and CO2 spread at the same rate, less than velocity in the initial jet regions and greater than velocity in the initial jet regions and greater than velocity in the fully developed regions of the jet. The heated jet spread slower than the isothermal jet, and the confinement imposed noticeable restrictions on the spreading and entrainment rates of the jet. The heated jet entrained more air than the isothermal jet at the same axial location even though the heated jet had a smaller cross sectional area. In addition, the free jet entrained almost 60% more air than the confined jet.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1985
- Accession Number
- ADA154468
Entities
People
- J. H. Doty
Organizations
- Air Force Institute of Technology