J85-21 Fuel Nozzle Atomization Tests

摘要

Ignition and lean blowout tests were previously conducted at the Naval Air Propulsion Center for a J85-21 combustor using three fuels, JP-5, Suntech A, and NDF. In order to help correlate those test results, Southwest Research Institute conducted atomization tests with a J85-21 fuel atomizer on the same three fuels over a range of air conditions corresponding to air densities used in the combustor tests. The results of those atomization tests are presented in this report. Some significant conclusions from the atomization tests are as follows. The J85-21 combustor uses a dual-orifice pressure-swirl atomizer in which fuel flow is restricted to the primary nozzle for flows below about 3.30 grams, but flows through both the primary and secondary nozzles at higher flows. This results in a complex relationship between average drop sizes and fuel flow rates. At flows below 3.30 g/s, the drop size decrease with increasing fuel flow. As the flow rate increases just above 3.30 g/s, the drop sizes increase as flow begins in the secondary nozzle. At still higher fuel flows the increased pressure drop causes a decrease in drop sizes. Fuel property effects on atomization were significant only at the lowest fuel flow rates, where the NDF and Suntech A exhibited degraded atomization relative to JP-5. Increases in air density tended to decrease the drop-sizes due to increased air friction forces.