Aspect Ratio Effect on Mach 1.5 Rectangular Jet Mixing

Abstract

An experimental investigation on the mixing characteristics of Mach 1.5 rectangular jet emanating from aspect ratios (ARs) 2 and 3 convergent-divergent nozzles is carried out at nozzle pressure ratios (NPRs) 3, 3.69, 4 and 5, respectively. At overexpanded (NPR 3), correctly expanded (NPR 3.69) and underexpanded (NPRs 4, 5) levels of Mach 1.5 jet, the Pitot pressure measured along the centerline of AR2 and AR3 rectangular jets showed that the influence of aspect ratio on the jet mixing is not as strong as expected. The effect of aspect ratio is noticeable only in the core of both the jets. The core length of AR2 jet is shorter than AR3 jet at all the NPRs, which indicates faster mixing of AR2 jet with ambient fluid as compared to AR3 jet. But after core, the decay of AR2 and AR3 jets in the characteristic decay region remained almost same at all the NPRs except at correctly expanded NPR of 3.69, the AR3 jet decays slightly faster than AR2 jet. For all the cases, the jets have become fully developed together at far downstream location. The pressure profiles taken along major axis and minor axis of Mach 1.5 rectangular jets confirm the faster spreading of AR2 and AR3 jets along minor axis than along major axis. Both the jets are found to switch axes between 8D e to 10D e . The shadowgraph visualization reveals the complex structure of waves present in the major axis and minor axis planes of AR2 and AR3 rectangular jets.

Research of Comprehensive Modeling of Two-Dimensional Vector Nozzle/Actuator Load/Turbofan Engine

“…After long-term theoretical and experimental research of thrust vector technology and the accumulation of several demonstration test projects, at the beginning of the 21st century, the thrust vector technology was successfully applied to the main fighters and stealth aircraft of the Air Force. In the academic field, scholars at home and abroad have done a lot of work in numerical simulation and experiments on the internal flow characteristics of twodimensional vector nozzle [7][8][9][10][11][12][13][14][15]. However, the research on actuator load and vector nozzle/engine integrated model is VOLUME XX, 2023 1 mostly focused on axisymmetric vector nozzle.…”