Synthetic Jet Flow Mechanism And Application Technology

Based on the chaotic theory and non-linear system theory, a new active flow control technology-the synthetic jet technology, appeared several years ago. As the key part of synthetic jet technology, the synthetic jet actuator can work without fluid feeding and has momentum flux but no mass flux. Since it only needs electricity when works, it can be controlled easily. Now only a few developed countries are exploring and investigating the synthetic jet technology, and many problems about mechanism and applications need further study. The synthetic jet technology is fresh in our country, it is important to expand the study of the synthetic jet technology and make it into productivity, both in theory and engineering.In this paper, the flow mechanism and the applications of the synthetic jet are studied in theory, numerical simulation and experiment, and this paper prepares for synthetic jet technology used in thrust vector. The main work embodied as follows.(1) Model a biowhig/suction type boundary for synthetic jet actuator, it considers the actuator cavity, exit nozzle and exterior flow field as a single computational region. The model is the most important innovation in this paper, it make computing the whole flow field come true.(2) Based on the model of synthetic jet actuators, the flow field of synthetic jet is simulated by 2D and 3D numerical methods. And finds some significative results by simulating and analyzing. First, the development and evolution of the synthetic jet can be divided into two distinct domains, which compares favorably with the measured data in tests. Second, numerical simulation and qualitative analysis has been done for the synthetic jet flow field in different cases (different phase, amplitude and frequency), and gained many conclusions which are helpful for designing the synthetic jet actuator. Finally, compared with the 2D result, the synthetic jet that 3D numerical simulated has a definite direction. The 3D result, however, has a much smaller fluctuation owing to the span-wise instability which created a breakup of coherent vertical structure into smaller scales, it therefore compares more favorably with the measured data in tests.(3) The adjacent synthetic flow field was numerical simulated and mechanism studied in different cases (phase, amplitude and frequency). It shows that the adjacent synthetic jet flow field is affected by the phase-difference, amplitude and frequency of twoactuators, and the synthetic jet is asymmetric and turning when they are working differently. The main reasons result with the asymmetry and the interaction between the two adjacent synthetic jets, leading to the formation of "low pressure closed circumfluence region", which is also called entrainment field, and the synthetic jet turns to the region where the pressure is lower and the vorticity magnitude is higher.(4) The potential applications of the synthetic jet technology are studied. It shows that the synthetic jet actuators can significantly enhance fuel/oxygen mixing and heat transfer, and the synthetic jet actuators' working condition determines the controlling efficiency. And the technology can also control the vector of a primary jet, the ratio of momentum between the synthetic jet and the primary jet is a main influence factor, and the vectoring control of primary jet is also effected deeply by the position and the frequency of actuators. The characters of the synthetic jet itself and the interaction between the two jets are the main reasons of vectoring control.(5) Designed the synthetic jet actuators and the testing system. Experimented it in quiescent air, and analyzed the actuator's influence factors, such as voltage magnitude and frequency. The results agreed with the conclusions that made from theory analysis and numerical simulation.