Experimental Study of the Development of Hydrodynamic Instability in Round Microjet under the Influence of External Acoustic Field with and without Burning

Read more Experimental study of subsonic round micro jets in the diffusion combustion of propane and without combustion at low Reynolds numbers was performed. Development of the jet was as under natural conditions without the acoustic excitation and as acoustic excitation of high intensity (90– 100 dB), frequency of acoustic oscillations was from a few Hz to 6 kHz. The jet flow was realized through the nozzle of round cross-section with a bevel of 45° and a diameter d = 0,45 mm. Blown trough the nozzle mixture of propane-butane previously passed through the evaporator, then through flowmeter (two-channel PR4000B) gas consumption. The studies were performed using Schlieren method based on the IAB-451. The pictures of the shadow visualizations was received, the presence of a developing hydrodynamic instability was found, including the presence of convective forces (by burning). The pictures of diffusion combustion of round propane-butane micro-jet at various modes of combustion – lifted and attached flame were received. It was found that the flame in the diffusion combustion of round microjet at an external acoustic field, exposed to flattening and bifurcation as the air free round microjet, while the source of acoustic oscillations is oriented perpendicular to the jet. The pictures of the diffusion combustion for splitting impact jet by acoustic field were obtained. It was found that in this case on the limits plate two temperature maximum were realized.

Keywords:
shadow pictures, acoustic field, diffusion combustion, round microjet, impact microjets, propane-butane jet. 
УДК 544.452.42

Experimental Study of the Development of Hydrodynamic Instability in Round Microjet under the Influence of External Acoustic Field with and without Burning