Abstract
A supersonic jet of Mach number M = 4.5 in air is produced experimentally at the apex of a miniature 150 × 50 × 5 mm converging section with a 2 × 5 mm opening by the principle of blast wave amplification through focusing. An initial plane blast wave of M = 2.4 in the convergence section is generated by the exploding wire technique. The profile of the convergence section is specially tailored to smoothly transform a plane blast wave into a perfectly cylindrical arc, imploding at the apex of the section. The cylindrical form of the imploding shock delivers maximum shock amplification in the two-dimensional test section and maximum subsequent jet flow velocity behind the shock front. Blast wave propagation in the convergence chamber as well as jet generation through a 2 mm opening at the apex into the adjacent exhaust chamber is optically captured by a high-speed camera using the shadowgraph method. Visualizing the flow provided a distinct advantage not only for obtaining detailed information on the flow characteristics but also for validating the numerical scheme which further enhanced the analysis. Experimental images together with the numerical analysis deliver detailed information on the blast wave propagation and focusing as well as subsequent jet initiation and development. One of the main advantages of the described method apart from being simple and robust is the effective focusing of low initial input energy levels of just around 500 Joules, resulting in production of supersonic jets in a small confined chamber.
Highlights
The main idea of the present study is to use an imploding cylindrical blast wave to generate a high-speed cumulative jet in air behind the converging shock front at the center of implosion propagating through a small orifice into the adjacent exhaust chamber.In recent publications by Maler et al.1 and Shafer et al.2,3 high speed water jets have been generated by an explosion of cylindrical and conical wire arrays
Blast wave propagation in the convergence chamber as well as jet generation through a 2 mm opening at the apex into the adjacent exhaust chamber is optically captured by a high-speed camera using the shadowgraph method
The blast wave generated by the exploding wire technique was accelerated in a chamber with a specially tailored shape of wall boundaries transforming an initially plane blast wave profile into a perfect cylindrical arc and achieving maximum amplification
Summary
The main idea of the present study is to use an imploding cylindrical blast wave to generate a high-speed cumulative jet in air behind the converging shock front at the center of implosion propagating through a small orifice into the adjacent exhaust chamber.In recent publications by Maler et al. and Shafer et al. high speed water jets have been generated by an explosion of cylindrical and conical wire arrays. The main idea of the present study is to use an imploding cylindrical blast wave to generate a high-speed cumulative jet in air behind the converging shock front at the center of implosion propagating through a small orifice into the adjacent exhaust chamber. We use a similar idea of blast wave focusing in air to achieve high energy concentration at the center of cylindrical blast wave implosion which is transformed to a cumulative air jet created at the focal region. The energy released from the capacitor is just around $500 J Another advantage besides the efficient blast wave amplification is a simple and disturbance free access to the center of implosion which is achieved through the geometry of the twodimensional convergence section described
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
