https://doi.org/10.1140/epjp/s13360-025-06887-9
Regular Article
Numerical investigation of Coanda effect on the vectoring of thermal plasma jet
Faculty of Mechanical Engineering, University of Guilan, Rasht, Iran
a
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Received:
13
May
2025
Accepted:
20
September
2025
Published online:
22
October
2025
Abstract
This study investigates the manipulation of a thermal plasma jet (primary flow) using tangential secondary flow injection to enhance the Coanda effect for fluidic thrust vectoring, a critical advancement for reducing mechanical complexity in aerospace and industrial applications. Through three-dimensional transient simulations of an Argon plasma torch (500 A, 50 SLPM), the intrinsic plasma dynamics are first analyzed, revealing peak temperatures exceeding 30,000 K, velocities over 1000 m/s, and a maximum electric field of 6 × 105 V/m near the cathode. Temporal variations in temperature and velocity are driven by asymmetric arc-root fluctuations, with time-averaged exit values of 9500 K and 700 m/s, validating numerical benchmarks. The novel contribution of this work lies in the systematic investigation of how secondary flow parameters can be used to control jet deflection. Using the k-ω SST turbulence model, it is demonstrated that the Coanda radius ratio (R/D) critically influences deflection sensitivity: at R/D = 4, the thrust angle is increased nonlinearly to 25° for mass flow ratios > 0.107, while smaller radii (R/D = 1–2) exhibit linear responses. Secondary slot height ratios (h/d) are shown to inversely affect deflection; an increase in h/d from 0.125 to 0.25 reduces the thrust angle by 40% due to weakened Reynolds-number-driven pressure gradients. Conversely, the gap ratio between primary and secondary flows (g/d) is found to strengthen the Coanda effect when enlarged to 0.1875, as larger vortices are generated, eliminating dead zones. A reverse Coanda effect is observed below critical mass flow ratios (e.g., 0.0625 for R/D = 4), highlighting geometric and dynamic dependencies.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2025
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
