Numerical investigation of the effect of suppressors with different geometries on flow characteristics and sound pressure in fire arms

After firing, it is not possible to reduce the sound pressure level and noise which is emanating from the barrel. However, by assembling the suppressor to the barrel, the sound pressure level which has generated after firing can be minimized. In this study, it has investigated that the effect of suppressors with different geometries on flow characteristics and sound pressure in firearms. It has experimentally and numerically examined that all different cases as follows: without suppressor, hollow suppressor and a suppressor with five baffles that different cross-sections which placed at 20 mm. Calculations were carried out in two-dimensional axisymmetric, transient, compressible conditions. The Ansys Fluent program has been used for numerical modeling. As a result of the calculations, the sound pressure level around the bullet, also the pressure, temperature and velocity change values at different points, were shown in all different positions. When the result examined, it was observed that for the without suppressor condition, the sound pressure level is maximum; for the hollow condition the sound pressure level is decreased and for the different cross-sections suppressor condition the sound pressure level reaches maximum reduction. Furthermore, when evaluating the temperature and velocity changes in different point; it was observed that the temperature change value for the hollow suppressor is lower according to the different cross-sections suppressor. However, it was examined that the temperature is at its lowest level for the without suppressor condition. Regarding with the velocity change values, it was observed that the velocity change in case of different cross-sections suppressor is lower than the hollow suppressor. But, for the without suppressor condition, it was maximum level. These calculations were conducted under conditions with two-dimensional axial symmetry, and the Ffowcs Williams and Hawkings acoustic analogy (FW-H) equations were employed to predict far-field noise levels. Simulations were carried out on suppressor models, both without partition plates and with different sectioned configurations, including helical, perforated, and conical shapes, and were subjected to analysis. The results demonstrated that when a suppressor was not used, the sound pressure level at 0.50 ms and a distance of 1 meters was 165 dB. However, using suppressors with different sectioned designs resulted in an approximate 7% reduction, bringing it down to 154 dB. The findings of this study can serve as a valuable reference for predicting the sound generated at the muzzle of small-caliber pistol systems and optimizing sectioned configurations in suppressors.