Demonstration of Sanal Flow Choking and/or Streamtube Flow Choking in 3D Reacting Flows Causing Detonation and Explosions

Abstract

The decisive demonstration of the roots and aftermaths of the boundary layer persuaded flow choking (Sanal flow choking) and/or streamtube flow choking in non-reacting flows (V.R.S.Kumar et al., Physics of Fluids, 34(4), 2022, https://aip.scitation.org/doi/10.1063/5.0086638) and humans circulatory system (V.R.S.Kumar et al., Physics of Fluids, 34(10), 2022, https://aip.scitation.org/doi/10.1063/5.0105407) sheds lights on the diagnostic investigation of deflagration-to-detonation-transition (DDT) and asymptomatic explosions in internal and free external flows. An exact mathematical model derived from the compressible flow theory is reproduced herein to forecast the lower-critical-detonation-index (LCDI) in reacting flow systems (V.R.S.Kumar et al., Scientific Reports, 2021, https://www.nature.com/articles/s41598-021-94450-8). The closed-form analytical model reveals that comparatively high-viscosity and low heat capacity ratio of the leading species are prone to Sanal flow choking and/or streamtube flow choking in both internal and external flows. The three-dimensional (3D) and two-dimensional (2D) in silico reacting flow simulation results show that Sanal flow choking and sonic fluid throat effect assert the threshold condition of detonation and explosions. In silico studies further reveal that relatively high and low viscosities are susceptible for flow choking in reacting flow systems. The boundary layer blockage factor causing flow choking will be enhanced due to the significant flow turbulence because of high Reynolds number at a relatively low viscosity. We concluded that the undesirable shock wave followed by pressure-overshoot leading to detonation and/or explosion often observed in reacting flow systems due to Sanal flow choking and/or streamtube flow choking can be annulled judiciously by contravening the sonic fluid throat effect by retaining the total-to-static pressure ratio unceasingly lesser than the LCDI. The concept of sonic fluid throat effect reported herein reconfirms the Chapman–Jouguet (1899) condition of detonation propagation and ceases. In silico results presented herein ascertained that the theoretical discovery of Sanal flow choking and/or streamtube flow choking is a “paradigm shift” in predicting physics of detonation chemistry. Briefly, the theoretical discovery of the phenomenon of sonic fluid throat effect due to streamtube compression (pinching) in yocto to yotta scale reacting flow systems and beyond encompasses disruptive technologies at the cutting edge to elucidate century-long unanswered research questions in fundamental science and it further sheds light on exploring the basic cause(s) of detonation, environmental and supernova explosions.