Schlieren visualization and numerical simulation on gaseous detonation propagation through a bend tube

Gaseous detonation propagation through a semi-circle bendtube was experimentally and numerically investigated. The laser schlierensystem was employed to obtain the images of detonation front at thedifferent position. The 2nd additive semi-implicit Runge-Kutta methodand 5th order WENO scheme were respectively used to discretize the timeand space terms of reactive Euler equations. Detailed chemical reactionmodel was utilized to describe the processes of detonation chemicalreactions. The contours of pressure, temperature, OH mass fraction,numerical cellular pattern and average detonation speed were obtained.Experimental and numerical results show that, influenced by the rarefactionwaves and compression waves, the detonation front is distorted. Due to theshallow curvature of the bend tube, the detonation front is not so seriouslydistorted and there is no evidence of detonation failure. The leading shockalong the concave wall is much stronger than that along the convex wall. Thereaction zone along the convex wall is also wider than that along theconcave wall. The triple-point number decreases in the process of detonationpropagation through the bend tube, and therefore the detonation wave isdegenerated. However, it can be recuperated to self-sustaining cellulardetonation at the exit section. The computed detonation flow field, cellularpattern and average speed are qualitatively consistent with those from theexperiments.