Schlieren visualization and numerical simulation on gaseous detonation propagation through a bend tube
弯管内爆轰波传播的流场显示和数值模拟

Gaseous detonation propagation through a semi-circle bend tube was experimentally and numerically investigated. The laser schlieren system was employed to obtain the images of detonation front at the different position. The 2nd additive semi-implicit Runge-Kutta method and 5th order WENO scheme were respectively used to discretize the time and space terms of reactive Euler equations. Detailed chemical reaction model was utilized to describe the processes of detonation chemical reactions. 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 rarefaction waves and compressio.n waves, the detonation front is distorted. Due to the shallow curvature of the bend tube, the detonation front is not so seriously distorted and there is no evidence of detonation failure. The leading shock along the concave wall is much stronger than that along the convex wall. The reaction zone along the convex wall is also wider than that along the concave wall. The triple-point number decreases in the process of detonation propagation through the bend tube, and therefore the detonation wave is degenerated. However, it can be recuperated to self-sustaining cellular detonation at the exit section. The computed detonation flow field, cellular pattern and average speed are qualitatively consistent with those from the experiments.