Experimental Study on the Deflagration to Detonation Transition of Hydrogen Mixture under Elevated Pressure and Temperature Conditions

Article Experimental Study on the Deflagration to Detonation Transition of Hydrogen Mixture under Elevated Pressure and Temperature Conditions Xiao Yu, Long Jin, Linyan Wang, Navjot Sandhu, and Ming Zheng * Department of Mechanical, Automotive and Materials Engineering, University of Windsor, 401 Sunset Avenue, Windsor, ON N9B 3P4, Canada * Correspondence: [email protected] Received: 26 March 2025; Revised: 7 April 2025; Accepted: 14 April 2025; Published: 24 April 2025 Abstract: In this paper, the deflagration to detonation transition (DDT) process of a hydrogen-air mixture is investigated using a small tube with an inner diameter of 11.1 mm. A rapid compression machine (RCM) is utilized to compress the mixture, attaining high pressure and temperature to resemble engine applications. Both piezoelectric pressure transducers and ion sensors are used to detect the flame front, calculating the flame propagation speed. The background absolute pressure before DDT is adjusted from 20 kPa to 810 kPa via a combination of charging pressure and RCM compression, while the background temperature is adjusted from 296 K to 460 K with spark timing adjustment after the compression process of RCM. It is observed that background pressure is an important parameter that decides the existence of a successful DDT process, while background temperature offers a limited contribution to accelerating the flame speed within 1 m tube length.