Flame characteristics of horizontal hydrogen jet impinging on a curved wall: An experimental study on extension length and temperature profile

The increasing adoption of hydrogen as a clean energy carrier highlights storage and transportation safety concerns. Jet flames from pipeline leaks can evolve into impingement flames upon impacting adjacent structures, posing significant hazards. This study investigates the flame extension length and temperature distribution of a horizontal hydrogen jet flame impinging on a curved wall, simulating pipeline conditions. The flame extension length increases with leak pressure and nozzle diameter but decreases with nozzle-wall distance. A new correlation coupling unburned fuel and heat release rate predicts the flame extension length based on an elliptical flame shape assumption. The temperature distribution exhibits significant difference in upward and downward directions. The maximum temperature in the impingement zone follows the classic three-region mode, with hydrogen impingement flames showing higher peak temperatures and a longer continuous flame region. Using the plume radius as the characteristic length scale, all temperature data in the impinging zone collapse well.