Jet performance and structural optimization of nozzle used in well-controlled ignition device based on response surface method

The well control ignition device is the critical equipment for eliminating combustible and toxic gases within the casing during a well blowout. The jet performance of its nozzle directly determines the safety and reliability of ignition. To enhance the jetting performance of this nozzle and optimize its structure, this study systematically investigated the influence mechanism of the structure of the conical nozzle and the key parameters of the jetting medium on the jetting performance. Based on computational fluid dynamics (CFD) simulations and jet theory analysis, it was determined that the average velocity of the nozzle outlet is the key factor determining the spray range, while the velocity attenuation along the path dominates the stability of the jet. Through single-factor analysis, the nozzle contraction angle A, diameter D, and length L were identified as the core optimization variables. Multi-objective optimization was performed using a response surface method based on a Kriging model. Results demonstrate that the optimized nozzle outlet average velocity increased from 40.07 m/s to 43.7 m/s, while the velocity attenuation along the path decreased significantly from 1.53 m/s to 0.048 m/s. It effectively enhances the nozzle’s spray range and jet stability.