Study on Prediction and Optimization of Long-range Water Mist Projection

The development of a long-distance water mist projection device is essential for mitigating emergencies like fires, explosions, chemical leaks, and dust contamination. Currently, there is a lack of theory to predict the spray range under the effect of fan operating parameters and duct structures, which results in the blindness of long-distance water mist projection device design. By integrating fluid dynamics theory, classical jet theory, and real operational data, a semi-empirical model is developed to predict the jet range and analyze the velocity distribution of the projection device. This model can be used to identify the key factors affecting characteristics of multiphase jet and optimize the alignment between the fan and air duct. Subsequently, a long-distance water mist projection device was manufactured and tested. At a range of 30.2 m, a large-scale transformer fire with a heat release rate between 81.31 and 124.56 MW was extinguished within 3 min using the proposed device. This comprehensive study may aid the development of long-distance axial airflow-inducing water mist devices and their applications in emergency response scenarios.