Spray field characteristics and the effect of spray-local exhaust ventilation on the control of high-temperature buoyant jets

Abstract

Process equipment limitations resulted in constraints on the location of the exhaust hood, which in turn caused escape of high-temperature buoyant jets. In response to this situation, spray system is installed as an auxiliary measure to improve the control effect by spray cooling and weakening the momentum. However, the correlation between spray parameters and its atomization characteristics in high temperature ambient is not clear, reasonable spray parameters directly affect the performance of spray-local exhaust ventilation (SLEV). In this study, we discuss the spray field characteristics under the action of high-temperature buoyant jets, the effects of exhaust and spray parameters on the capture efficiency of SLEV, combined with orthogonal test to get the optimization order. Influences discussed include: exhaust velocity, spray pressure, and nozzle hole diameter. The results showed that SLEV provides superior control of high-temperature buoyant jets, up to two times that of the local exhaust ventilation (LEV). Compared to nozzle hole diameter, the spray pressure significantly effects on spray field characteristics. Under high-temperature buoyant jets conditions, the statistical mean diameter obeys a power function relationship with spray pressure, and the capture efficiency was 75% as the spray pressure of 2.0 MPa and nozzle hole diameter of 1.8 mm. The factors affecting the performance of SLEV was found to be exhaust velocity > spray pressure > nozzle hole diameter by range analysis. The research results are expected to contribute to the optimization and enhancement of the SLEV.