School of Emergency Management and Safety Engineering, China University of Mining and Technology (Beijing), Beijing 100083, PR China
A reliable agent addition control is crucial for the foam technology that is prevalent in many industrial fields. The objective of this paper is to reveal the precise quantitative control mechanism and distinctive performance of cavitation jet. The cavitation evolution suction process is analyzed by the vapor appearance order defined. A 5-6 mm vapor-liquid transition interface is found in the cavitation jet with a remarkable mutation in fluid pressure, density and velocity. The vapor region in the jet device decreases and the maximum vapor volume fraction declines from 96.4% to 0 as the pressure ratio increases. The precise quantitative control is realized by the cavitation jet at the negative pressure less than -87 kPa in the suction port. The absorption amount decreases with the absorbed liquid viscosity increasing and a various level of precise quantitative control is achieved by the orifice plate area. The relation between the absorption amount and plate area is quadratic curve. Furthermore, the dust suppression practical was successfully conducted in a coal bunker to verify the effectiveness of foam technology using cavitation jet. Based on the above contribution, it is believed that the proposed precise quantitative control method has a strong applicability and popularization in industrial control field.