Nozzles are widely used in the fields of combustion engineering, chemical industry and aerospace, and the most frequent demand for nozzles is in chemical industry applications. For example, air spray pump heads, direct injection nozzles and centrifugal mechanical spray pump heads are used in commonly used spray dryers, among which air spray pump heads are the most widely used.
For a long time, most of the spray pump heads used in combustion engineering or chemical industry mainly use large flow nozzles and work under the conditions of coarse atomization particle size. However, for the newly-developed new surface modification machinery and equipment, it needs to be atomized at less than 10 microns and sprayed in an ultra-fine state.
Whether it is Changyu or a foreign company, the design of ultra-fine air spray pump heads is still based on experience and tests. In theory, the use of supersonic flow atomization is an ideal method to achieve ultra-fine spray pump heads, but so far, there is no scientific theoretical calculation method for such nozzles. Below we use the internal mixed air spray pump head and the three-way gas-liquid-gas critical air spray pump head to conduct the experiment of ultra-fine spray pump head. The internal flow path of the internal mixed air spray pump head is the liquid path, the outer flow path is the sonic atomization gas path, the three-flow path gas-liquid-gas critical air spray pump head middle flow path is the liquid path, and the inner flow path is a subsonic speed The external flow path is a supersonic secondary atomizing gas path.
Superfine spray pump head experimental device and experimental principle
Superfine spray pump head experimental system is divided into water, gas, nozzle experimental gun body, liquid mist test system 4 parts. The atomized particle size distribution is measured with a 2200 Malvern laser particle size analyzer. For the particle size distribution, the R-foot distribution is used. When a ruler is used, the computer can simulate the original data and directly give X and N in the distribution equation. Two parameters. During the experiment of the internal mixed air spray pump head, only the external air path and the liquid path were opened. When the three-stream critical air spray pump head experiment was conducted, the internal and external air paths and the liquid path participated in the work at the same time.
According to the analysis of the existing data, for the air spray pump head, the main factor affecting the fineness of the atomization is the airflow speed. Therefore, the experimental analysis is mainly carried out from four aspects: pore diameter, number of pores, gas-liquid ratio, and air pressure. The nozzle outlet diameter is 2.5 mm, the nozzle liquid hole diameter is 1.0 mm, and the gas-liquid intersection angle is 60 degrees. The spray volume is 30 kg / h.