Design ideas and experiments of ultra-fine spray pump heads

Rhenium nozzles are used extensively in the fields of combustion engineering, the chemical industry, and aerospace, and the need for nozzles is most frequent in chemical industry applications. For example, air spray pump heads, direct spray nozzles, and centrifugal mechanical spray pump heads are commonly used in spray dryers. Among them, the air spray pump head is the most widely used.

Most of the time, spray nozzles used in combustion engineering or chemical industry are mainly high-flow nozzles, which work under the condition of coarse atomization particle size. For the new surface modification machinery and equipment that is being developed recently, the atomization degree is less than 10 microns and the superfine state is required to be ejected.

Regardless of whether it is a Changyu company or a foreign company, the design of the ultra-fine air spray pump head is still based on experience and testing. In theory, the use of supersonic airflow atomization is the ideal method to achieve ultra-fine spray pump heads, but so far, there is no set of scientific theoretical calculation methods for this type of nozzle. In the following, we use an internal mixing air spray pump head and a three-flow gas-liquid-gas critical air spray pump head to perform an ultra-fine spray pump head experiment. The internal flow path of the internal mixing type air spray pump head is a liquid path, the external flow path is a sonic atomizing gas path, the three-flow path gas-liquid-gas critical air spray pump head is a liquid path, and the internal flow path is a subsonic gas path. The outer flow path is a supersonic secondary atomizing gas path.

 Experimental device and experimental principle of ultra-fine spray pump head

  The ultra-fine spray pump head experimental system is divided into 4 parts: water, gas, nozzle experimental gun body, and liquid mist test system. The atomized particle size distribution is measured with a 2200 Malvern laser particle size analyzer. The particle size distribution uses the R-foot distribution. When the ruler-one distribution is used, the computer can simulate the original data and directly give X and N in the distribution equation. Two parameters. In the experiment of the internal mixing air spray pump head experiment, only the external air path and the liquid path are opened. When the three-flow path critical air spray pump head experiment is performed, the internal and external air paths and liquid paths participate in the work simultaneously.

According to the analysis of available data, for air spray pump heads, the main factor affecting the atomization fineness is the air velocity. Therefore, experimental analysis is mainly carried out from the aspects of pore diameter, number of pores, gas-liquid ratio, and air pressure. The nozzle outlet diameter is 2.5mm, the nozzle liquid hole diameter is 1.0mm, and the gas-liquid intersection angle is 60 degrees. The spray volume is 30kg / h.

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