高压小空间内大流量雾化喷嘴研究开发与工程验证

发布时间：2018-10-15 10:29

【摘要】：高压小空间中的大流量液体雾化问题是工业实践提出的需求。总结分析了关于液体雾化的经典理论和常用雾化方法,提出了同种液体双(多)股射流撞击雾化的设想,对其性能进行了研究分析,进而在工业装置中予以验证。实验和数值模拟表明,增加压力或降低气液质量流量比可以提高内混式气体辅助雾化喷嘴的出力,但喷嘴的雾化性能随之恶化。借鉴固体挡槽雾化和外混式气体辅助雾化的工作原理,提出了双(多)股同种射流的液-液撞击雾化喷嘴概念,利用简化模型数值模拟验证了该设想的可行性,进而详细分析了其喷嘴的工作原理和结构实现方法,并进行了系统的实验研究。实验结果表明,射流撞击具有良好的雾化效果;流量系数均在0.55~0.8范围内,与喷孔的长径比有关。条件雾化角100α随着出力的增大略有上升;雾化角的大小跟射流夹角密切相关,与孔径关联不大;射流数量的增加有使雾化角下降的趋势。双(多)股射流的液-液撞击雾化喷嘴随着射流夹角的减小,雾化液滴平均直径dsmd增大,均匀系数m减小。随着同点撞击射流数量的增加,雾化液滴平均直径dsmd有所增大,均匀系数m减小。雾化孔径的增加有使液滴平均粒径增大的趋势,但影响不太显著。进而建立了物理模型,理论分析结果与实验得出的数据具有较好的一致性。利用双股射流撞击雾化,可以通过组合来实现小空间内大流量液体雾化,提出了基于双(多)股射流撞击雾化喷嘴的设计准则。分析了压力对雾化的影响,将实验结果外推到高压条件下,在压力为20.0MPa的甲铵冷凝器的混合器上和水溶液全循环法尿素工艺的合成塔中对基于双股射流撞击雾化喷嘴的组合结构实现和雾化效果进行了工业验证,使用效果反映出本文开发的基于多股射流撞击雾化喷嘴的良好性能。在此过程中,整理提出了20.0MPa情况下的NH3 CO2系统相图,建立了尿素合成系统模型,计算结果与实际运行数据非常吻合。
[Abstract]:The problem of large flow liquid atomization in high pressure and small space is the requirement of industrial practice. The classical theory and common atomization methods of liquid atomization are summarized and analyzed. The assumption of the same liquid double (multi-strand) jet impingement atomization is put forward, and its performance is studied and analyzed, which is verified in the industrial plant. The experiment and numerical simulation show that increasing the pressure or decreasing the mass flow ratio of gas and liquid can increase the output force of the gas assisted atomizing nozzle, but the atomization performance of the nozzle will deteriorate. The concept of liquid-liquid impingement atomizing nozzle with double (multiple) strands of the same jet was proposed by referring to the working principle of solid baffle atomization and external mixed gas-assisted atomization, and the feasibility of the idea was verified by numerical simulation of simplified model. Then, the working principle and structure realization method of the nozzle are analyzed in detail, and the systematic experimental research is carried out. The experimental results show that the jet impingement has a good atomization effect, and the flow coefficient is in the range of 0.55 ~ 0.8, which is related to the ratio of length to diameter of the jet hole. The atomization angle 100 伪 increases slightly with the increase of the output force, the atomization angle is closely related to the jet angle and has little relation with the aperture, and the increase of the number of jets has the tendency of decreasing the atomization angle. With the decrease of the jet angle, the average diameter of droplet dsmd increases and the uniform coefficient m decreases for the liquid-liquid impingement atomizing nozzle with double (multiple) jets. With the increase of the number of impinging jets at the same point, the average diameter dsmd of atomized droplets increases and the uniformity coefficient m decreases. The increase of atomization pore size tends to increase the average particle size of droplets, but the effect is not obvious. Furthermore, the physical model is established, and the theoretical analysis results are in good agreement with the experimental data. The large flow liquid atomization in small space can be realized by the combination of double jet impingement atomization. The design criterion based on double (multiple) jet impingement atomizing nozzle is proposed. The influence of pressure on atomization is analyzed, and the experimental results are extrapolated to high pressure conditions. In the mixer of ammonium methylammonium condenser with pressure of 20.0MPa and in the synthesis tower of urea process with aqueous solution, the realization of the combined structure and the atomization effect based on the two-strand jet impinging atomizing nozzle were carried out. The effect reflects the good performance of the multi-jet impingement atomizing nozzle developed in this paper. In this process, the phase diagram of NH3 / CO2 system under 20.0MPa is presented, and the urea synthesis system model is established. The calculated results are in good agreement with the actual operation data.
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TQ027.32

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