下料方式和流量分配对D4合成SiO2的影响

Effect of feeding mode and flow distribution on SiO2 synthesis from D4

燃烧器设计和流量控制对燃烧稳定性、SiO2生成、疏松体品质和关键组分分布有重要影响。该文通过对八甲基环四硅氧烷(OMCTS,D4)制备SiO2疏松体过程的数值研究,分析了不同下料方式,以及D4和氧气流量分配对SiO2生成效率和沉积面上关键组分分布的影响。结果表明:采用多点下料方式可以明显提高SiO2生成率和沉积均匀性;内外D4进口流速接近时,SiO2生成率较高,并且OH浓度有所降低;根据D4质量流量分配对氧气进口流量分配进行调整,能够提高SiO2生成率,但相应的OH浓度也有所增加;但在保持D4质量流量不变的情况下,采用多点下料,导致D4进口速度降低,一定程度上降低了沉积效率。采用多点下料时,可以考虑适当提高D4流量,控制火焰温度,有利于提高SiO2生成和沉积效率。

Burner design and flow rate control strongly impact combustion stability,SiO2 generation,soot quality,and key flue gas components.This paper presents a numerical study of SiO2 soot synthesis by the CVD method with octamethylcyclotetra-siloxane(also called‘OMCTS’or‘D4’)as the precursor.The study investigates the effects of various feeding modes and D4 and oxygen mass flow rates on the SiO2 generation efficiency and the distribution of key components on the surface.The SiO2 generation rate and deposition uniformity can be significantly improved by using the multi-point feeding mode which increases the SiO2 generation rate and reduces the OH concentration even with similar D4 inlet velocities.Proper control of the oxygen flow rate relative to the D4 mass flow rate improves the SiO2 generation rate,but also increases the OH concentration.The multi-point feeding mode with the same D4 mass flow rate can reduce the D4 inlet velocity with then reduces the deposition efficiency some.Multi-point feeding with the proper increased D4 flow rate and flame temperature control improves the SiO2 generation rate and deposition efficiency.