In the industrial production, the mixing of gas-liquid flow with vapor and gas-solid flow is a very common problem. In the process of the mixing, solid particle-clusters will form, and will have steady radii when the ...In the industrial production, the mixing of gas-liquid flow with vapor and gas-solid flow is a very common problem. In the process of the mixing, solid particle-clusters will form, and will have steady radii when the effect of the gathering of particles is balanced withthat of the breaking of particle-clusters. Then, the population distribution function of size of particles per unit length per unit volume is introduced, and its governingequation is derived on the analogy of the molecular kinetic theory. Finally, when the gas flow is very slow, the expression of steady average radius of particle-clusters is obtained.展开更多
A new quenching process using the cold pyrolysis gas has been proposed for the partial oxidation(POX) of methane to recover the heat. The mixing of hot product gas and cold pyrolysis gas in milliseconds is critical to...A new quenching process using the cold pyrolysis gas has been proposed for the partial oxidation(POX) of methane to recover the heat. The mixing of hot product gas and cold pyrolysis gas in milliseconds is critical to this new approach. Two most widely-used rapid mixing configurations, i.e. the jet-in-cross-flow(JICF) and impinging flow configurations, are compared in terms of mixing and quenching performances using computational fluid dynamics(CFD) coupled with detailed reaction mechanism Leeds 1.5. The mixedness, residence time distribution, temperature decreasing rate and loss ratio of acetylene during the quenching are systematically studied. The results show that the impinging flow has a more uniform mixing and narrower residence time distribution than the JICF.However, the temperature decreasing rate of the mainstream is faster in the JICF than in the impinging flow. The loss ratio of acetylene in the quenching process is 2.89% for the JICF and 1.45% for the impinging flow, showing that the impinging flow configuration is better and feasible for the quenching of POX of methane.展开更多
文摘In the industrial production, the mixing of gas-liquid flow with vapor and gas-solid flow is a very common problem. In the process of the mixing, solid particle-clusters will form, and will have steady radii when the effect of the gathering of particles is balanced withthat of the breaking of particle-clusters. Then, the population distribution function of size of particles per unit length per unit volume is introduced, and its governingequation is derived on the analogy of the molecular kinetic theory. Finally, when the gas flow is very slow, the expression of steady average radius of particle-clusters is obtained.
基金Supported by the National Natural Science Foundation of China(21276135)the Project of Chinese Ministry of Education(113004A)
文摘A new quenching process using the cold pyrolysis gas has been proposed for the partial oxidation(POX) of methane to recover the heat. The mixing of hot product gas and cold pyrolysis gas in milliseconds is critical to this new approach. Two most widely-used rapid mixing configurations, i.e. the jet-in-cross-flow(JICF) and impinging flow configurations, are compared in terms of mixing and quenching performances using computational fluid dynamics(CFD) coupled with detailed reaction mechanism Leeds 1.5. The mixedness, residence time distribution, temperature decreasing rate and loss ratio of acetylene during the quenching are systematically studied. The results show that the impinging flow has a more uniform mixing and narrower residence time distribution than the JICF.However, the temperature decreasing rate of the mainstream is faster in the JICF than in the impinging flow. The loss ratio of acetylene in the quenching process is 2.89% for the JICF and 1.45% for the impinging flow, showing that the impinging flow configuration is better and feasible for the quenching of POX of methane.
