为探索猪粪小规模条垛式好氧堆肥中气流分布的优化策略,本研究设计了多孔分支曝气管道,并使用Ansys Fluent软件进行了空载及负载条件下的流场仿真分析。研究发现,采用方形主管和配备5个出风孔的支管配置,能实现最优的气流分布均匀性,其...为探索猪粪小规模条垛式好氧堆肥中气流分布的优化策略,本研究设计了多孔分支曝气管道,并使用Ansys Fluent软件进行了空载及负载条件下的流场仿真分析。研究发现,采用方形主管和配备5个出风孔的支管配置,能实现最优的气流分布均匀性,其平均速度为4.88 m s,相对标准偏差为0.519,均匀性指数达到0.776。通过对含水率为37.2%的堆肥物料进行压降试验,确定了其多孔介质参数,包括孔隙率、粘性阻力系数和惯性阻力系数。进一步的流场仿真分析揭示了向上曝气方案相比向下曝气能更有效地减少通风不良区域,从而提升通风效果。为了验证曝气系统的可用性进行了堆肥验证试验,结果表明采用优化的曝气管道结构和向上曝气方案的曝气组,在维持堆体中氧含量在14%~17%的好氧状态下,其堆肥效果明显优于对照组和翻堆组。该研究为改进小规模条垛式好氧堆肥系统的设计与操作提供了理论支撑。展开更多
为了研究博士帽型弯管的流动特性与冲蚀问题,基于Fluent软件描述和模拟实际物理现象的数学和计算框架,选用RNG k-ε模型、DPM离散相模型以及冲蚀速率公式,模拟研究了普通弯管与博士帽型弯管内的冲蚀情况,分析讨论了质量流量、气体流速...为了研究博士帽型弯管的流动特性与冲蚀问题,基于Fluent软件描述和模拟实际物理现象的数学和计算框架,选用RNG k-ε模型、DPM离散相模型以及冲蚀速率公式,模拟研究了普通弯管与博士帽型弯管内的冲蚀情况,分析讨论了质量流量、气体流速、固体颗粒直径对弯管冲蚀磨损的规律。结果显示:相同条件下,博士帽型弯管空腔内气体速度和颗粒速度相比普通弯管较小,颗粒撞击弯管外壁的速度降低,因此博士帽型弯管具有优异的抗冲蚀性能;在特定条件下,流体的流速越高,粒子对弯头的磨损越显著,流速与冲蚀率呈正相关;在同一流速条件下,冲蚀率随着颗粒粒径的增大而逐步上升,最终趋于稳定。In order to study the flow characteristics and erosion problems of doctorial cap pipeline, according to the actual production situation on site, the corresponding physical model was established based on Ansys-Fluent fluid simulation software, and the RNG k-epsilon model, DPM discrete phase model and erosion rate equation were selected to simulate and study the erosion of ordinary pipe and doctorial cap pipe. The laws of mass flow rate, gas flow rate and solid particle diameter on erosion wear of pipe were analyzed and discussed. The findings indicate that, under identical conditions, the gas velocity and particle velocity in the cavity of the Bosch cap bend are smaller than that of the ordinary bend, and the velocity of the particles impacting the shell of the bend is reduced, so the Bosch cap bend has a good anti-erosion effect. Under certain conditions, the faster the fluid velocity is, the more obvious the erosion of particles on the bend, and the flow velocity is positively correlated with the erosion rate. At the same flow rate, the erosion rate increases gradually with the increase of particle size, and finally tends to be stable. The simulation results show that the doctorial cap pipe has strong erosion resistance, and the mass flow rate, gas flow rate and the diameter of solid particles are the main factors affecting the erosion rate of pipeline elbow.展开更多
文摘为探索猪粪小规模条垛式好氧堆肥中气流分布的优化策略,本研究设计了多孔分支曝气管道,并使用Ansys Fluent软件进行了空载及负载条件下的流场仿真分析。研究发现,采用方形主管和配备5个出风孔的支管配置,能实现最优的气流分布均匀性,其平均速度为4.88 m s,相对标准偏差为0.519,均匀性指数达到0.776。通过对含水率为37.2%的堆肥物料进行压降试验,确定了其多孔介质参数,包括孔隙率、粘性阻力系数和惯性阻力系数。进一步的流场仿真分析揭示了向上曝气方案相比向下曝气能更有效地减少通风不良区域,从而提升通风效果。为了验证曝气系统的可用性进行了堆肥验证试验,结果表明采用优化的曝气管道结构和向上曝气方案的曝气组,在维持堆体中氧含量在14%~17%的好氧状态下,其堆肥效果明显优于对照组和翻堆组。该研究为改进小规模条垛式好氧堆肥系统的设计与操作提供了理论支撑。
文摘为了研究博士帽型弯管的流动特性与冲蚀问题,基于Fluent软件描述和模拟实际物理现象的数学和计算框架,选用RNG k-ε模型、DPM离散相模型以及冲蚀速率公式,模拟研究了普通弯管与博士帽型弯管内的冲蚀情况,分析讨论了质量流量、气体流速、固体颗粒直径对弯管冲蚀磨损的规律。结果显示:相同条件下,博士帽型弯管空腔内气体速度和颗粒速度相比普通弯管较小,颗粒撞击弯管外壁的速度降低,因此博士帽型弯管具有优异的抗冲蚀性能;在特定条件下,流体的流速越高,粒子对弯头的磨损越显著,流速与冲蚀率呈正相关;在同一流速条件下,冲蚀率随着颗粒粒径的增大而逐步上升,最终趋于稳定。In order to study the flow characteristics and erosion problems of doctorial cap pipeline, according to the actual production situation on site, the corresponding physical model was established based on Ansys-Fluent fluid simulation software, and the RNG k-epsilon model, DPM discrete phase model and erosion rate equation were selected to simulate and study the erosion of ordinary pipe and doctorial cap pipe. The laws of mass flow rate, gas flow rate and solid particle diameter on erosion wear of pipe were analyzed and discussed. The findings indicate that, under identical conditions, the gas velocity and particle velocity in the cavity of the Bosch cap bend are smaller than that of the ordinary bend, and the velocity of the particles impacting the shell of the bend is reduced, so the Bosch cap bend has a good anti-erosion effect. Under certain conditions, the faster the fluid velocity is, the more obvious the erosion of particles on the bend, and the flow velocity is positively correlated with the erosion rate. At the same flow rate, the erosion rate increases gradually with the increase of particle size, and finally tends to be stable. The simulation results show that the doctorial cap pipe has strong erosion resistance, and the mass flow rate, gas flow rate and the diameter of solid particles are the main factors affecting the erosion rate of pipeline elbow.
