扫路车吸嘴气固两相流仿真分析及其设计改进
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摘要
应用计算流体力学(CFD)方法对扫路车吸嘴内腔气固两相流进行仿真分析。采用Realizable k-ε湍流模型模拟气相,利用离散相模型追踪固相尘粒运动轨迹。传统吸嘴的模拟结果表明,内腔起主导作用的旋转式气流强度较弱并存在低速涡流区,吸尘效率低。为避免传统吸嘴缺陷,首次提出了后置补气流道、主体空腔呈Y型结构的改进吸嘴。改进吸嘴的流场模拟结果表明:旋转式气流明显加强,形成良好的"龙卷风"作用,能有效提高吸尘效率;另外,补气流道进入的高速气流汇聚于吸管下后方,能阻止尘粒遗漏和有利于尘粒提升进入吸管。尘粒运动追踪结果表明,改进吸嘴的吸尘效率比传统吸嘴提高21.1%。实际路面吸尘试验验证了仿真分析的正确性。试验进一步测得应用改进吸嘴的扫路车有效作业速度比原有提高41.2%,这对提高作业效率和降低单位公里作业油耗具有重要意义。
Simulation analysis of the gas-particle flow through the pickup head of the street sweeper is performed by using the computational fluid dynamics method. In the simulation, Realizable k -ε model and the discrete particle model are adopted to calculate gas flow field and solid particle trajectories, respectively. The simulation results for the conventional pickup head show that the dominant swirl gas flow is weak inside it and the vortex flow with low speed is found at the local region, resulting in the dust particle removal performance is poor. In order to circumvent the detailed troubles, the improved pickup head is developed, which is designed to the shape of Y with the rear airflow passage. The simulation results of the gas flow field for the improved pickup head indicate that the swirl gas flow inside it is strengthened obviously, producing a useful "tornado" effect, which can improve dust removal performance. In addition, the gas flow with high speed, which goes via the rear airflow passage into the bottom of the suction pipe, can prevent the dust particles from going out of the pickup head and also bring the dust particles into the suction pipe more efficiently. The results of tracing the particle trajectories indicate that the dust removal efficiency of the improved pickup head is increased by 21.1%, compared with the conventional one. The simulation analysis has been verified by the dust suction tests carried out in the road surface. It is also found from the tests that the effective working speed of the street sweeper is increased by 41.2% by using the improved pickup head. This is of a great significance in improving the working efficiency and reducing fuel consumption per kilometer.
Simulation analysis of the gas-particle flow through the pickup head of the street sweeper is performed by using the computational fluid dynamics method. In the simulation, Realizable k -ε model and the discrete particle model are adopted to calculate gas flow field and solid particle trajectories, respectively. The simulation results for the conventional pickup head show that the dominant swirl gas flow is weak inside it and the vortex flow with low speed is found at the local region, resulting in the dust particle removal performance is poor. In order to circumvent the detailed troubles, the improved pickup head is developed, which is designed to the shape of Y with the rear airflow passage. The simulation results of the gas flow field for the improved pickup head indicate that the swirl gas flow inside it is strengthened obviously, producing a useful "tornado" effect, which can improve dust removal performance. In addition, the gas flow with high speed, which goes via the rear airflow passage into the bottom of the suction pipe, can prevent the dust particles from going out of the pickup head and also bring the dust particles into the suction pipe more efficiently. The results of tracing the particle trajectories indicate that the dust removal efficiency of the improved pickup head is increased by 21.1%, compared with the conventional one. The simulation analysis has been verified by the dust suction tests carried out in the road surface. It is also found from the tests that the effective working speed of the street sweeper is increased by 41.2% by using the improved pickup head. This is of a great significance in improving the working efficiency and reducing fuel consumption per kilometer.
引文
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[9]Wu B F,Men J L,Chen J.Numerical study on particle removal performance of pickup head for street vacuum sweeper[J].Powder Technology,2010,200(1):934-943.
[10]Shih T H,Liou W W,Shabbir A,et al.A new eddy-viscosity model for high Reynolds number turbulent flows-model development and validation[J].Computer&Fluids,1995,24(3):227-238.
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[12]魏文礼,吕彬,刘玉玲.消能锥阀结构改进的三维数值模拟研究[J].应用力学学报,2013,30(1):109-114.(Wei Wenli,Lv bin,Liu Yuling.Research on the improvement of structure for energy dissipation fixed-cone valve by 3D numerical simulation[J].Chinese Journal of Applied Mechanics,2013,30(1):109-114(in Chinese)).
[13]Melling A.Tracer particles and seeding for particle image velocimetry[J].Measurement Science and Technology,1997,8(12):1406-1416.
[14]Wang B,Xu D L,Chu K W,et al.Numerical study of gas-solid flow in a cyclone separator[J].Applied Mathematical Modelling,2006,30:1326-1342.
[15]Saffman P G.The lift on a small sphere in a slow shear flow[J].Journal of Fluid Mechanics,1965,22:385-400.
[2]谢立杨,杨治林.真空式清扫车吸口速度特性初探[J].西安公路交通大学学报,1997,17(2):98-101.(Xie Liyang,Yang Zhilin.Primary research on velocity characteristic of vacuum vehicle clear inlet[J].Journal of Xi'an Highway University,1997,17(2):98-101(in Chinese)).
[3]欧阳智江,章易程,贾光辉,等.卷边吸尘口流场特性研究[J].机械科学与技术,2013,32(2):362-366.(Ouyang Zhijiang,Zhang Yicheng,Jia Guanghui,et al.Flow properties of dust suction mouth with curled edges[J].Mechanical Science and Technology for Aerospace Engineering,2013,32(2):362-366(in Chinese)).
[4]曾广银,李欣峰,肖田元,等.公路清扫车吸尘系统仿真设计[J].系统仿真学报,2004,16(12):2770-2773.(Zeng Guangyin,Li Xinfeng,Xiao Tianyuan,et al.Simulation for the design of dust suction system of highway sweeper[J].Journal of System Simulation,2004,16(12):2770-2773(in Chinese)).
[5]徐云,李欣峰,肖田元,等.计算流体力学在清扫车仿真分析中的应用研究[J].系统仿真学报,2004,16(2):270-273.(Xu Yun,Li Xinfeng,Xiao Tianyuan,et al.Research on application of computational dynamic fluid in the simulation analysis of highway mechanical sweeper[J].Journal of System Simulation,2004,16(2):270-273(in Chinese)).
[6]朱伏龙,张冠哲,陈杰.真空吸尘车吸尘口的流场仿真和结构优化[J].机械设计与制造,2008(11):50-52.(Zhu Fulong,Zhang Guanzhe,Chen Jie.Flow field analysis and structure optimization of vacuum sweeper suction mouth[J].Machinery Design&Manufacture,2008(11):50-52(in Chinese)).
[7]姜兆文,成凯,龚宇明.吸扫式扫路车吸嘴流场性能分析[J].专用汽车,2012(6):92-97.(Jiang Zhaowen,Cheng Kai,Gong Yuming.Nozzle system performance analysis for suction broom road sweeper[J].Special Purpose Vehicle,2012(6):92-97(in Chinese)).
[8]台冰丰,吴杰灵.清扫车吸尘口结构优化设计[J].专用汽车,2014(4):96-98.(Tai Bingfeng,Wu Jieling.Optimized design of suction mouth of sweeper[J].Special Purpose Vehicle,2014(4):96-98(in Chinese)).
[9]Wu B F,Men J L,Chen J.Numerical study on particle removal performance of pickup head for street vacuum sweeper[J].Powder Technology,2010,200(1):934-943.
[10]Shih T H,Liou W W,Shabbir A,et al.A new eddy-viscosity model for high Reynolds number turbulent flows-model development and validation[J].Computer&Fluids,1995,24(3):227-238.
[11]王福军.计算流体动力学分析[M].北京:清华大学出版社,2004.(Wang Fujun.Computational dynamic fluid analysis[M].Beijing:Tsinghua University Press,2004(in Chinese)).
[12]魏文礼,吕彬,刘玉玲.消能锥阀结构改进的三维数值模拟研究[J].应用力学学报,2013,30(1):109-114.(Wei Wenli,Lv bin,Liu Yuling.Research on the improvement of structure for energy dissipation fixed-cone valve by 3D numerical simulation[J].Chinese Journal of Applied Mechanics,2013,30(1):109-114(in Chinese)).
[13]Melling A.Tracer particles and seeding for particle image velocimetry[J].Measurement Science and Technology,1997,8(12):1406-1416.
[14]Wang B,Xu D L,Chu K W,et al.Numerical study of gas-solid flow in a cyclone separator[J].Applied Mathematical Modelling,2006,30:1326-1342.
[15]Saffman P G.The lift on a small sphere in a slow shear flow[J].Journal of Fluid Mechanics,1965,22:385-400.