In order to solve the problem of using new nozzle is proposed in fire rescue robot. middle or low water pressure to form fine water mist, a Existing water mist nozzles are basically used for high pressure and in large...In order to solve the problem of using new nozzle is proposed in fire rescue robot. middle or low water pressure to form fine water mist, a Existing water mist nozzles are basically used for high pressure and in large size, complex structure and poor low pressure atomization effect in comparison with requirement of snake-like fire rescue robots. On the basis of comprehensive typical spray noz- zles, a direct spiral double helix converging nozzle （DSDHCN） is proposed, which has the advanta- ges of small volume, light weight, simple structure, and convenient installation. To make the spray nozzle have good performance, and meet the requirements of more efficient fire extinguishing, a nu- merical study is carried out to analyze the internal and external full flow field of nozzle. A gas-liquid two-phase flow is applied to simulate the external full flow field of nozzle with VOF model in fluent software. The simulation results show the real situation of water flow out of the atomization nozzle and the water jet trajectory. Some simulations about middle or low water pressure direct spiral double he- lix converging optimized nozzle have been done in 30bar pressure. The simulation results show that the optimized nozzle structure not only makes the spray droplets have a good cone angle, but also have a sufficient axial velocity,which proves the structure rationality of the proposed optimized nozzle.展开更多
利用有限体积法对三维不可压缩的N-S方程进行离散,对上下表面带有错排间断性楔形肋片且对置的仿螺旋内冷通道进行了数值模拟。网格划分采用非结构化混合网格,湍流模型为kε-两方程模型,在近壁面处采用标准壁面函数法进行处理,速度和压...利用有限体积法对三维不可压缩的N-S方程进行离散,对上下表面带有错排间断性楔形肋片且对置的仿螺旋内冷通道进行了数值模拟。网格划分采用非结构化混合网格,湍流模型为kε-两方程模型,在近壁面处采用标准壁面函数法进行处理,速度和压力的耦合采用S IM PLE算法。计算获得了楔形仿螺旋肋片内冷通道在楔形肋片与主流方向夹角分别为0°、15°、30°时的三维流场分布。结果表明楔形仿螺旋肋片内冷通道的流场结构比较复杂,通道内流体流动达到了预期的仿螺旋流动效果。通道的平均努谢尔数随楔形肋片与主流夹角的增大而呈增大趋势,通道换热强度得到了明显的提高,但同时流动阻力也显著增加。展开更多
基金Supported by the National Natural Science Foundation of China(No.61105086)Self-Planned Task(SKLRS-2010-MS-12)of State Key Laboratory of Robotics and System(HIT)Hubei Province Natural Science Foundation(No.2010CDB03405)
文摘In order to solve the problem of using new nozzle is proposed in fire rescue robot. middle or low water pressure to form fine water mist, a Existing water mist nozzles are basically used for high pressure and in large size, complex structure and poor low pressure atomization effect in comparison with requirement of snake-like fire rescue robots. On the basis of comprehensive typical spray noz- zles, a direct spiral double helix converging nozzle （DSDHCN） is proposed, which has the advanta- ges of small volume, light weight, simple structure, and convenient installation. To make the spray nozzle have good performance, and meet the requirements of more efficient fire extinguishing, a nu- merical study is carried out to analyze the internal and external full flow field of nozzle. A gas-liquid two-phase flow is applied to simulate the external full flow field of nozzle with VOF model in fluent software. The simulation results show the real situation of water flow out of the atomization nozzle and the water jet trajectory. Some simulations about middle or low water pressure direct spiral double he- lix converging optimized nozzle have been done in 30bar pressure. The simulation results show that the optimized nozzle structure not only makes the spray droplets have a good cone angle, but also have a sufficient axial velocity,which proves the structure rationality of the proposed optimized nozzle.
文摘利用有限体积法对三维不可压缩的N-S方程进行离散,对上下表面带有错排间断性楔形肋片且对置的仿螺旋内冷通道进行了数值模拟。网格划分采用非结构化混合网格,湍流模型为kε-两方程模型,在近壁面处采用标准壁面函数法进行处理,速度和压力的耦合采用S IM PLE算法。计算获得了楔形仿螺旋肋片内冷通道在楔形肋片与主流方向夹角分别为0°、15°、30°时的三维流场分布。结果表明楔形仿螺旋肋片内冷通道的流场结构比较复杂,通道内流体流动达到了预期的仿螺旋流动效果。通道的平均努谢尔数随楔形肋片与主流夹角的增大而呈增大趋势,通道换热强度得到了明显的提高,但同时流动阻力也显著增加。
