摘要
为优化和扩大旋进旋涡流量计的计量范围,通过CFD方法,采用RNG k-ε湍流模型进行数值模拟并结合试验对150 mm口径的旋进旋涡流量计进行了研究。首先对起旋器入射角为57.5°的流量计进行了非定常数值计算,由于气体速度较低,在数值计算时不考虑气体的压缩性,计算结果能够反映压力损失的实际变化,流量计仪表系数的数值模拟结果与试验值基本吻合。通过试验验证了所采用的数值方法能对流量计的性能进行较好的预测。为进一步分析起旋器入射角度对旋进旋涡流量计压力损失和仪表系数的影响,对3种起旋器入射角度55°、57.5°和60°下的旋进旋涡流量计内部流场进行了三维数值模拟,对比分析了不同入射角下旋进旋涡流量计内部流场分布以及压力损失和仪表系数随流量的变化特性。研究结果表明:流体流经起旋器后压力会迅速下降,旋涡中心的压力相对较低,在喉部以前区域压力沿轴向基本成对称分布;发现起旋器入射角越大,流量计压力损失越大;起旋器入射角度对仪表系数有一定的影响,起旋器入射角越大,仪表系数越大。起旋器入射角度为55°时,旋进旋涡流量计性能最好。
In order to optimize and expand the measure range of the swirl meter with 150 mm diameter, the incident angle of swirler is investigated to improve the performance of swirl meter. The internal flow fields of the swirl meter with different swirler incident angles are numerically simulated using RNG k-ε turbulence model based on CFD （computational fluid dynamics） technique. The pressure loss, instrument coefficient and the distribution of flow field are comparatively analyzed for the swirl meters. First, under the flow rates of 120, 300, 750, 1 200 and 2 100 m3/h, the numerical simulations and experiments are carried out to study the pressure loss characteristics and instrument coefficient of the swirl meter with 150 mm diameter when the incident angle of swirler is 57.5＆#176;. The commercial software Gambit is used to obtain the numerical mesh, and the structured and unstructured grids are used for different regions which take both calculation speed and accuracy into consideration. In the process of calculation, FLUENT software is used for the numerical simulation, and the RNGk-ε turbulence model is adopted considering its better prediction ability in complex unsteady flow condition; besides, the inlet boundary condition is set as velocity inlet, and the outlet boundary condition is set as outflow, which assumes the flow is fully developed. The medium of simulation is air and the density is 1.225 kg/m3; moreover, for the maximum velocity of air in this study is about 33 m/h （when flow rate is 2 100 m3/h） which is much less than Mach 0.3, therefore, the air is considered as incompressible fluid during the simulation. The experiment research is completed by sonic nozzle calibration device under a standard atmospheric pressure and the temperature of 24℃. The numerical results are in good agreement with the experimental ones, and therefore, the numerical method adopted in this paper is proved to be feasible for the research of swirl meter and can save lots of time in the future study. It is appropriate t
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2015年第2期53-58,共6页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金项目(21276241
51106141)
浙江理工大学521人才培养计划项目
浙江省科技计划公益性项目(2014C31116)
关键词
流量计
数值分析
压力
损失
仪表系数
flow meters
numerical analysis
pressure
loss
instrument coefficient
