摘要
针对圆形截面双扭管的工业输水管道中存在流动稳定性和均匀性较差的问题,基于能量梯度理论,采用数值方法,着重研究了雷诺数在6×10^(5)~1.2×10^(6)范围时,0°、90°和180°3种角度双扭管布置方式对圆形截面双扭管内部流动稳定性和均匀性的影响规律。结果表明:相同雷诺数条件下,下游直管段12D范围内,180°双扭管的速度均匀性最好,0°双扭管次之,90°双扭管最差,压力均匀性的变化则刚好相反;90°双扭管在下游弯管处,流体所受合力在周向和径向存在较大分量,导致次流较强,其旋涡角在3种双扭管中最大;在本文计算的下游45D处,90°双扭管的旋涡角仍在10°左右,因而要达到流量计安装要求,还需要更长的直管段;在雷诺数6×10^(5)~1.2×10^(6)范围内,随着雷诺数增大,双扭管内部流动稳定性降低,压力均匀性降低,但是相对应的速度均匀性提升。
For the poor flow stability and uniformity problem of double elbow pipes with circular cross section in industrial water pipeline,based on the energy gradient theory,a numerical simulation method is used to study the influencing rules of three different arrangement modes of the double elbow pipe at angles 0°,90°and 180°on the flow stability and uniformity when Reynolds number ranges from 6×10^(5)to 1.2×10^(6).The results show that under the same Reynolds number condition,the velocity uniformity of 180°double elbow pipe is the best among the three arrangement schemes within 12D downstream length,followed by 0°double elbow pipe,and 90°double elbow pipe is the worst,while the results of the pressure uniformity are just the opposite.The resultant force at the downstream bend of 90°double elbow pipe has larger components in circumferential and radial directions,resulting in strong secondary flow,while its swirling angle is the largest among the three arrangements.At the downstream 45D location of double elbow pipe with 90°,the swirling angle is about 10°,so a longer straight distance is needed to meet the requirements of flowmeter installation.When the Reynolds number is in the range of 6×10^(5)to 1.2×10^(6),the stability of flow and the pressure uniformity decrease with the increase of Reynolds number,but the corresponding velocity uniformity increases.
作者
杨国英
邓清华
何伟
丰镇平
YANG Guoying;DENG Qinghua;HE Wei;FENG Zhenping(Institute of Turbomachinery, Xi’an Jiaotong University, Xi’an 710049, China;Shaanxi Engineering Laboratory of Turbomachinery and Power Equipment, Xi’an Jiaotong University, Xi’an 710049, China)
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2021年第6期102-112,共11页
Journal of Xi'an Jiaotong University
关键词
双扭管
稳定性
均匀性
旋涡角
double elbow pipe
stability
uniformity
swirling angle
