摘要
针对标准孔板钝化问题,提出了在线识别算法,并给出具体方案。首先利用Fluent流场仿真软件对孔板正常工况和钝化工况进行建模与仿真计算,与国家标准对比验证了仿真的正确性。为实现识别算法,在孔板法兰取压点P1、P2后方,再增设一取压点P3,计算3个取压点中两组差压的比值,得到差压比值因子η,因子η反映了钝化的孔板下游流场相对于正常工况时的畸变程度,即η反映了钝化程度。通过分析仿真计算结果确定了P3取压点的最佳选取位置,并进一步得出η与钝化程度的计算式。通过计算式,可以实现钝化的在线识别与流量测量值修正。现场实流实验验证了识别算法的有效性,相对于国家标准,算法的误差在±1.0%以内。
Online identitication of orifice bluntness was put forward, and specific solutions was given. Orifice discharge coefficient of CFD simulation on normal condition and bluntness conditions were compared with GB/T 25446--2008 to verify the validity of the simulation. To achieve the identification, in the rear of the flange pressure points （P1 , P2） another pressure point P3 was installed and the differential pressure ratio factor （η） was calculated. The factor reflected the degree of distortion of orifice plate flow field relative to the normal condition, which was the ratio factor indirectly reflected the degree of bluntness. The best position of pressure points P3 was determined by the analysis of simulation results, and the experience formula about the ratio factor with bluntness was further concluded. Through the formula, online identification of bluntness could be realized. The effectiveness of the identification algorithm was verified through real flow experiments. The error of calculated value was within ± 1.0% for sharpness correction coefficient （bk） , which proved that the algorithm was practicable in engineering.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2014年第6期317-323,共7页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家自然科学基金资助项目(60974118)
关键词
孔板流量计
入口边缘钝化
在线识别
差压比值因子
流场畸变
Orifice meter Inlet edge bluntness Online identification Differential pressure ratio factor Flow field distortion
