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PVC三通管水流阻力與流動特征分析
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國家高技術(shù)研究發(fā)展計劃(863計劃)資助項目 (2010AA10A302);國家自然科學(xué)基金資助項目(50909083);高等學(xué)校博士學(xué)科點專項科研基金資助項目(20090204110019)


Flow Resistance and Characteristics of PVC Tee Pipes
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    摘要:

    對DN75×75和DN75×50兩種PVC三通管進行了試驗與數(shù)值模擬研究,結(jié)果表明主管—側(cè)管流向的局部阻力系數(shù)ζ01和主管—直管流向的局部阻力系數(shù)ζ02隨雷諾數(shù)的增大而減小,在雷諾數(shù)大于1.5×105之后基本趨于穩(wěn)定;ζ01、ζ02與分流比呈二次拋物線關(guān)系,通過驗證數(shù)值計算與試驗結(jié)果基本吻合。在此基礎(chǔ)上對5種常見型號的三通管進行了數(shù)值模擬,表明ζ01、ζ02隨管徑比的增大而減小,ζ01的變化幅度遠大于ζ02的幅度,并給出了局部阻力系數(shù)隨分流比變化的定量表達式;流動特征分析可知引起局部水頭損失ζ01的主要原因是水流方向變化的損失和離心力造成的速度分布變化損失,而引起ζ02的主要原因是在較大分流比時水流的剪切和橫向環(huán)流導(dǎo)致直管分岔處上側(cè)的漩渦運動和流速梯度變化損失。

    Abstract:

    Two kinds of tee pipes DN75×75 and DN75×50 were discussed by test methods and numerical simulation. The results showed that local resistance coefficient of main branch to side branch ζ01 and main branch to straight branch ζ02 decreased with increasing Reynolds number and stabilized after the Reynolds number was greater than 1.5×105. The local resistance coefficient ζ01 and ζ02 was correlated with the flow ratio by second order parabolic equations. The numerical simulation results were in good with the experimental data. Through those variables other five kinds of tee pipes were simulated numerically. It showed that the local resistance coefficient ζ01 and ζ02 decreased with increasing diameter ratio, and the variable extent of ζ01 was greater than ζ02. Also the expression equation of local resistance coefficient variation with the flow ratio was given simultaneously. Flow characteristics analysis showed that the main reason caused the local resistance coefficient ζ01 due to the loss of direction changes and velocity distribution caused by centrifugal force, and changes ζ02 was due to the vortex motion and velocity gradient in the straight branch caused by water shearing and transverse circulation in the large flow ratio. 

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石喜,呂宏興,朱德蘭,孫斌,曹彪. PVC三通管水流阻力與流動特征分析[J].農(nóng)業(yè)機械學(xué)報,2013,44(1):73-79,89. Shi Xi, Lü Hongxing, Zhu Delan, Sun Bin, Cao Biao. Flow Resistance and Characteristics of PVC Tee Pipes[J]. Transactions of the Chinese Society for Agricultural Machinery,2013,44(1):73-79,89.

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  • 在線發(fā)布日期: 2012-12-31
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