【作者】 戚玉彬；

【导师】 吕宏兴；

【作者基本信息】 西北农林科技大学 ， 农业水土工程， 2007， 硕士

【摘要】 本文在总结灌区量水技术的基础上,指出了目前量水设施普遍存在的问题,并对一种新型的流线型量水槽—机翼形量水槽进行试验研究。为了分析论证其量水性能的优劣和应用的可行性,本文选取了不同类型的机翼形量水槽在矩形渠道上进行试验,取得了初步的研究成果。通过试验和量纲分析,得到了矩形渠道机翼形量水槽在自由出流状态下的流量公式,无量纲式较好地反映了该量水槽不同收缩比时相对临界水深hk/bC与相对上游水深h/bC之间的指数函数关系.根据量纲分析建立的流量公式满足量纲和谐性,且流量公式简明实用,测流精度较高,流量的平均相对误差为0.47%。在底坎式机翼形量水槽时,平均相对误差为1.44%.机翼形量水槽的临界淹没度较高,临界淹没度随着收缩比和流量的变化而变化。在试验收缩比的范围内,临界淹没度的变化范围为0.77～0.89,均值可达0.84,能在较大范围内保证机翼形量水槽在自由出流状态下工作。机翼形量水槽的水头损失不大,水头损失约占上游总水头的14%左右。试验表明机翼形量水槽的佛汝德数Fr与流量和收缩比有关,佛汝德数Fr随流量和收缩比的增大而增大。在试验收缩比的范围内,机翼形量水槽的佛汝德数Fr均小于0.35,完全可以满足保证量水槽的测流精度。另外,机翼形量水槽对水流的阻力小,槽前壅水高度一般不超过10cm。通过对机翼形量水槽在矩形渠道上的试验和对量水性能进行分析,机翼形量水槽具有测流精度较高,流量计算公式简捷,水流阻力小,临界淹没度较高,水头损失不大,结构简单、测流幅度大等优点。初步研究表明:机翼形量水槽是适合矩形渠道上测流的新型量水设备,有较好的推广应用前景。更多还原

【Abstract】 The text pointed out the problem of current water-measuring device on the base of summarizing measuring water technology in irrigation district, and did research on a new stream-lined flume—airfoil-shaped measuring flume. In order to analyse its adv-antages and disadvantages of water-measuring performance and the applied feasibility,The text selected 3 kinds of different contract ratios airfoil-shaped measuring flume a-nd carried on great trial research in rectangular channel, and obtained the certain rese-arch result.The flow formula of airfoil-shaped measuring flume is established in free flow inrectangular channel by experiment and the dimensional analysis. The dimensionless expression showed perfectly the exponential function relationship about relative critical depth and relative upstream water depth of airfoil-shaped measuring flume in different contract ratios. The discharge formula established by the method of dimensional analysis is harmonious. The formula is simple, clear and practical, and have highly precision of flow measurement, the average relative error is only 0.47%.The average relativeerror is only 1.44% when airfoil-shaped measuring flume have a still.Airfoil-shaped measuring flume has highly critical submergence. the submergence changes with changing contract ratio and discharge. With the range of experimental contract ratio, the submergence is between 0.77 and 0.89. the average critical submergence is 0.84,which ensure measuring flume to work in free flow at a great range. The airfoil-shaped measuring flume water head loss isn’t higher, and the water head losing has 14% of the total head of water. The experimental results showed that the Froude number related to discharge and contract ratio, the Froude number rises with increasing discharge and contract ratio. The Froude number of airfoil-shaped measuring flume is below 0.35, according with the request of the flow measurement of open channel. In addition, Resistance to water-flow of airfoil-shaped measuring flume is small, The back water height shall not exceed 10cm.According to experiment in rectangular channel and analysis of water-measuring performance about airfoil-shaped measuring flume, airfoil-shaped measuring flume have several advantages over other form of flume: higher precision of flow measurement, simple、clear and practical discharge formula, less resistance to water-flow, higher critical submergence, smaller water head loss, simple structure. Premilinary syudy showed that airfoil-shaped measuring flume is a new type water-measuring device , which fit to measure flow in rectangular channel, and endowed with a good prospect of application and extension.更多还原