本文選題：彎道水流 + 導(dǎo)流墻　； 參考：《山東農(nóng)業(yè)大學(xué)》2014年碩士論文

【摘要】：溢洪道是水庫樞紐工程的重要組成部分,泄槽段是控制段(過堰或閘)與消能防沖設(shè)施段的連接部分。在實(shí)際工程中,由于受地形、地質(zhì)等方面的限制,往往需要在泄槽段設(shè)置彎道。由于彎道的環(huán)流特性,急流通過彎道時(shí),水流流態(tài)惡化。為消除彎道水流的不利影響,設(shè)置導(dǎo)流墻是工程措施之一。本文以模型試驗(yàn)為基礎(chǔ),對(duì)多種組合的彎道水流特性進(jìn)行研究,研究的內(nèi)容和結(jié)論如下： (1)彎道設(shè)置導(dǎo)流墻后水流特性分析 溢洪道彎道設(shè)置導(dǎo)流墻情況下彎道水流特性與不設(shè)導(dǎo)流墻基本一致。溢洪道彎道水流(縱橫向)仍然不均勻,凹岸和凸岸波峰和波谷交替出現(xiàn),存在明顯的菱形波,一直向下游傳播。彎道底坡和軸線半徑對(duì)凹岸水深沿縱向變化有明顯的影響：底坡越陡,凹岸最大水深就越��；彎道軸線半徑越大,凹岸最大水深就越小。彎道各橫斷面凹凸岸水深均有明顯變化,凹岸水深大于凸岸水深,形成明顯的水面橫比降。水流沿橫向有局部的壅高和降低,水流沿橫向不均勻。彎道底坡和彎道軸線半徑對(duì)橫斷面水面差存在影響：彎道底坡越陡,各橫斷面最大水面差越大；軸線半徑越小,各橫斷面最大水面差越大。減小彎道底坡、增大彎道半徑可以減小彎道出口斷面水位差,使彎道下游水流更加均勻。設(shè)置導(dǎo)流墻后,導(dǎo)流墻對(duì)彎道水流進(jìn)行了分割,分割為左右兩個(gè)水槽。在小流量時(shí)(即水位在導(dǎo)流墻以下時(shí))橫比降較小,導(dǎo)流墻兩側(cè)水位有較大水位差,導(dǎo)流墻右側(cè)水深明顯高于導(dǎo)流墻左側(cè)水深；大流量時(shí)(即水位在導(dǎo)流墻以上時(shí))橫比降較大,導(dǎo)流墻兩側(cè)水位大致相平。 (2)彎道設(shè)置導(dǎo)流墻后對(duì)水流的改善效果分析 不同流量、泄槽底坡、彎道軸線半徑、導(dǎo)流墻條數(shù)等對(duì)彎道水流改善效果有明顯的影響。引入了橫斷面水面差降低率和橫斷面水流均勻度評(píng)價(jià)水流改善效果。試驗(yàn)結(jié)果表明流量越小,導(dǎo)流墻對(duì)彎道水流的改善效果越好,即當(dāng)導(dǎo)流墻將彎道水流完全分開時(shí),導(dǎo)流墻對(duì)彎道水流橫斷面水面差的改善效果最好；彎道底坡越緩,導(dǎo)流墻對(duì)彎道水流的改善效果越好；彎道軸線半徑越大,導(dǎo)流墻對(duì)彎道水流的改善效果越好；導(dǎo)流墻條數(shù)越多,導(dǎo)流墻對(duì)彎道水流的改善效果越好。設(shè)置導(dǎo)流墻后流速沿縱向變化更加穩(wěn)定,并且導(dǎo)流墻條數(shù)越多流速沿程越穩(wěn)定。
[Abstract]:Spillway is an important part of reservoir hub project, and the sluice section is the connecting part between control section (through Weir or sluice) and energy dissipation and scour prevention facility. In practical engineering, due to the limitation of topography, geology and so on, it is often necessary to set up bends in the channel section. Because of the circulation characteristics of the bend, the water flow state deteriorates when the jet flows through the bend. In order to eliminate the adverse effect of bend flow, the installation of diversion wall is one of the engineering measures. Based on the model test, this paper studies the flow characteristics of various combinations of bends. The contents and conclusions of the study are as follows: 1) the flow characteristics of spillway with diversion wall are basically consistent with those without diversion wall. The flow of spillway bend (longitudinal and horizontal) is still uneven, the peak and trough of the concave and convex banks appear alternately, and there are obvious rhombic waves which propagate downstream. The bottom slope and axis radius of the bend have obvious influence on the variation of water depth along the longitudinal direction: the steeper the bottom slope, the smaller the maximum water depth of the concave bank, and the smaller the radius of the axis of the bend, the smaller the maximum water depth of the concave bank. The depth of the concave bank is larger than that of the convex bank, which results in obvious water surface ratio drop. The water flow along the lateral side has local blockage and decrease, and the flow along the transverse uneven. The influence of bottom slope and axis radius of bend on the water surface difference of cross section is as follows: the steeper the bottom slope of the bend, the greater the maximum water surface difference of each cross section; the smaller the radius of axis, the greater the maximum water surface difference of each cross section. Reducing the bottom slope of the bend and increasing the radius of the bend can reduce the water level difference at the outlet of the bend and make the downstream flow of the bend more uniform. After setting the diversion wall, the bend flow is divided into two flumes. When the water level is below the diversion wall, the transverse ratio is smaller, the water level on both sides of the diversion wall is larger, and the water depth on the right side of the diversion wall is obviously higher than that on the left side of the diversion wall. At large discharge (that is, when the water level is above the diversion wall), the transverse ratio decreases greatly, and the water level on both sides of the diversion wall is approximately equal. The radius of the axis of the bend and the number of the diversion wall have obvious influence on the improvement effect of the bend flow. The reduction rate of cross section water surface difference and the uniformity of cross section flow are introduced to evaluate the effect of water flow improvement. The test results show that the smaller the flow rate, the better the improvement effect of the diversion wall on the bend flow, that is, when the diversion wall completely separates the bend flow, the better the effect of the diversion wall on the cross-section water surface difference of the bend flow is, and the slower the bottom slope of the bend is, The better the effect of the diversion wall on the bend flow is, the bigger the radius of the axis of the bend is, the better the improvement effect of the diversion wall is on the bend flow; the more the number of the diversion wall is, the better the improvement effect of the diversion wall is on the bend flow. The velocity variation along the longitudinal direction is more stable after setting the diversion wall, and the more the strip number of the diversion wall, the more steady the velocity along the course.
【學(xué)位授予單位】：山東農(nóng)業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TV135.2

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