發(fā)布時(shí)間：2018-07-27 12:52

【摘要】：在工程實(shí)際中,離心泵變工況運(yùn)轉(zhuǎn)非常常見(jiàn),而在離心泵調(diào)節(jié)工況的諸多方法中,調(diào)速調(diào)節(jié)的節(jié)能優(yōu)勢(shì)是非常明顯的。這就需要我們研究當(dāng)離心泵轉(zhuǎn)速變化時(shí),其內(nèi)部流場(chǎng)和性能參數(shù)的變化情況,以完善現(xiàn)有的半經(jīng)驗(yàn)理論,更好指導(dǎo)實(shí)際生產(chǎn)。同時(shí),對(duì)于一些大功率離心泵,由于實(shí)驗(yàn)室容量、驅(qū)動(dòng)原動(dòng)機(jī)功率等各種條件的限制,不能按規(guī)定轉(zhuǎn)速進(jìn)行全速性能試驗(yàn),只能采用降速試驗(yàn),然后再通過(guò)比例定律將降速測(cè)量參數(shù)換算為規(guī)定轉(zhuǎn)速的參數(shù),這時(shí),比例定律的準(zhǔn)確與否將起著至關(guān)重要的作用,所以有必要對(duì)比例定律進(jìn)行驗(yàn)證,以確定其準(zhǔn)確性和適用范圍,為實(shí)際的應(yīng)用提供參考。 為此,本文選用實(shí)際中使用廣泛的單級(jí)雙吸離心泵為研究對(duì)象,通過(guò)數(shù)值模擬的方法,對(duì)其8個(gè)不同轉(zhuǎn)速所對(duì)應(yīng)的5組相似工況下的內(nèi)部流場(chǎng)及外特性進(jìn)行了對(duì)比研究,并計(jì)算了離心泵調(diào)速調(diào)節(jié)的節(jié)能效果。本文主要的研究成果如下: 1.建立了雙吸離心泵的三維模型,并進(jìn)行了網(wǎng)格劃分,將畫(huà)好網(wǎng)格的模型導(dǎo)進(jìn)Fluent軟件中,對(duì)其進(jìn)行了全流道三維數(shù)值模擬。 2.對(duì)模擬結(jié)果進(jìn)行了后處理,得到了壓水室和葉片正面、背面的壓力和速度分布云圖,通過(guò)對(duì)比壓力云圖發(fā)現(xiàn),在相似工況點(diǎn)上,離心泵壓水室、葉片正面和背面的壓力分布非常相似,近乎完全相同,說(shuō)明本文所研究的泵在相似工況下內(nèi)部流場(chǎng)可以實(shí)現(xiàn)動(dòng)力相似,同時(shí)也說(shuō)明本文的流場(chǎng)計(jì)算是基本正確的;通過(guò)對(duì)比速度云圖發(fā)現(xiàn), 0.7n、0.9n、1n、1.1n、1.2n、1.3n下的相似工況點(diǎn)上壓水室內(nèi)的速度分布近乎完全相同,而在0.6n、0.8n下的相似工況點(diǎn)上,壓水室內(nèi)的速度分布在擴(kuò)散管處和另外6個(gè)相似工況點(diǎn)略有不同,葉片正面和背面的速度分布則規(guī)律非常相似。總體來(lái)看,速度分布在葉片上和壓水室內(nèi)的變化規(guī)律還是高度相似的,說(shuō)明各相似工況點(diǎn)上的流動(dòng)可以滿(mǎn)足運(yùn)動(dòng)相似。 3.通過(guò)數(shù)值模擬的結(jié)果預(yù)測(cè)了泵在不同轉(zhuǎn)速下的性能參數(shù),然后和比例定律的計(jì)算結(jié)果進(jìn)行了比較,發(fā)現(xiàn)在0.6n～1.3n的轉(zhuǎn)速變化范圍以?xún)?nèi),比例定律能較好的預(yù)測(cè)泵的性能參數(shù)隨轉(zhuǎn)速的變化情況,對(duì)本文所選的5組相似工況點(diǎn),比例定律計(jì)算誤差大多在1%以?xún)?nèi),可以滿(mǎn)足實(shí)際需要。 4.分析了調(diào)速調(diào)節(jié)的節(jié)能原理和影響調(diào)速調(diào)節(jié)節(jié)能效果的因素,并計(jì)算了泵在特定管網(wǎng)下的節(jié)能效果。通過(guò)計(jì)算發(fā)現(xiàn),使用調(diào)速調(diào)節(jié)具有良好的節(jié)能效果,隨著調(diào)節(jié)量的增加,調(diào)速調(diào)節(jié)的節(jié)能效果也越明顯,當(dāng)在低流量下運(yùn)行時(shí),節(jié)能率可達(dá)74.58%。
[Abstract]:In engineering practice, it is very common for centrifugal pump to operate under different working conditions, but the energy-saving advantage of speed regulation is very obvious in many methods of centrifugal pump regulation. It is necessary for us to study the variation of internal flow field and performance parameters when the speed of centrifugal pump changes in order to improve the existing semi-empirical theory and better guide the actual production. At the same time, for some high power centrifugal pumps, due to the limitation of laboratory capacity, driving prime mover power and other conditions, the full-speed performance test can not be carried out according to the specified rotational speed. Then through the law of proportion, the parameters of the deceleration measurement are converted to the parameters of the specified rotational speed. At this time, the accuracy of the law of proportion will play an important role, so it is necessary to verify the law of proportion. In order to determine its accuracy and scope of application, to provide a reference for practical applications. In this paper, a single stage double suction centrifugal pump, which is widely used in practice, is chosen as the research object. Through the method of numerical simulation, the internal flow field and external characteristics of five groups of similar working conditions corresponding to 8 different rotational speeds are compared and studied. The energy-saving effect of speed regulation of centrifugal pump is calculated. The main research results of this paper are as follows: 1. The three-dimensional model of double suction centrifugal pump is established, and the mesh is divided. The model of drawing mesh is introduced into Fluent software, and the 3D numerical simulation of the whole flow channel is carried out. 2. After post-processing of the simulation results, the pressure and velocity distributions of the water pressure chamber and the front and back of the blade are obtained. By comparing the pressure cloud images, it is found that at similar working conditions, the centrifugal pump pressure chamber, The pressure distribution on the front and back sides of the blade is very similar, almost identical, which indicates that the internal flow field of the pump studied in this paper can achieve dynamic similarity under similar working conditions, and the calculation of the flow field in this paper is basically correct. By comparing the velocity cloud diagram, it is found that the velocity distribution of the water pressure chamber is almost identical at the similar working condition points under 0.7 ng ~ (0.9n) ~ (-1) n ~ (-1) ~ (-1) N ~ (-1) ~ (-1) ~ (-1) N ~ (-1), but the velocity distribution of the water pressure chamber is slightly different between the diffuser tube and the other six similar working conditions at the similar working condition point under 0.6n ~ 0.8n. The velocity distribution on the front and back of the blade is very similar. As a whole, the variation of velocity distribution on the blade and the water pressure chamber is highly similar, which indicates that the flow at the same working conditions can satisfy the movement similarity. The performance parameters of the pump at different rotational speeds are predicted by the numerical simulation results, and then compared with the calculation results of the law of scale. It is found that the speed of 0.6n~1.3n is within the range of variation. The law of proportion can better predict the variation of pump performance parameters with rotational speed. For the five similar working conditions selected in this paper, the error of the law of proportion calculation is mostly within 1%, which can meet the actual needs. 4. The energy saving principle of speed regulation and the factors influencing the energy saving effect of speed regulation are analyzed, and the energy saving effect of pump under special pipe network is calculated. Through calculation, it is found that the speed regulation has good energy saving effect. With the increase of the regulating quantity, the energy saving effect of the speed regulation is more obvious. When running under the low flow rate, the energy saving rate can reach 74.58.
【學(xué)位授予單位】：蘭州理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2011
【分類(lèi)號(hào)】：TH311

【引證文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 史佩琦;不同葉型的半開(kāi)式葉輪離心泵的數(shù)值模擬與試驗(yàn)研究[D];浙江理工大學(xué);2012年

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本文編號(hào)：2147892