转速变化对离心泵性能影响的数值模拟研究及调速调节节能分析
发布时间：2018-07-27 12:52
【摘要】：在工程实际中,离心泵变工况运转非常常见,而在离心泵调节工况的诸多方法中,调速调节的节能优势是非常明显的。这就需要我们研究当离心泵转速变化时,其内部流场和性能参数的变化情况,以完善现有的半经验理论,更好指导实际生产。同时,对于一些大功率离心泵,由于实验室容量、驱动原动机功率等各种条件的限制,不能按规定转速进行全速性能试验,只能采用降速试验,然后再通过比例定律将降速测量参数换算为规定转速的参数,这时,比例定律的准确与否将起着至关重要的作用,所以有必要对比例定律进行验证,以确定其准确性和适用范围,为实际的应用提供参考。 为此,本文选用实际中使用广泛的单级双吸离心泵为研究对象,通过数值模拟的方法,对其8个不同转速所对应的5组相似工况下的内部流场及外特性进行了对比研究,并计算了离心泵调速调节的节能效果。本文主要的研究成果如下: 1.建立了双吸离心泵的三维模型,并进行了网格划分,将画好网格的模型导进Fluent软件中,对其进行了全流道三维数值模拟。 2.对模拟结果进行了后处理,得到了压水室和叶片正面、背面的压力和速度分布云图,通过对比压力云图发现,在相似工况点上,离心泵压水室、叶片正面和背面的压力分布非常相似,近乎完全相同,说明本文所研究的泵在相似工况下内部流场可以实现动力相似,同时也说明本文的流场计算是基本正确的;通过对比速度云图发现, 0.7n、0.9n、1n、1.1n、1.2n、1.3n下的相似工况点上压水室内的速度分布近乎完全相同,而在0.6n、0.8n下的相似工况点上,压水室内的速度分布在扩散管处和另外6个相似工况点略有不同,叶片正面和背面的速度分布则规律非常相似。总体来看,速度分布在叶片上和压水室内的变化规律还是高度相似的,说明各相似工况点上的流动可以满足运动相似。 3.通过数值模拟的结果预测了泵在不同转速下的性能参数,然后和比例定律的计算结果进行了比较,发现在0.6n～1.3n的转速变化范围以内,比例定律能较好的预测泵的性能参数随转速的变化情况,对本文所选的5组相似工况点,比例定律计算误差大多在1%以内,可以满足实际需要。 4.分析了调速调节的节能原理和影响调速调节节能效果的因素,并计算了泵在特定管网下的节能效果。通过计算发现,使用调速调节具有良好的节能效果,随着调节量的增加,调速调节的节能效果也越明显,当在低流量下运行时,节能率可达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.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH311
本文编号：2147892
[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.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH311
【引证文献】
相关硕士学位论文 前1条
1 史佩琦;不同叶型的半开式叶轮离心泵的数值模拟与试验研究[D];浙江理工大学;2012年
，本文编号：2147892
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