CAJ | 학술논문

为探究轴流泵叶轮导水锥的设计方法，揭示导水锥流场的内部流动特性。基于三维不可压缩流体的雷诺平均N-S方程和k-ε湍流模型，结合典型的收缩曲线，设计了维多辛斯基式、五次方曲线式、双三次方曲线式等5种导水锥。利用Fluent 软件对各型导水锥进行三维流场计算，分析了导水锥流道的流动特性，归纳了导水锥流场的3个流动部分以及流场轴面的速度分布规律。总结了轴向速度分布均匀度、加权平均偏流角随导水锥收缩型面的变化规律。分析各型导水锥水力损失发现：不同型式导水锥水力损失不同，直锥式导水锥损失略小，其他型式的导水锥水力损失相近。对流场均匀性相比较得出：在导水锥流场急剧收缩的断面上，轴向速度分布均匀度降低，速度加权平均偏流角和径向速度梯度增大。导水锥出口段收缩越平缓，整流能力越出色。综合考虑轴向速度均匀度和速度偏流角等指标，维多辛斯基式导水锥的整流能力最优，出口流场均匀性较好。当导水锥长度为叶轮外径的0.25～0.8倍时，导水锥长度增加，水力损失减小，导水锥出口流场品质提升。结合工程实际应用，给出导水锥长度最优取值范围为叶轮外径的0.5～0.6倍。
위탐구축류빙협륜도수추적설계방법，게시도수추류장적내부류동특성。기우삼유불가압축류체적뢰낙평균N-S방정화k-ε단류모형，결합전형적수축곡선，설계료유다신사기식、오차방곡선식、쌍삼차방곡선식등5충도수추。이용Fluent 연건대각형도수추진행삼유류장계산，분석료도수추류도적류동특성，귀납료도수추류장적3개류동부분이급류장축면적속도분포규률。총결료축향속도분포균균도、가권평균편류각수도수추수축형면적변화규률。분석각형도수추수력손실발현：불동형식도수추수력손실불동，직추식도수추손실략소，기타형식적도수추수력손실상근。대류장균균성상비교득출：재도수추류장급극수축적단면상，축향속도분포균균도강저，속도가권평균편류각화경향속도제도증대。도수추출구단수축월평완，정류능력월출색。종합고필축향속도균균도화속도편류각등지표，유다신사기식도수추적정류능력최우，출구류장균균성교호。당도수추장도위협륜외경적0.25～0.8배시，도수추장도증가，수력손실감소，도수추출구류장품질제승。결합공정실제응용，급출도수추장도최우취치범위위협륜외경적0.5～0.6배。
Axial flow pumps have advantages of large capacity and low head and the impeller is an important component of axial-flow pump. Guide cone is usually installed on the top of impeller and its appropriate design can enhance flow quality of pump inlet, lower turbulivity, make velocity steady, and so on. To meet with engineering demands, find feasible design and investigate the internal flow characteristics of guide cone, we designed different types of guide cones installed on the impeller. Based on three dimensional incompressible Navier-Stokes equation andk-ε turbulent model, SIMPLEC algorithm was applied to solve a discretization governing equation, five different types of guide cones were designed with contraction curves such as Witozinsky, Bicubic, Fifth degree polynomial curves. The CFD method was used to simulate 3D flow field of guide cone. In order to verify the feasibility of simulation models, the guide cones were installed on the impeller and the simulated head and efficiency values were obtained using simulation method same as the flow field simulation of guide cone. Meanwhile, a laboratory test was performed on a DN200 test bench to measure the pumping head, discharge, and other parameters for calculation of head and efficiency. Results showed that the simulated and measured head and efficiency had relative error less than 4%, indicating the feasibility of the simulation method for flow field simulation of guide cones. Simulation on flow velocity of guide cones suggested three flow processes: 1) flow velocity is even in inlet passage and slightly increased; 2) the flow velocity starts to increase and change its direction in contraction passage of guide cone flow field; and 3) the flow field contraction becomes slow in the outlet passage of guide cone. Hydraulic loss of different guide cones varied. The head loss of circular cone was lower than the others. In the sharp contraction cross section of guide cone passage, the uniformity of axial velocity distribution was low, but the velocity weighted average drift angle and radial velocity gradient was high. The rectification capability was better when the contraction at outlet section of guide cone flow field was slow and gentle. Taking into account of uniformity of axial velocity, velocity weighted average drift angle, and the others, the guide cone based on Witozinsky curve had the best rectification capacity and better flow field uniformity. When the length of guide cone was 0.25-0.8 times as impeller diameter, increasing cone length could decrease the hydraulic loss and velocity weighted average drift angle, and improve flow field quality of cone. The results above in combination with practical application, we suggested that the optimal length of the guide cone was 0.5-0.6 times as impeller diameter. This study is helpful to design hydraulic models of high-efficient axial-flow pumps.