CAJ | 학술논문

叶轮偏心将会引起轴流泵叶轮顶部间隙沿周向不均匀，从而导致附加的流动激励和噪声．利用计算流体力学商业软件 Fluent 模拟不同偏心度和间隙比的轴流泵非定常流场，研究周向非均匀间隙对泵内压强脉动及叶轮激励力的影响．结果表明：壁面压强脉动强度并不是在最小间隙处达到最大，而是出现在偏离最小间隙处约30°～60°的方向，并随着间隙比增大，脉动强度最大值发生位置逐渐向最小间隙处靠拢；同时，偏心造成的非均匀叶顶间隙引起了轴频处的压强脉动，在间隙比为2．5％下偏心度从0％增加到60％，轴频处的压强脉动相对增量为661．54％；叶轮受到的径向激励力时均值与偏心度呈线性关系，其斜率与间隙比的平方根成正比．
협륜편심장회인기축류빙협륜정부간극연주향불균균，종이도치부가적류동격려화조성．이용계산류체역학상업연건 Fluent 모의불동편심도화간극비적축류빙비정상류장，연구주향비균균간극대빙내압강맥동급협륜격려력적영향．결과표명：벽면압강맥동강도병불시재최소간극처체도최대，이시출현재편리최소간극처약30°～60°적방향，병수착간극비증대，맥동강도최대치발생위치축점향최소간극처고롱；동시，편심조성적비균균협정간극인기료축빈처적압강맥동，재간극비위2．5％하편심도종0％증가도60％，축빈처적압강맥동상대증량위661．54％；협륜수도적경향격려력시균치여편심도정선성관계，기사솔여간극비적평방근성정비．
Nonuniform tip clearance in axial flow pumps may cause mechanical vibration of the pump and generate larger hydrodynamic noise.The computational fluid dynamic(CFD) software of Fluent is employed to simulate the unsteady flows of the pumps with different relative eccentricities and clearance ratios.Then the influence of nonuniform clearance along circumference on the pressure fluctuation and excitation force is studied.The results show that the maximum pressure fluctuation does not appear at the minimum clearance,but appears at the position where the offset is between 30 degrees and 60 degrees.At the same time,the pressure fluctuation at the shaft frequency is caused by the nonuniform tip clearance.And it increases by 661.54% as the relative eccentricity varies from 0% to 60%with clearance ratio of 2.5%.When the clearance ratio increases,the occurrence of maximum fluctuation intensity transforms to the position of the minimum clearance slowly. Meanwhile,the simulation results also show that there is linear relationship between the time-average excitation force of the impeller and the eccentricity.And the slope is proportional to the square root of clearance ratio.