CAJ | 학술논문

液力偶合器内部流动特性对能量的高效传递非常重要。深入研究液力偶合器内部流动机理和流场结构分布，对于优化液力偶合器腔型结构并进一步提高其工作性能具有重要意义。液力偶合器的内部流场是具有多种流动结构和多种物理效应并存的流场，存在多种复杂的流动现象，尤其在制动工况下液力偶合器涡轮内部流动是一种特殊的漩涡流动。为了研究制动工况下涡轮独立流道内漩涡流动的产生与运动，基于粒子图像测速技术（particle image velocimetry，PIV）采集涡轮径向切面流动图像。通过灰度化增强、阈值分割、边缘检测、锐化等图像处理技术识别涡轮内部大尺度漩涡流动，定性分析流场结构分布；采用连续帧图像互相关算法定量提取涡轮内部速度场和涡量场，研究涡轮内部小尺度漩涡流动；分析漩涡流动产生的原因及其对液力偶合器能量传递的影响；讨论不同尺度涡旋发展变化的过程，通过涡量场分布结果研究流体能量耗散。分析涡轮近壁面流动区域上的漩涡流动，证明壁面边界区域上的相对涡量将对能量耗散产生重要影响。通过PIV试验研究实现了涡轮内部漩涡流动可视化与流动参数定量化提取，PIV试验研究结果可为液力偶合器内部流动机理研究提供参考。
액력우합기내부류동특성대능량적고효전체비상중요。심입연구액력우합기내부류동궤리화류장결구분포，대우우화액력우합기강형결구병진일보제고기공작성능구유중요의의。액력우합기적내부류장시구유다충류동결구화다충물리효응병존적류장，존재다충복잡적류동현상，우기재제동공황하액력우합기와륜내부류동시일충특수적선와류동。위료연구제동공황하와륜독립류도내선와류동적산생여운동，기우입자도상측속기술（particle image velocimetry，PIV）채집와륜경향절면류동도상。통과회도화증강、역치분할、변연검측、예화등도상처리기술식별와륜내부대척도선와류동，정성분석류장결구분포；채용련속정도상호상관산법정량제취와륜내부속도장화와량장，연구와륜내부소척도선와류동；분석선와류동산생적원인급기대액력우합기능량전체적영향；토론불동척도와선발전변화적과정，통과와량장분포결과연구류체능량모산。분석와륜근벽면류동구역상적선와류동，증명벽면변계구역상적상대와량장대능량모산산생중요영향。통과PIV시험연구실현료와륜내부선와류동가시화여류동삼수정양화제취，PIV시험연구결과가위액력우합기내부류동궤리연구제공삼고。
It is very important to study internal flow characteristics of hydrodynamic coupling for its high efficient energy transmission. Consequently, it has great significance for us to study the internal flow mechanism and flow distribution of hydrodynamic coupling deeply. Based on this theoretical analysis, the cavity structure of hydrodynamic coupling can be further optimized, and it has great significance to enhance the performance of hydrodynamic coupling. A variety of flow structures and many physical effects will coexist in the internal flow field of hydrodynamic coupling, and there are many complex flow phenomena. Especially on braking condition, internal flow of turbine is a special kind of vortex flow. In order to study the generation and movement of vortex flow in the independent flow channel, flow images of radial cross-section in turbine was captured based on particle image velocimetry (PIV) technology. The large-scale vortices were identified by image processing techniques, including gray enhancement, threshold segmentation, edge detection and image sharpening. Based on this, the direction of flow velocity was identified and extracted clearly. The distributions of flow field were qualitative analyzed. The flow field and vorticity field were extracted through successive frames of image cross-correlation algorithm, and the small-scale vortices were discussed. The reasons of vortices generation and their impacts on energy transmission were analyzed. The development process of different scale vortices was discussed. The energy dissipation of flow was studied through distribution results of vorticity field. On the near-wall flow region of turbine, vortex flow was analyzed. Based on this, relative vorticity on the wall boundary region might have an important impact on the energy dissipation. The flow visualization of vortices and quantitative extraction of flow parameters were achieved by PIV technology and a valuable reference for the internal flow mechanism of hydrodynamic coupling was provided by PIV experimental results.