高压涡轮主动间隙控制系统机匣模型试验

设计和搭建了叶尖主动间隙控制系统的核心——可控热变形机匣模型试验验证台，利用机匣温度和变形量等参数的测量，验证了某主动间隙控制设计方案的基本工作特性.试验中通过改变集气腔进气流量，研究了不同试验工况下机匣温度分布规律，获得了机匣径向变形量及其在周向和轴向的分布规律.研究中发现冷却空气管的多孔冲击射流可以有效改变机匣温度，并达到调节机匣变形的最终目的.随着供气雷诺数增加，机匣的热响应时间减小，机匣的收缩速率明显增加，但该增加幅度随着雷诺数的增加而逐步减弱.试验结果表明:机匣径向冷却收缩量基本均匀.由于冷却空气管周向流量分配不均匀，使其周向上最大相对偏差为8.75%.同时冷却空气管结构和供气量差异会导致机匣轴向温度分布不均匀，在该验工况中，机匣径向冷却收缩量在轴向上最大的相对偏差为6.99%. 

Experiment on active clearance control system of high pressure turbine case with thermal deformation control

An experimental rig was established to get the performance of high pressure turbine case with thermal deformation control, serving as one of the most important parts of active clearance control (ACC) system. The distribution of temperature and radial deformation was measured to show how the turbine case responded to the temperature variation. In experiments, the coolant mass flow rate of inlet was changed, then the information of temperature and radial deformation was recorded. The rules of those parameters varying in axial and circumferential directions were also studied. It was found in experiments that the temperature of case could be controlled with impingements formed by the staggered jet holes in cooling pipes, which were placed outside the case. Therefore the thermal deformations were also controlled due to those jet impingements. With the increase of coolant mass flow, the response time of thermal deformation decreased significantly at first and then tended to be a certain value. The experimental results showed that the radial thermal deformation of case was substantially uniform. But uneven circumferential distribution of coolant jetting from the pipes can still lead to some non-uniformity of radial thermal deformation in circumferential direction. The maximum relative deviation was about 8.75%. At the same time, the case''s temperature in axial direction was also affected by the coolant flow and structural parameters. The maximum relative difference of radial deformation in axial direction as 6.99% was observed in experiments.