某燃气轮机整机试验过程中,压气机部分存在高压压气机效率偏低的问题,且高、低压压比分配与设计情况存在偏差。经分析,低压压气机与高压压气机径向落差大,导致中间的过渡段内损失较大,进一步导致高压压气机进口流场品质较差,可能是高压压气机效率较低的主要原因。针对该情况,将过渡段内、外壁型线参数化,用两段四次曲线表示,在大范围内寻优,同时优化支板结构,进一步降低气流流动分离,最终确定优化方案。经流场分析发现,过渡段内壁面逆压力梯度流动会影响壁面边界层的发展,导致局部流动分离,引起较强的径向掺混,是过渡段内损失产生的主要原因,优化方案通过将逆压流动位置前移的设计,进行流动控制,降低总压损失。为验证方案的有效性,单独针对改进方案进行了吹风试验,结果表示,优化后过渡段内的流动总压损失降低至原来的18%,优化方案极大的改善了过渡段内的流动分离情况。

During the testing process of a marine gas turbine, high-pressure compressor has low efficiency, and there was a deviation between the distribution of pressure ration assignment and the design situation. After analysis, the large radial drop between the low-pressure compressor and high-pressure leads to significant losses in the intermediate transition section, further leading to poor quality of the inlet flow field of the high-pressure, which may be the main reason for the low efficiency of the high-pressure compressor. In view to this situation, the inner and outer wall profiles of the transition section are parameterized and represented by two quartic curves to seek optimization over a large range. At the same time, the support plate structure is optimized to further reduce airflow separation, and the optimization plan is ultimately determined. Through flow field analysis, it is found that the adverse pressure gradient flow on the inner wall of the transition section will affect the development of the wall boundary layer, leading to local flow separation and strong radial mixing, which is the main reason for the loss in the transition section. The optimization scheme controls the flow by moving the adverse pressure gradient flow position forward to reduce the total pressure loss. To verify the effectiveness of the scheme. Wind tunnel blowing tests were conducted on the optimization scheme. The results showed that the total pressure loss in the transition section was reduced to 18% after optimization, greatly improving the flow separation situation in the transition section.

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