重型燃气轮机透平第一级动叶复合冷却数值研究

Numerical Investigation on Compound Cooling Effect of the Heavy-duty Gas Turbine First Stage Blade

以某重型燃气轮机透平第一级动叶为研究对象,考虑动叶进口参数沿径向不均匀性、工质变物性、冷气掺混带来燃气组分变化等因素,基于非结构混合网格,在额定工况下采用流热耦合方法对其气动传热特性进行数值研究,分析复合冷却效果,与实际运行叶片烧蚀情况进行对比,并分析复杂流场对换热效果的影响。结果表明:数值计算与实际叶片运行结果相吻合;采用流热耦合方法可以准确预测透平叶片烧蚀情况;50%和90%叶高截面冷却效率自前缘至尾缘具有相似的前高后低分布,10%叶高截面冷却效率前低后高;通道涡、叶顶间隙泄漏涡等复杂的二次流漩涡将会对流道温度场分布产生很大的影响。

The conjugate heat transfer（CHT） method was employed on the first stage blade of a heavy-duty gas turbine to study its aerodynamic and heat transfer characteristics under the rated conditions, as well as its composite cooling effect. Some influencing factors, such as nonuniformity of inlet condition radial distribution, the variable properties of the working fluid and component variation of gas caused by the mixing of coolant was considered in the simulation process based on unstructured mesh. Then numerical simulation results were compared with the ablation of failed blade. The effects of complex flow field to heat transfer were analyzed. The results indicate that numerical simulations agree well with the actual running results. The conjugate heat transfer（CHT） method can accurately predict the ablation of turbine blade. At both 50% and 90% spans, the cooling efficiency is high at leading edge and low at trailing edge, while an inverse distribution appears at 10% span. Complicated secondary flow vortices such as passage vortex and tip leakage vortex have a significant impact on the temperature distribution in flow channel.