不同流动配置下涡轮叶片交错肋冷却流动传热特性数值模拟

Numerical Simulations for Flow and Heat Transfer Characteristics in Different Latticework Cooling Configurations for Gas Turbine Blades

关键词:  涡轮叶片  交错肋冷却配置  传热  流动配置  数值模拟

Key words:  Turbine blade  Latticework cooling configuration  Heat transfer  Flow configuration  Numerical simulation

摘要:

为掌握交错肋冷却结构应用在涡轮叶片不同区域的流动传热性能，针对一种交错肋冷却结构在三种不同流动配置中在等质量流量和子通道雷诺数工况下进行了数值计算研究。三种流动配置包含了径向流动配置（RFC），横向流动配置（CFC）和转折流动配置（TFC）。通过比较本研究得到的数值模拟结果与公开文献中的实验数据，定性定量地验证了数值计算的有效性。在等冷却质量流量下，RFC配置拥有最高的平均努塞尔数和压力损失，而CFC和TFC配置的平均传热性能相似且明显降低，但压力损失大大减少。在相同的子通道雷诺数下，三种流动配置下的交错肋通道展现出相似的传热强化性能，但TFC配置的压力损失最小。在研究范围内，在RFC配置中肋表面的平均换热比主表面的平均换热约高出16.3%，而在CFC配置和TFC配置中该值则分别高出38.2%以及 30.6%。不同的流动配置会引发子通道内不同的流动特性，包括流动转折和子通道间的交互作用。

Abstract:

To get knowledge of the flow and heat transfer performance of latticework structure used in different sections in gas turbine blades， a numerical study has been carried out in different latticework cooling configurations under the same mass flow rates and under the same subchannel Reynolds numbers. The three latticework cooling configurations are the radial flow configuration （RFC）， the cross flow configuration （CFC） and the turning flow configuration （TFC）. The comparisons between the present numerical data and the experimental data validated the numerical approach both qualitatively and quantitatively. Under the same cooling mass flow rates， the RFC latticework obtains the highest averaged Nusselt numbers and the largest pressure losses， and the CFC and TFC latticework obtain appreciably lower but similar averaged heat transfer performance with much reduced pressure loss. Under the same subchannel Reynolds numbers， the three latticework cooling configurations show similar averaged heat transfer enhancement， but the pressure loss for the TFC latticework is the smallest. In present study， the average heat transfer coefficient at fin surfaces is 16.3% higher than that at primary surfaces in RFC latticework， and the corresponding value for CFC and TFC latticework are 38.2% and 30.6% higher. Different latticework cooling configurations produce different flow characteristics including the flow turnings and interactions among the subchannels.