振荡水柱波能装置冲击式空气透平优化数值模拟研究

Numerical Study on Optimization of Impulse Air Turbines for OWC Wave Energy Conversion

冲击式空气透平是振荡水柱式波能发电装置的二级能量转换装置,具有自启动性能好、在大流量系数区保持较高效率等优势,近年来应用越来越广泛。有学者提出在冲击式透平动叶片尖端安装环结构的设计,可以改善动叶片叶尖间隙处的气流流动形态,提高透平的工作性能。依托于此观点,构建了安装有环结构的冲击式透平的三维定常数值模型,并通过网格数量无关性及试验数据,验证了该数值模型的准确性与可靠性,随后开展了一系列仿真计算。此外,研究了不同环结构厚度对冲击式空气透平输入系数、扭矩系数及透平效率的影响规律,确定最优结构参数,该优化结果可为实际工程应用中冲击式空气透平的结构选型提供可靠依据。后续将对端板、嵌槽等其他尖端结构展开研究,实现冲击式透平的进一步优化。

Impulse air turbine is a secondary energy conversion device of the oscillating water column(OWC)wave energy converter.It has the advantages of good self-starting performance and high efficiency in the areas with large flow coefficient and has been applied more and more widely in recent years.Some scholars have proposed that the design of installing ring structure at the tip of the rotor blade of the impulse turbine can ameliorate the air flow pattern at the tip clearance of the rotor blade and improve the performance of the turbine.Based on this point of view,a three-dimensional constant numerical model of the impulse turbine with ring structure installed is established and its accuracy and reliability have been verified by grid quantity independence and experimental data.A series of simulation calculations are then carried out.In addition,the influences of the thickness of different ring structures on the input coefficient,torque coefficient and turbine efficiency of the impulse air turbine are studied and the optimal structural parameters are determined.The optimization results can provide a reliable basis for the structure-type selection of impulse air turbines in practical applications.In the future,other tip structures such as the end plates,the bezels,and so on will be studied in order to realize the further optimization of impulse turbines.