结冰风洞试验混合相似转换方法及其验证

A hybrid scaling method for icing wind tunnel and validation

  • 摘要: 相似转换是结冰风洞试验的重要技术手段,使用常见的相似转换方法有时会获得风洞能力外的转换结果,为了克服常见转换方法存在的适用范围限制,本文通过对相似参数的影响因素进行分析,获得了试验参数在相似准则约束下的变化规律和关联性。在此基础上提出了一种混和相似转换方法,其转换流程分为由水滴惯性系数和驻点冻结系数控制的两个阶段,根据满足的相似参数不同分为四种模式:模式1可以同时满足所有主要相似参数和三种热平衡参数;模式2和模式3分别为ONERA方法和Ruff方法的改进;模式4直接使用了Olsen方法。通过数值模拟和风洞试验对混合相似转换方法进行了验证,转换冰形与参考冰形基本一致,转换后的试验参数对比其他转换方法更具实用性。

     

    Abstract: The scaling on test condition is an essential technique for icing wind tunnel tests to achieve conditions exceeded the capability of the wind tunnel facility. In order to overcome the shortages of usual scaling methods, a hybrid scaling method is presented. This method analyzes the scaling parameters and correlations of test conditions under constraints of scaling law. The hybrid method is partitioned into a two-stage procedure to coincide the principle scaling parameter, namely the inertia parameter and stagnant freezing factor respectively. And four modes are derived corresponding to different sets of target scaling parameters. The feature of mode 1 is the capability of coinciding all scaling parameters including three heat balance parameters which is not usually meet simultaneously. Mode 2 and mode 3 are considered as improved ONERA method and Ruff method respectively, in which the sequence of solving scaling equations are modified while the target parameters to meet are kept. Mode 4 applied Olsen method in the second stage procedure unchanged. Such method was tested by numerical simulation and wind tunnel tests with satisfying agreement of the resultant ice shape, and therefore the validity and practicality are proven.

     

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