基于等 Weber 数的结冰外形修正

由于设备条件的限制,在进行结冰风洞试验时,试验 Weber 数与目标 Weber 数往往存在差异,为了获得与目标 Weber 数对应的冰形,需要对试验结果进行修正。本文分析了进行 Weber 数修正的原因,提出了根据几何特征量进行结冰外形修正的方法,并以某超临界翼型为对象,对不同 Weber 条件下的结冰外形进行了仿真,研究了Weber 数变化对结冰的影响规律,在此基础上开展了基于等 Weber 数的结冰外形修正。研究发现：(1)Weber 数主要影响冰角特征,对水滴收集特性、结冰极限及驻点冰厚度影响较小；(2)存在一个敏感 Weber 数,低于敏感值时, Weber 数变化对结冰影响不大,当 Weber 数高于敏感值时,Weber 数变化对结冰有明显影响；(3)采用本文提出的冰形修正方法,能保证冰形的宏观轮廓与目标冰形一致,修正后的冰形能适量消除由于 Weber 数误差导致的冰形差异,提高试验的精度。

Ice shape modification based on constant Weber number

The Weber number in an icing wind tunnel test is often different from that of the real flight icing condition due to the limitation of facility capacity.In order to obtain consistent result of aimed Weber number,the test ice shape need to be modified.The reason of icing test data correction is analyzed in this paper.A method for ice shape modification based on the ice geometric features is proposed.The ice shape of a supercritical airfoil is simulated under the condition of different Weber number,and the effect of Weber number on icing is studied.Then the ice shape modification based on constant Weber number is carried out.It is found that:(1) The Weber number mainly affects ice horns,and has little influence on droplet collection,icing limit and thickness;(2)There is a sensitive value existed,as the Weber number changes smaller than the value ice varies little,while the Weber number is bigger than the value,ice will vary obviously according to the change of this Weber number;(3 )The proposed ice modification method can guarantee the agreement between the modified and the target ice shape,so the ice shape differences caused by Weber number differences can be amount to eliminated,and the precision of test will be improved.