全喉与半喉模型声门区内准稳态流场分布研究

QUASI-STEADY FLUID FIELD DISTRIBUTIONS IN STATIC LARYNX AND HEMILARYNX MODEL

对于非对称声带发声过程的研究,有助于将正常语音的研究拓展到病理状态,从而为嗓音康复工程打下基础。采用具有嵌入式可活动声门结构的喉部物理模型,研究了声门最小直径为0.0402cm,跨声门压分别为100、500、1000和1500Pa时,全喉及半喉内的准稳态流场分布及其与发声参量的关系。同时,运用三维有限元方法预测了上述边界条件对应的流场分布,计算结果有效地支持了实验数据。结果表明,对称结构下存在着非对称压力和速度成分,但是由于它所占的比率有限(不超过10%),对正常发声的影响不大。非对称结构下,由声门入口处极高的上下表面压力差(通常为跨声门压的1.3倍)导致的倾斜流和涡流的出现、气流分离点位置后移、分离区域增大、声门出入口间压差占跨声门压的比率降低(平均30%)、压力速度场的变化程度减弱等因素以及由此带来的能量损耗,是非对称结构下发声效率降低、发音失真的主要原因。研究提示:声门重建方案的设计应尽量满足对称结构原则。

The research on p honation of asymmetric vocal fold will help to expend the study from normal voice to pathology, which will form the basis of voice rehabi litation. A physical model with embedded and movable glottal structure was used to study the distribution of quasi-steady fluid fields and their relationship with vocal phonation parameter for the transglottal pressure of 100,500,1000 and 1500 Pa in larynx and hemilarynx respecti vely. The minimal glottal diameter was held constant at 0.0402 cm. Thr ee-dimensional finite element method was also adopted to simulate the fluid field distributions under the conditions shown above, the experim ent data were supported well by computational results. Results show th at there are components of asymmetric pressure and velocity in symmetr ic structure, but this portion affect normal phonation little due to its limited ratio (less than 10%). For the asymmetric structure, the ma in reason of reduction in vocal efficiency is the facts caused by ve ry high asymmetric pressure at the entrance of glottal (1.3 times of transglottal), such as emergence of oblique fluid and vortex, lag of their separation point locations, enlargement of separate domain, diminu tion of proportion of transglottal pressures between glottal inlet and outlet in transglottal pressure (average in 30%), weakening of change degree of fluid field, and the wastage of energy caused by them. Th e research suggests that the project of the voice rehabilitation must try to satisfy the principle of symmetric construction.