针对当前多声道时差式超声流量计空间对称式声道结构声道覆盖率较低，对不 规则流场适应力较弱等问题，提出了立体多声道模型设计理论． 推导出了满足期望覆盖率 下的最少声道段数、各声道段与管道中心距离、声道数目及平面模型组合排列数量、单一 声道的平面模型相邻声道段夹角的计算公式; 进行了多声道拓扑结构设计; 最后进行了算 例设计和样机生产． 实例计算与应用表明，文中提出的时差式超声流量计立体多声道模型 设计方法具有可行性、先进性和实用性的特点．

Focusing on the problems such as low track coverage and weak adaptability to the irregular flow field in the current symmetrical track model of transit-time ultrasonic flow-meter，the design theory of 3D multi-path model is explored． Firstly，the formula for calculating the minimum number of paths satisfying the expected coverage is deduced． The distance between each path and the center of the pipeline is solved． The number of paths and the number of 2D track model are calculated． The angle between adjacent path segments of a 2D track model of a single path is calculated． Then，the coordinates of multi-path topology node are solved． Finally，multi-path topology is designed． The example calculation and application show that the design method of transit-time ultrasonic flow-meter 3D multi-path model is feasible，advanced and practicable．