Abstract: Secondary flow is a common physical phenomenon in engineering practice, which is a secondary flow relative to the mainstream. In order to study the influence of secondary flow on airflow velocity and different particle sizes of sand particles in a sand sampler, this paper uses a combination of numerical simulation and experimental verification to analyze the flow field characteristics before and after secondary flow is weakened, taking the windsand separator of the shunthedging and multistage expansion sand sampler as the research object. The research results indicate that before secondary flow is weakened, sand with a particle size greater than 0.083 mm are completely collected, while sand with a particle size less than 0.083 mm are mostly collected. After secondary flow is weakened, the distribution range of highspeed airflow becomes larger, and the flow field seems to become unstable. The airflow velocity inside the exhaust pipe significantly increases, and only sand with a particle size greater than 0.12 mm are completely collected, and the range of sand being completely collected is significantly reduced.

Key words: sand sampler, secondary flow, numerical simulation, the windsand separator

摘要： 二次流动是工程实际中普遍存在的物理现象，是一种相对于主流的次要流动。为研究集沙仪内二次流对气流速度、不同粒径的沙尘粒子的影响规律，利用数值模拟和试验验证相结合的方法，以分流对冲与多级扩容式集沙仪的风沙分离器为研究对象，对二次流被削弱前后的流场特性进行分析。研究结果表明：在二次流被削弱前，粒径大于0.083mm的沙尘被完全收集，粒径小于0.083 mm的沙尘被大部分收集；在二次流被削弱后，高速气流分布范围更大，流场似乎变得不稳定，排气管内气流速度明显增高，粒径大于0.12 mm的沙尘才被完全收集，沙尘被完全收集的范围明显缩小。

关键词: 集沙仪, 二次流, 数值模拟, 风沙分离器