基于CFD的棉纤维长度检测装置吸风口结构优化与试验

Optimization and Experiment of Suction Inlet Structure of Cotton Fiber Length Detection Device Based on CFD

摘要:

棉纤维长度是棉花品质检测的关键指标之一。为保证棉纤维检测时处于稳定伸直状态，结合计算流体力学（CFD）和正交试验对自主设计的棉纤维吸风口内部气流场进行数值模拟和优化。通过单因素试验分析吸风口长度、宽度和高度对腔体流场均匀性、气流速度及压力的影响，并通过数值模拟与正交试验优化吸风口参数配置。单因素结果试验表明，较优参数高度为2.6~3.0 mm，宽度为40~60 mm，长度为65~105 mm。确定速度不均匀系数和压力不均匀系数综合加权得分作为评价指标，通过正交优化试验研究影响吸风口内部气流场分布的因素，结果表明，影响气流场均匀性主要因素依次为吸风口长度、高度和宽度。优化后吸风口结构参数组合为：高度2.8 mm、宽度50 mm、长度85 mm。在此组合下，截线A、B、C速度不均匀系数相对于9种试验平均值分别下降0.30、0.33和0.31，压力不均匀系数下降0.13、0.21和0.21，速度和压力综合加权得分最高达到99.979 3和99.688 9。通过对35组棉样图像逐行像素数量对比验证，最优参数组合在3组行区间（每个图像按行划分3组）的占比分别为86.44%、46.77%和10.61%，表现出最佳棉纤维伸直度，且与数值模拟结果一致。研究结果为棉纤维吸风口气流分布评价方法提供参考以及棉纤维长度精准检测奠定了基础。

Abstract:

Cotton fiber length is one of the key indicators in cotton quality testing. To ensure that cotton fibers remain stable and straight during testing, the airflow field inside a self-designed cotton fiber suction port was numerically simulated and optimized using computational fluid dynamics (CFD) and orthogonal experiments. Single-factor experiments were conducted to study the effects of suction port length, width, and height on the uniformity of the flow field, airflow velocity, and pressure within the cavity. The suction port parameters were optimized through numerical simulation and orthogonal experiments. Single-factor test results indicated that the optimal range for height was 2.6~3.0 mm, width was 40~60 mm, and length was 65~105 mm. Through orthogonal optimization experiments, using the weighted score of velocity and pressure non-uniformity coefficients as evaluation criteria, the factors affecting the airflow field distribution inside the suction port were analyzed. The results showed that the main factors affecting flow field uniformity in order were the length, height and width of the suction port. The optimized suction port structural parameters were as follows: height was 2.8 mm, width was 50 mm, and length was 85 mm. Under this configuration, the velocity non-uniformity coefficients at sections A, B, and C were decreased by 0.30, 0.33 and 0.31 compared with the average test values, and the pressure non-uniformity coefficients were decreased by 0.13, 0.21 and 0.21, respectively. The comprehensive weighted scores for velocity and pressure reached a maximum of 99.979 3 and 99.688 9, respectively. Verification through comparison of pixel counts in 35 groups of cotton sample images by row showed that the optimal parameter configuration had coverage rates of 86.44%, 46.77% and 10.61% in three row intervals (each image divided into three groups by rows), demonstrating the best fiber straightness, which was consistent with the numerical simulation results. The research result can provide a reference for evaluating the airflow distribution in cotton fiber suction ports and lay a foundation for accurate cotton fiber length detection.