油菜抗倒伏测试风洞关键部件仿真与试验

为解决现有油菜抗倒伏品种选育周期长、难度大等问题,依托计算流体力学软件Fluent建立油菜抗倒伏测试风洞模型,对风洞扩散段、稳定段、收缩段等关键部位进行参数设计及仿真试验,分析该模型对风洞流场品质的影响,最终通过正交试验选择最佳设计方案。结果显示,单因素试验中,收缩段长度Lc增加,风洞出口风速变异系数增加,气流品质下降;随稳定段长度Lw增加,风洞出口风速变异系数先减小后增加,稳定段长度1 000 mm时,风速变异系数最低,气流品质最佳;阻尼网距稳定段出口长度增加,风洞出口风速变异系数先降低后增加,阻尼网距稳定段出口0.65Lw时,风速变异系数最小。正交试验结果显示,收缩段长度600 mm、稳定段800 mm、阻尼网距风洞出口0.65Lw时,对应风洞试验区风速平均变异系数为0.139,风速较其他方案更稳定,气流品质最佳。实测验证发现,与仿真结果相比,实测风速大小无明显差别,且实测结果中各截面风速变异系数略优于仿真值,整体仿真结果与实测效果拟合较好。

Simulation and testing of key components of wind tunnel for rapeseed lodging resistance testing

Wind tunnel devices play an important role in studying the lodging resistance of rapeseed in strong wind environments. The wind tunnel model of rapeseed lodging resistance test was established based on computational fluid dynamics software Fluent. The design of parameter and simulation tests on key parts of the wind tunnel including diffusion section, stabilization section and contraction section were conducted. The effects of key parts of the wind tunnel on the quality of the wind tunnel flow field were analyzed. The optimal design scheme was selected with orthogonal experiments. The results showed that the variation coefficient of wind velocity at the outlet of the wind tunnel increased when the length of the shrinkage section Ls increased, and the quality of airflow decreased in the single factor experiment. As the length of the stable section Lw increased, the coefficient of variation of wind tunnel outlet wind speed first decreased and then increased. When Lw was 1 000 mm, the coefficient of wind speed variation was the lowest and the airflow quality was the best. The wind speed variation coefficient of wind tunnel outlet first decreased and then increased with the increase of the outlet length of the stabilization section of the damping net distance. When the damping net was 0.65Lw away from the wind tunnel outlet, the variation coefficient of wind speed was the smallest. Among the 9 orthogonal experimental schemes, when the shrinkage section length was 600 mm, the stabilization section was 800 mm, and the damping net was 0.65Lw away from the wind tunnel outlet, the average variation coefficient of wind speed in the corresponding wind tunnel test area was 0.139. The wind speed was more stable than other schemes, and the airflow quality was the best. It is indicated that there is no significant difference between the measured wind speed and the simulation value in scheme 2 wind tunnel. It will provide data support and proof for the design of wind tunnel.