低层双齿大棚屋面风致积雪分布研究

为研究低层双齿大棚屋面的风致积雪分布规律,基于FLUENT软件中的Mixture多相流模型,建立了风雪两相流场模型。为验证风雪两相流场的准确性并选择合适的湍流模型,采用k-w,SST k-w和k-kl-w湍流模型分别对立方体周围积雪分布进行数值分析,并将数值分析结果与试验结果进行对比以验证数值方法的正确性,进而详细研究了风速、风向角、屋面坡度比和结构双齿长宽比对低层双齿大棚屋面风致积雪分布的影响。结果表明:风雪两相流模型和k-kl-w湍流模型建立的风雪两相流流场可以较好地反映低层双齿大棚屋面的积雪分布情况; 大棚屋面积雪厚度随着风速和屋面坡度比增大而减小,且屋面坡度比的影响程度较风速与风向角的影响小; 大棚屋面积雪受侵蚀和堆积区域位置随风向角变化而变化; 大棚结构长宽比对屋面积雪分布的影响较小; 低层三齿大棚屋面和低层四齿大棚屋面的屋面积雪分布系数可参考低层双齿大棚屋面; 提出的低层双齿大棚屋面积雪不均匀分布系数可为低层双齿大棚屋面的冬季防雪灾设计提供参考。

Investigation on Roof Wind-induced Snow Distribution of Low-rise Double-tooth Greenhouses

In order to study the wind-induced snow cover on the roof of low-rise double-tooth greenhouse, based on the Fluent, the Mixture multiphase flow model was selected, the wind and snow two-phase flow models were established. To verify the accuracy of the wind and snow two-phase flow field and choose the reasonable turbulence model, the k-w, SST k-w and k-kl-w turbulence models were used to simulate the snow distribution around the cube. Then, the numerical results were compared with the test results to verify the correctness of the numerical models. The influences of wind speed, the wind direction, the roof slope ratio, and the length-span ratio on the distribution of wind-reduced snow cover on the roof of low-rise double-tooth greenhouses were studied in detail. The results show that the distribution of wind-reduced snow cover on the roof of the low-rise double-toothed greenhouse can well reflected through the wind and snow two-phase flow model and two-phase flow field established using k-kl-w turbulence model; the snow thickness on the roof of the greenhouse decreases with the increase of the wind speed and the roof slope ratio, however, the influence degree of roof slope ratio is smaller than that of wind speed and wind direction; the snow erosion and accumulation position on the roof of the greenhouse changes with the wind direction; the length-span ratio of the greenhouse structure has little effect on the distribution of snow on the roof. The snow distribution coefficient of the low-rise three-tooth greenhouse roof and the low-rise four-tooth greenhouse roof can refer to the low-rise double-tooth greenhouse roof; the proposed uneven distribution coefficients of snow on the roof of low-rise double-tooth greenhouses can provide a reference for winter snow disaster prevention design of the low-rise double-tooth greenhouses roof.