| 摘要: | 本研究採用儲槽循環卸載實驗探討顆粒體在不同開口尺寸的七種置入物儲槽中的流動行為，此七種置入物分別為無置入物、倒圓錐型、圓片型、圓柱型、球型、圓錐中空型與圓柱中空型，提出擬三維儲槽循環卸載實驗模擬顆粒體在實際三維儲槽中的流動行為，並進一步分析置入物對儲槽中顆粒流傳輸性質的影響，實驗用顆粒為球形白色ABS 樹脂顆粒體，同時採用 PIV 與 PTV 方法量測顆粒體的速度分佈，並比較兩者量測結果，研究結果顯示：(1)整體上 PIV 與 PTV 兩種量測方法求得的速度分析結果趨近一致，然而兩者計算方法的不同，在儲槽出口處以及邊壁處有較大的誤差，仍需進一步探討。(2)15cm 開口尺寸與 10cm 開口尺寸儲槽中，兩種影像量測技術皆顯示倒圓錐型、圓片型、圓柱型與球型置入物呈現較為均勻的垂直速度分佈，圓柱中空型置入物儲槽中
置入物內側顆粒體的垂直速度較外側快很多，呈現極不均勻的垂直速度分佈。(3)與無置入物儲槽相比，15cm 開口尺寸儲槽中，倒圓錐型、圓片型、圓柱型與球型置入物使儲槽整體呈現較小的粒子溫度分佈，有較大區域的均勻流場，而 10cm 開口尺寸儲槽中，倒圓錐與圓片型使儲槽整體呈現較小的粒子溫度分佈。(4)15cm 開口尺寸儲槽中，無置入物型、倒圓錐型、圓片型、圓柱型、球型與圓錐中空型置入物儲槽的垂直擾動速度分佈皆近似於馬克斯威爾分佈，擾動速度較小，圓柱中空型置入物儲槽的垂直擾動速度分佈較為寬廣呈現 M 型分佈，代表其垂直速度極為不均變化較大，10cm 開口尺寸儲槽中，倒圓錐型置入物的垂直擾動速度近似馬克斯威爾分佈，圓片型、圓柱型、球型與圓錐中空型置入物儲槽的垂直擾動速度分佈則向右偏移，圓柱中空型置入物儲槽的垂直擾動速度分佈仍然較為寬廣，分佈較為不均。;The purpose of this study is to investigate the flow behavior of granular materials in cylindrical silos with different opening sizes and seven different inserts by experiment. The orifice size of silos were 10cm and 15cm respectively. These inserts include conical insert, disk insert, solid cylinder insert, sphere insert, BINSERT and hollow cylinder insert. Quasi-three-dimensional silo is proposed to mimc the flow behavior of granular materials in the three-dimensional silo. Both Particle Image Velocimetry (PIV) and Particle Tracking Velocimetry (PTV) methods were used to measure the velocity fields for the granular flow, and the corresponding results were compared and discussed. Furthermore, the effect of insert geometry on transport properties of the granular flow in the silo is analyzed. Key findings are highlighted below: (1) Generally, the velocity profiles for the granular flow obtained by the PIV and PTV measurement methods are quite consistent. However, there are some discrepancies at the exit and the side wall of silos, which needs to be further investigated; (2) For the silos with the conical insert, disk insert, solid cylinder insert and sphere insert, both measurement techniques show that the granular flow exhibits uniform vertical velocity profiles. However for the silo with the hollow cylinder insert, the granular vertical velocity inside the insert is much faster than that outside the insert, exhibiting an extremely uneven vertical velocity profile; (3) Compared with silos with no insert, 15cm-orifice silos with conical insert, disk insert, solid cylinder insert and sphere insert exhibit small and more evenly distributed granular temperature. Similarly, 10cm-orifice silos with conical insert and disk insert also show small and more evenly distributed granular temperature; (4) In the 15cm-orifice silos with no insert, conical insert, disk insert, solid cylinder insert, sphere insert and BINSERT, the distribution of fluctuation velocity is uniform and similar to the Maxwell distribution. By contrast, for the silo with hollow cylinder insert, the fluctuation velocity is widely distributed and exhibits an M-shaped distribution, indicating that the vertical velocity is not uniform; and (5) In the 10cm-orifice silo with conical insert, the fluctuation velocity shows the Maxwell distribution. However, for the silos with disk insert, solid cylinder insert, sphere insert and BINSERT, the distribution of fluctuation velocity is shifted to the right. For the silo with hollow cylinder insert, the fluctuation velocity is still distributed widely and unevenly. |
