圆盘通风制曲设备气流组织均匀性优化

Optimization of Air Distribution Uniformity of Disc-ventilated Koji Making Equipment

针对南方某酱油制造厂圆盘通风制曲设备内气流组织不均匀问题,采取测试、数值模拟方法对气流组织优化措施进行探讨。改造前测试结果:下风室的最大风速与最小风速相差较大,不均匀系数接近甚至超过1,说明下风室的气流组织明显不均匀。上风室的最大风速与最小风速相差较小,不均匀系数也比较小,仍存在一定的不均匀性。改造前模拟结果:下风室内气流组织明显不均匀。在0.9 m测试截面上,空气在进风口后形成了明显的高速区,并延伸至风室壁面,导致风室内壁面的风速比较高。在2.5 m测试截面上,受进风影响,进风口后高速区上部出现了最大流速,远离进风口一侧的风室内壁面风速比较高。改造措施:措施1:加宽排风口。措施2:加大下风室中心柱直径。措施3:进风口增加导流板。措施4:在进风口增加导流板的基础上,加大下风室中心柱直径。措施5:进风口增设多孔板罩。与改造前相比,措施1~3对改善气流组织均匀性的作用并不明显,进风口后仍存在明显高速区,并延伸至风室壁面,导致风室内壁面附近的风速比较高。虽然措施4的进风口后仍存在明显高速流,但延伸长度缩短,风室内壁面附近的高速区也得到有效缓解。与改造前及措施1~4相比,采取措施5后,进风口后未出现明显的高速区,测试截面的气流组织均匀性得到明显改善。在5种措施中,措施5对2.5 m测试截面气流组织的改善效果最明显。措施5对圆盘通风制曲设备气流组织的改善效果最优。在研究的孔板开孔率中(55%、35%、18%),最佳开孔率为35%。改造后测试结果:与改造前相比,各测试截面上的风速分布更加均匀。各测试截面的不均匀系数均出现了下降,说明措施5对改善圆盘通风制曲设备内气流组织不均匀问题有效。

Aiming at the problem of uneven air distribution in the disc-ventilated koji making equipment of a soy sauce factory in the South,the testing and numerical simulation methods are adopted to discuss the air distribution optimization measures. Test results before transformation: The maximum wind speed of the lower air chamber is different from the minimum wind speed,and the unevenness coefficient is close to or even more than 1,indicating that the air distribution in the lower air chamber is obviously uneven. The difference between the maximum wind speed and the minimum wind speed of the upper air chamber is small,the unevenness coefficient is also relatively small,and there is still a certain degree of unevenness. The simulation results before the transformation: the air distribution in the lower air chamber is obviously uneven. On the test section of 0. 9 m,the air forms an obvious high-speed zone behind the air inlet and extends to the wall of the wind chamber,resulting in a relatively high wind speed on the inner wall of the wind chamber. On the test section of 2. 5 m,affected by the air intake,the maximum flow velocity appears in the upper part of the highspeed zone behind the air inlet,and the wind speed on the inner wall of the wind chamber away from the air inlet is relatively high. The transformation measures:Measure 1: widening the air outlet. Measure 2: increasing the diameter of the center column of the lower air chamber. Measure 3: adding deflector at the air inlet. Measure 4: on the basis of adding deflector at the air inlet,increasing the diameter of the center column of the lower air chamber. Measure 5: adding perforated plate cover to the air inlet. Compared with before the transformation,the effect of the measures 1 to 3 on improving the uniformity of air distribution is not obvious. There is still an obvious high-speed zone behind the air inlet,and it extends to the wall of the wind chamber,resulting in higher wind speed near the wall of the wind chamber. Although there is still an obvious high-speed flow behind the air inlet of the measure 4,the extension length is shortened,and the high-speed zone near the wall of the wind chamber is also effectively relieved. Compared with before the transformation and the measures 1 to 4,after taking the measure 5,there is no obvious high-speed zone behind the air inlet,and the uniformity of the air distribution of the test section is significantly improved. Among the five measures,the measure 5 has the most obvious improvement effect on the air distribution of the test section of 2. 5 m. The measure 5 has the best improvement effect on the air distribution of the disc-ventilated koji making equipment. Among the aperture ratios of the studied orifice plates( 55%,35% and 18%),the best aperture ratio is 35%. The test results after transformation:compared with before transformation,the wind speed distribution on each test section is more even. The unevenness coefficient of each test section is decreased,indicating that the measure 5 is effective to improve the uneven air distribution in the disc-ventilated koji making equipment.