NUMERICAL RESEARCHES ON INTERACTION BETWEEN PROPE- LLERS IN UNIFORM FLOW

Numerical simulations of the flow around two bidirectional staggered propellers are conducted in uniform flow. The computed open water performance of the fore-propeller is compared with the corresponding experimental results, and the influence of the fore-propeller on the aft one is carefully investigated. It is found that the inflow around the aft propeller close to the side of the fore is especially affected by the fore one, leading to abnormal circumferential distribution of force on the blade in the shade region. For either forces or velocity distributions, the abnormal changes behave contrarily for cases with the rotating speed larger or smaller than the idle. Moreover, the more the rotating speed of the fore differs from the idle, the larger the abnormal values become.     

超声波辅助提取欧李仁中苦杏仁苷的工艺优化

以欧李种仁为原料,采用超声辅助乙醇提取欧李种仁中苦杏仁苷,使用高效液相色谱仪进行检测,以苦杏仁苷得率作为检测指标,以乙醇浓度、液料比、提取温度、超声时间和超声功率为考察因素进行单因素试验,在此基础上结合二水平试验和响应面法对超声提取工艺进行优化,最终确定提取欧李种仁中苦杏仁苷的最佳工艺条件为液料比13:1(mL/g),乙醇浓度79%,提取温度70℃,超声时间40min,超声功率192W,该条件下苦杏仁苷得率可达6.01%。