为了探究含金属颗粒悬浮燃料的点火和燃烧特性,制备了含5%纳米铝颗粒(Al NPs)的HD-01和四环庚烷(QC)的高密度悬浮燃料,采用雾化激波管测试了两种悬浮燃料在不同压力和温度下的点火延时P,通过拟合计算得到了表观点火活化能,分析了悬浮燃...为了探究含金属颗粒悬浮燃料的点火和燃烧特性,制备了含5%纳米铝颗粒(Al NPs)的HD-01和四环庚烷(QC)的高密度悬浮燃料,采用雾化激波管测试了两种悬浮燃料在不同压力和温度下的点火延时P,通过拟合计算得到了表观点火活化能,分析了悬浮燃料的点火燃烧机理,采用高速摄像机记录了点火燃烧的流场图像。结果表明,悬浮燃料静置4周后无颗粒聚沉现象;在0.05 MPa和0.1 MPa下、1450 K和1750 K内,Al NPs可使HD-01和QC燃料的点火延时缩短约50%,表观点火活化能由161.4 k J·mol^(^(-1))和120.3 k J·mol^(-1)分别降低至156.5 k J·mol^(-1)和112.8 k J·mol^(-1);推测燃烧机理为铝原子优先与O2反应生成O自由基,进而加速燃烧反应。此外,Al NPs能够完全燃烧并促进燃料燃烧过程中的能量释放。展开更多
In our previous work, a low-shear stirred bioreactor was explored. With a pitched blade turbine impeller downflow(PBTD) used, the shear stress generated is high compared with that in some low shear axial flow impeller...In our previous work, a low-shear stirred bioreactor was explored. With a pitched blade turbine impeller downflow(PBTD) used, the shear stress generated is high compared with that in some low shear axial flow impellers. KHX impeller is an efficient axial flow impeller, which provides large onflow diffusivity and low shear force. In this work, the KHX impeller was applied in a lower-shear bioreactor and the performance of this reactor was evaluated and compared with that of the PBTD impeller. The experimental results show that the KHX impeller can disperse gas at lower power consumption and gives greater gas–liquid volumetric mass transfer coefficients than PBTD at the same power consumption. An empirical correlation for evaluating the mass transfer coefficient of the KHX impeller in the bioreactor is presented to provide reference for its industrial application.展开更多
文摘为了探究含金属颗粒悬浮燃料的点火和燃烧特性,制备了含5%纳米铝颗粒(Al NPs)的HD-01和四环庚烷(QC)的高密度悬浮燃料,采用雾化激波管测试了两种悬浮燃料在不同压力和温度下的点火延时P,通过拟合计算得到了表观点火活化能,分析了悬浮燃料的点火燃烧机理,采用高速摄像机记录了点火燃烧的流场图像。结果表明,悬浮燃料静置4周后无颗粒聚沉现象;在0.05 MPa和0.1 MPa下、1450 K和1750 K内,Al NPs可使HD-01和QC燃料的点火延时缩短约50%,表观点火活化能由161.4 k J·mol^(^(-1))和120.3 k J·mol^(-1)分别降低至156.5 k J·mol^(-1)和112.8 k J·mol^(-1);推测燃烧机理为铝原子优先与O2反应生成O自由基,进而加速燃烧反应。此外,Al NPs能够完全燃烧并促进燃料燃烧过程中的能量释放。
基金Supported by the National Basic Research Program of China(2010CB630904)the National Natural Science Foundation of China(21276004,20990224)+1 种基金the National Natural Science Fund for Distinguished Young Scholars(21025627)the National High Technology Research and Development Program of China(2012AA061503)
文摘In our previous work, a low-shear stirred bioreactor was explored. With a pitched blade turbine impeller downflow(PBTD) used, the shear stress generated is high compared with that in some low shear axial flow impellers. KHX impeller is an efficient axial flow impeller, which provides large onflow diffusivity and low shear force. In this work, the KHX impeller was applied in a lower-shear bioreactor and the performance of this reactor was evaluated and compared with that of the PBTD impeller. The experimental results show that the KHX impeller can disperse gas at lower power consumption and gives greater gas–liquid volumetric mass transfer coefficients than PBTD at the same power consumption. An empirical correlation for evaluating the mass transfer coefficient of the KHX impeller in the bioreactor is presented to provide reference for its industrial application.
