Choking Phenomena of Gas‐Powder Flows at Sonic Velocity
Choking Phenomena of Gas‐Powder Flows at Sonic Velocity
复制标题
DOI：
10.1002/srin.200506081
复制
发表时间：
2005-10
影响因子：
2.2
通讯作者：
Qiang Li;Z. Zou;S. Tan
中科院分区：
文献类型：
--
作者：
Qiang Li;Z. Zou;S. Tan
采用三种不同物理性质（密度、比热容和导热系数）的Al 2 O3、空心Al 2 O3（H-氧化铝）和Al粉末，对水平等截面管道内气粉两相流的阻塞现象进行了实验研究。分析了质量流量与入口滞止压力之间的关系，定义了气粉两相流的表观声速。通过对不同粉末的实验结果的比较，得出了粉末的物理性质对ASV的影响。定义了两个表征阻塞现象的特征参数：固相有效比热容（ESHC）和混合物有效等熵指数（EIE）。ESHC不仅可以通过实验测量，也可以通过数值方法计算。计算结果与实测结果吻合较好。为了实现高炉喷煤的均匀化，建立了一个具有两个分支管道的模型喷煤系统，并进行了实验，以验证喷煤系统的阻流效果。试验结果表明，在阻塞过程中，无论下游条件如何不同，分支管道中的PC流量都能很好地均衡。
Choking phenomena of gas‐powder flows in a horizontal constant cross‐section duct are experimentally studied using three kinds of powders: Al2O3, hollow Al2O3 (H‐alumina) and Al, with different physical properties such as densities, specific heat capacities and thermal conductivities. The relationship between the mass flowrate and inlet stagnant pressures is analysed and the apparent sonic velocity (ASV) of gas‐powder flows is defined. The influences of physical properties of powders on the ASV are obtained by the comparison between the experimental results of different powders. Two characteristic parameters, the effective specific heat capacity (ESHC) of solid phase and the effective isentropic exponent (EIE) of the mixture, are defined to describe the choking phenomena. The ESHC is not only measured through experiment but also calculated by numerical method. The calculated results are well consistent with the measured ones. As a preliminary application test for choking phenomena ‐ in order to uniform the pulverized coal injection (PCI) into a blast furnace ‐, a model PCI system with two branch pipes was set up and tests were carried out to verify the choking effect. The test results show that, during choking, the PC flow rates in the branch pipes can be well equalized no matter how much the downstream conditions differ from each other.