为建立高固气比(10 kg/kg< Z < 135k 岁 kg )的气体一粉煤混合物流经文丘里管收缩段的压降模型,首先分析了密相气力输送系统中文丘里管收缩段内的压降组成,包括气相造成的压降与固相造成的压降,气相加速压降与固相加速压降,然后通过数值计算方法实现模型,得到收缩段沿程压降、气体速度和颗粒速度等的变化特性。结果表明:在一定的工艺操作参数下,模型预测不同收缩角(5°,9°和13°)对应的收缩段压降值与实验值吻合较好,总体偏差在士 20 %以内;气体损失的静压能绝大部分用于高固气比气体一粉煤混合物中的固体颗粒的加速上,导致收缩段内固体颗粒加速压降占收缩段总压降的 87 %-97 %。
In order to establish a pressure drop model of gas-coal mixture flowing through the contraction section of Venturi with high solid-gas ratio (10 kg/kg 〈 Z 〈 135 kg/kg), the pressure drop composition in the contraction section of Venturi in the dense phase pneumatic conveying system was analyzed, including pressure drop generated by gas and solid, and acceleration pressure drop of gas and solid. Then the model was realized by the numerical calculation method, and the variation characteristics along the distance of the pressure drop, gas and solid velocity were obtained. The results show that predicted results of pressure drop in Venturi contraction section at different contraction angle (5°, 9° and 13°are in good agreement with the experimental results giving total deviation within +20% under certain operating parameters, and the loss of static pressure energy of gas is mostly used for the acceleration of solid in gas-coal mixture with high solid-gas ratio, which leads to the acceleration pressure drop of the solid in the contraction section of the total pressure drop of 87% -97%.