Study On Energy Consumption Of Pneumatic Conveying Polyacrylamide Particles By CFD-DEM

A thorough study about the energy consumption in the pneumatic conveying system of the polyacrylamide which is a kind of important chemical engineering materials is conducted by the combination of theoretical analysis,experimental research and numerical simulation.The constructed CFD-DEM model is exploited to simulate horizontal pneumatic conveying.Firstly,the accuracy of the model is verified by comparing with the experimental data.Furthermore,the effects of particle shape,particle size,and inlet pressure on the energy consumption of the horizontal pipe are also studied.The results show that in the dilute phase horizontal pneumatic conveying,the particle shape has minimal impacts on pressure drop;the pressure drop is positively correlated with particle size before stabilization and negatively correlated after stabilization.The pressure drop decreases initially,then gradually increases,during the growth of fluid pressure.Consequently the optimal pressure for each particle flow is determined.The constructed CFD-DEM model is also exploited to simulate the pneumatic conveying system.Firstly,the applicability of the model in pneumatic conveying system was verified.Moreover,the effects of gas mass flow rate,particle mass flow rate and mass loading ratio on the energy consumption of horizontal pipes,vertical pipes and elbow pipes were deeply studied.The results show that with the increase of gas flow,the pressure drop in the dilute phase horizontal pneumatic pipe increases,in the dense phase horizontal pipe decreases;and the pressure drop in the dilute phase vertical pipe decreases first and then increases,in the dense phase vertical pipe gradually increases;the pressure drop of bends is more complex and has certain regularity.The pressure loss in the accelerating section decreases with the increase of the particle flow,and thenon-accelerating sectionIt is defined that mass loading ratio of that change dilute phase pneumatic conveying to non plug dense phase pneumatic conveying is 20.44.According to the theroy of Barth additional pressure drop,combined with the dimensionless analysis,the additional pressure drop coefficient can be derived.And then Froude number of the pneumatic conveying system is further studied.The results present that Froude number can reflect the flow field in the pipe.The quantitative relationship between Froude number,mass loading ratio and particle mass flow for each horizontal pipe,vertical pipe and bend pipe is obtained.Furthermore,according to the simulated calculation of the pressure loss in each pipe,the predictive pressure drop model of pneumatic conveying pipe is established,and the accuracy of this model is verified by comparing with the experimental data.