Multi-objective optimisation of auxiliary-air cyclone conveying using CPFD and RSM

• This paper uses CPFD to numerically simulate the auxiliary intake pipe. • This paper uses the response surface method to optimise the structural parameters. • Auxiliary intake velocity has the greatest impact on the target value. • The target value is most affected by the angle and spacing of the auxiliary intake. • Cyclone pneumatic conveying reduces energy consumption. In recent years, pneumatic conveying systems are widely used in various industries such as mining, mineral processing, and power generation, and the pneumatic conveying market is expected to reach USD 30 billion by 2025. In order to reduce the prominent problems such as coal breakage, pipe wall wear, and high system energy consumption during pneumatic conveying, vortex flow has become one of the popular technologies to reduce the pressure drop in conveying pipelines and improve pneumatic conveying systems. In this paper, an intermittent cyclonic assisted air intake system is proposed and numerically simulated based on the computational particle fluid dynamics (CPFD) method for a horizontal pipe with added assisted air intake. The structural parameters of the auxiliary air intake (auxiliary air intake angle, auxiliary air intake velocity, and spacing between two adjacent auxiliary air intakes) are explored in a one-factor test and optimized based on the response surface method in a multi-objective approach. The results show that when the main intake velocity is 13 m/s, adding an auxiliary intake with an intake velocity of 8 m/s, an intake angle of 45°, and an adjacent auxiliary intake spacing of 1250 mm can effectively reduce the horizontal pipeline pressure drop. Comparison of this condition with the main intake speed of 13 m/s, 15 m/s, and 17 m/s without the addition of auxiliary air intake revealed that the power consumption coefficient was reduced by 10.59 %, 35.36 %, and 34.81 %, respectively.