## 1 Introduction
They cannot be avoided entirely, as they are often necessary for determining basic contact parameters and calibrating the numerical model [19]. More suitable and increasingly used are discrete numerical methods, which enable the description and even optimization of highly complex geometries and conveyors. Although their mechanical design appears simple, the behaviour of granular solids and powders during transport is highly complex [16]. Screw conveyors have previously been examined and analyzed in the existing literature, with DEM analysis presented in reference [20]. This analysis specifically investigated screw and shaftless screw conveyors for various free-flowing bulk solids, which are typically easy to handle. As demonstrated in reference [21], multiple existing studies have already addressed the impact of geometric design, operating parameters, and mixing characteristics on various types of screw conveyors and feeders. [PERSON] et al. [22] investigated how varying inclination angles, rotational speeds, and filling rates impact conveyor performance including conveying velocity, mass flow rate and power consumption. [PERSON] et al. [23] utilize the Discrete Element Method (DEM) to assess the efficiency of a screw conveyor. The analysis involves visualizing particle motion, determining angular and axial particle velocities, calculating overall torque and total force, and evaluating kinetic energy and total energy dissipation within the system. [PERSON] et al. [24] simulated particle flow in a screw conveyor, observing increased mass flow rates with higher speeds and filling levels. [PERSON] et al. [25] studied screw feeders with different blade designs. It reveals critical factors impacting flow uniformity, power consumption, and wear, emphasizing the importance of screw design in optimizing feeder performance. Provided studies are limited. They examined the screw conveying characteristics, omitted significant material properties, including particle shape and size, and neglected to properly calibrate material properties. [PERSON] et al. [26] take a step further when they address the impact of particle shape, particularly faceted polyhedral particles, on the behaviour of materials in screw conveyors. It finds that while spheres hold similar bulk discharge rates to certain polyhedra at lower speeds, polyhedra generally exhibit a larger fraction of normal impacts between particles and increased abrasion, while spheres dissipate more energy as shear between particles. [PERSON] et al. [27] also studied significance of particle shape on conveying performance and wear, with particles' shape index affecting collision frequency and energy consumption, particularly in particle-wall collisions. In summary, existing research on screw conveyors has provided insights into conveyor performance under varying operational conditions such as rotational velocities, filling rates, and screw designs, influencing mass flow rates. However, these studies often overlook particle properties like shape, size and calibration overall, limiting the accuracy of conveyor descriptions and study applicability across different operating regimes and states of conveying materials. Additionally, despite a partial understanding of how input parameters impact specific conveyor configurations, there remains a notable absence of studies where optimization is conducted to determine optimum parameters. This was also recently highlighted by [PERSON] et al. [14], who first proposed a method based on the combination of DEM and NSGA-II algorithms to analyze and improve the conveying efficiency while reducing blade wear in vertical screw conveyors transporting cohesive particles. Moreover, there are multiple research papers focusing on the combined analysis of observing different outputs of the system. For example, conveying efficiency and blade wear or conveying efficiency and power consumption, highlighting a significant gap in the literature. Moreover, there's an additional gap in addressing structural integrity concerns during conveyor design.