# CFD and Experimental Comparison for Micro-Pump Performance in Space Applications: A Case Study
## 1 Introduction
This method, which involved designing and comparing five impellers with varied blade profiles using computational fluid dynamics (CFD), resulted in impellers that exhibited superior hydraulic performance, including higher efficiency and lower torque under design conditions. Shape optimization of a low-specific-speed centrifugal pump was also conducted using genetic algorithms and Bezier curves [25]. Additive manufacturing (AM) technology has emerged as a promising tool, particularly for space applications, offering advantages such as design flexibility, performance improvements, and reductions in production time and costs. [PERSON] at al. [26] study reviewed various materials used in AM processes, such as metals, polymers, and composites, and explored their impact on reducing waste and improving energy efficiency. It emphasized the role of AM in achieving sustainable operations across different industries, providing insights into emerging materials and methods that can enhance environmental benefits. [PERSON] et al. [27] presented a comprehensive review of 3D printing (additive manufacturing), covering the range of materials, methods, applications, and the challenges faced by the industry. It also addressed challenges related to material properties, process control, and cost, offering a detailed perspective on the future of 3D printing technologies. [PERSON] [28] explored the materials, applications, and development trends in additive manufacturing technology. The paper focused on advancements in materials used in AM, including the growing importance of multi-material and hybrid printing. Preliminary studies on hydraulic components, such as closed impellers made from Inconel 625, have validated the geometrical accuracy of AM parts, demonstrating optimal printing orientations and minimal process defects. [PERSON] et al. [29] explored the use of additive manufacturing (AM) for developing a closed pump impeller intended for mechanically pumped fluid loop systems. The study used AM techniques to design and produce an impeller, assessing the advantages of AM over traditional manufacturing methods, such as reduced material waste and the ability to create complex geometries. The results demonstrated the feasibility of using AM to produce high-performance pump components with improved efficiency and reduced lead time. [PERSON] et al. [30] further investigated the manufacturing of a closed impeller using Selective Laser Melting (SLM) technology for fluid loop systems. The study focused on the specific AM technique, examining the quality, precision, and material properties of the impeller produced. The results showed that SLM AM enabled the creation of complex geometries, leading to improvements in performance, reduced material usage, and greater design flexibility for pump components in fluid loop systems. Comparisons between classical machined impellers and those produced using AM techniques showed minimal differences in pressure rise and mass flow rate, with AM titanium impellers exhibiting less than 1% variation [31]. These findings suggest that AM technologies hold great potential for producing high-performance centrifugal pumps for space applications, reducing limitations associated with conventional manufacturing methods. While numerous studies have improved centrifugal pump performance through geometric optimization, turbulence modeling, and advanced manufacturing techniques, challenges remain in accurately predicting pump performance at small scales, where the interplay between Reynolds and Taylor numbers complicates flow behavior and loss estimation. These issues are particularly acute when validating CFD simulations against experimental data, as discrepancies can be significant across different operating regimes. This paper is framed as a case study comparing CFD predictions with experimental measurements for small-scale centrifugal pumps.