Steel surface preparation processes in the shipbuilding industry based on abrasive blasting generate high dust concentrations, including the hazardous respirable fraction. The present study focuses on the computational fluid dynamics (CFD) assisted design assessment of a modular water-curtain head integrated with the cleaning module of a mobile magnetic robot used in abrasive blasting. The proposed solution is intended to reduce pollutant emissions at source while maintaining the low mass, compact geometry and serviceability required for robotic operation on ferromagnetic surfaces. Comparative numerical analyses were carried out using ANSYS CFX for two design variants of the supply manifold, differing in the position of the inlet relative to the nozzle channels. The study focused on flow stability, pressure distribution and the uniformity of mass flow rate across six full-cone spray nozzles. The results showed that the inlet location affected the hydraulic balance of the manifold and the uniformity of nozzle supply. The configuration with the inlet located between the nozzle channels provided a more uniform distribution of the working medium, whereas the configuration with the inlet adjacent to one nozzle channel generated stronger local asymmetry in the inlet region. The results indicate that comparative CFD analysis can effectively support the design of compact spraying heads for robotic abrasive blasting systems.