Doctorat / Thèse — Experimental investigation and modelling of foam-flow cleaning in milking systems – FOAMAT

Doctorat / Thèse Type de financement : Contrat Doctoral. Date limite de candidature : 20/12/26. Discipline : Chimie.

Cleaning milking systems is essential for maintaining equipment hygiene and milk quality. Conventional cleaning-in-place (CIP) procedures require water, energy and detergents. In complex circuits, bends, junctions, vertical sections and changes in diameter can lead to uneven liquid renewal and mechanical action, allowing dairy residues and biofilms to persist. Cleaning by foam flow offers an alternative approach, with the potential to improve contact with equipment surfaces while reducing resource consumption. Its effectiveness depends on foam formulation, liquid fraction, bubble size, drainage, stability and flow conditions. A key scientific challenge is to connect these properties to near-wall hydrodynamics, mechanical stresses and contaminant removal, and to determine how laboratory findings can be transferred to representative milking circuits. Within the FOAMAT project, this PhD will combine foam physical chemistry, millifluidic experiments and computational fluid dynamics (CFD). The objective is to establish relationships between foam properties, flow behaviour and cleaning performance, and to support the development of operating conditions suitable for pilot-scale applications. The doctoral researcher will undertake the following activities: • Foam formulation and characterisation: contribute to the selection of surfactant formulations and measure foamability, bubble-size distribution, liquid fraction, drainage and stability. Characterise foam rheology and interactions with materials representative of dairy equipment. • Experimental investigation and instrumentation: contribute to the design and instrumentation of a foam generation and circulation system. Investigate straight sections, bends, junctions and diameter changes under controlled conditions. Analyse flow-rate and pressure measurements, imaging data and, where appropriate, local shear and conductivity measurements. • Numerical modelling: develop CFD models, particularly using COMSOL Multiphysics, incorporating an effective description of foam rheology. Compare simulations with experimental observations to identify critical flow regions and conditions favourable to cleaning. • Cleaning assessment and pilot-scale validation: investigate the removal of dairy residues and microbial contamination. Contribute to the analysis of pilot trials conducted with ACTALIA and on the Institut de l’Élevage’s PiloTraite platform. Assess rinsing requirements and compare water, energy and chemical consumption with conventional CIP over the complete cleaning cycle. • Scientific dissemination: analyse and interpret results, prepare scientific publications, present findings at conferences and contribute to technical recommendations for the dairy sector. FOAMAT is coordinated by Université de Caen Normandie, in partnership with ACTALIA and Institut de l’Élevage (Idele). Kersia provides industrial support relating to detergent formulations and their use, while CNIEL contributes through advisory exchanges.

Référence Campus France : CF202649666.