This 2024 assignment for Howorth Air Technology Ltd focused on "Modelling and Optmisation of Ultra-clean ventilation" within the healthcare sector. Using computational fluid dynamics (CFD), the team translated the existing project brief into a structured technical assessment. The work was intended to show why the system behaved as it did, how performance changed across credible scenarios, and which interventions offered the strongest engineering value.

This project focused on simulating and assessing the performance of Howorth’s ExFlow 28 Evolution Ultra-Clean Ventilation (UCV) system within a representative operating theatre. Using advanced Computational Fluid Dynamics (CFD) techniques, a detailed three-dimensional digital model was created to capture airflow patterns, velocity fields, and air exchange pathways between the theatre and its surrounding spaces. The model incorporated critical features such as pressure stabilisers, transfer grilles, exhausts, and door gaps, ensuring realistic boundary conditions and highly accurate results. A high-resolution mesh enabled precise prediction of complex flow behaviour, while validation against experimental measurements confirmed the robustness of the simulations. The study not only demonstrated compliance with stringent air quality and velocity criteria but also provided clear visualisations—using contours, vectors, and streamlines—to support stakeholder decision-making. This work highlights our capability to deliver advanced CFD models for system optimisation, performance validation, and future product development

The methodology centred on a detailed three-dimensional CFD model of the ventilation system, plenum and occupied clinical environment. The representation retained supply diffusers or HEPA panels, extraction grilles, pressure stabilisers, transfer paths, doors, furniture, equipment, occupants and the critical clean zone. Boundary and operating conditions covered normal and disturbed operating conditions, representative heat loads, pressure cascades, door gaps or openings, occupancy and relevant supply and extract set-points, with material, fluid and equipment properties assigned from the available design information. Resolution was concentrated in regions where steep velocity, thermal, concentration or phase gradients were expected, while the overall model remained efficient enough to compare several credible configurations. This balance allowed system-level performance to be linked to the local mechanisms responsible for it.

The assessment compared plenum, diffuser, canopy and extract configurations together with practical control or balancing changes. Performance was judged using supply uniformity, downward-flow quality, velocity across the critical zone, recirculation, stagnation, particle-removal performance, pressure relationships and draught risk. Results were reviewed through quantitative summaries and engineering visualisations, such as contours, vectors, streamlines, sections and time histories, selected to suit the physics. Important assumptions and operating uncertainties were considered so that the recommendations relied on repeatable comparative trends rather than a single nominal case.

For Howorth Air Technology Ltd, the principal value was evidence that supported clean-zone performance, product optimisation and standards-aware clinical ventilation design. The final evidence linked each recommendation to the relevant model or process output, making it suitable for internal design reviews, supplier or contractor discussions and, where applicable, planning, safety or regulatory dialogue. The work also created a reusable baseline that can be updated as geometry, operating data or test results become available, reducing the cost and risk of later design iterations.