Investigating rules of design to optimise pMDI plume properties
Sebastian White1, Franck Rubiconi1, John Sendall1, Jeremy Baker1, Alim Thawer1, Fred Hamlin1 & Baudouin Géraud1
1Cambridge Consultants Ltd, 29 Science Park, Milton Road, Cambridge, CB4 0DW, UK
Summary
An experimental investigation into the relative impact of a pMDI’s orifice diameter and sump volume on the resultant plume was conducted as an empirical approach to optimise nozzle design. Image processing of high-speed videos and light scattering based particle size acquisition were implemented to quantify the relative impact of each geometric parameter. Five metrics were used to quantify performance: Delay, Optical Duration, plume Expansion Coefficient, Dv50 and plume Cone Angle. Quantitative comparison of correlation coefficients between measurements show that orifice diameter has a significantly greater impact on performance than the sump Volume.
Key Message
The experimental investigation reported here compares quantitatively the impact of nozzle parameters on the plume properties. This method could be extended to other parameters to optimise the design of pMDIs actuators.