Flow Characteristics of New Disposable Inhaler Spacer at Different Geometry

Abstract

During the pandemic COVID-19, the data statistic stated there were patients with respiratory problem got infected. Due to the respiratory problem, the metered-dose inhaler and spacer were used as one of the treatment methods. The research objective is to identify the flow characteristics in the new disposable inhaler spacer and modify the geometry of the disposable inhaler spacer to obtain the desired velocity. The circular shape of the model disposable inhaler spacer is selected among the previous researchers. The materials of new disposable inhaler spacer such as paper and polylactic acid (PLA) do not affect the flow characteristics.  Several geometry models suppressed the fillet and chamfer to reduce the skewness below 0.94. The flow characteristics such as turbulence kinetic energy (TKE), turbulence eddy dissipation (TED), velocity, particle velocity magnitude, streamline and vector velocity are obtained from the ANSYS Workbench Fluent 19.2 with the actual scale (1:1). The setup input data based on the selected parameters such as viscosity model, the properties of drugs (salbutamol and propellant), discrete phase model (DPM) equal to 80, boundary condition model and the method SIMPLE are based on the previous researcher. The nozzle injection used the dimension 0.49 millimetre for the five geometry models. The simulation work is verified with the result of the previous simulation work. The transient flow used the 0.01 of time step size for 300 numbers of steps within an iteration. Key findings support that computational analysis can differentiate the complexity of the models. The trends of TED, TKE and velocity graph showed the approximate value between the model geometries. Overall, the study successfully achieved the desired velocity magnitude in term of visual and graph of the different geometry model. The future work can use as a benchmark to design a new geometry model.