Zero-Net-Mass-Flux Jet Assisted Dry Powder Inhaler Mouthpiece Exit Flow Dynamics

Abstract: Dry powder inhalers (DPI) are commonly used for the treatment of respiratory diseases such as asthma and chronic obstructive pulmonary diseases. The available DPIs in the market have two main drawbacks: (i) they are typically passive systems which require fast and strong inhalation of the drug from the inhaler, which may be challenging for some patients such as children, the elderly, or patients with a compromised respiratory system, (ii) due to the sub-optimal aerodynamics of the current DPI designs, most of the drug particles are deposited in the patient's throat region instead of reaching the lungs as intended. Thus, a large portion of the loaded drug gets wasted and patients often receive a sub-optimal dose. This project aims to investigate the flow physics of a new type of assisted DPI using a zero-net-mass-flux jet (ZNMFJ) device to overcome these limitations by providing additional axial momentum in the jet flow exiting from the DPI mouthpiece. In the current experimental set-up, a loudspeaker is used to generate the ZNMFJ. The DPI mouthpiece is a hollow tube with radial inlets at one end where the ZNMFJ device is located and the mouthpiece exit at the other end. To investigate the aerodynamic flow of this ZNMFJ assisted DPI, particle image velocimetry (PIV) is employed to experimentally measure the two-component - two-dimensional (2C-2D) instantaneous velocity field emerging from the DPI mouthpiece. Insights provided through this work will be used to assist in the development of this non-passive drug deposition DPI that may provide more effective treatments specially for infants, elderly, and chronic asthma patients. Keywords: dry powder inhaler, zero-net-mass-flux jet, particle image velocimetry, inlets, jet-exit velocity, axial momentum